[Federal Register Volume 60, Number 183 (Thursday, September 21, 1995)]
[Rules and Regulations]
[Pages 49048-49083]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-22771]




[[Page 49047]]

_______________________________________________________________________

Part II





Department of Transportation





_______________________________________________________________________



Research and Special Programs Administration



_______________________________________________________________________



49 CFR Part 171, et al.



Crashworthiness Protection Requirements for Tank Cars; Detection and 
Repair of Cracks, Pits, Corrosion, Lining Flaws, Thermal Protection 
Flaws and Other Defects of Tank Car Tanks; Final Rule

  Federal Register / Vol. 60, No. 183 / Thursday, September 21, 1995 / 
Rules and Regulations   

[[Page 49048]]


DEPARTMENT OF TRANSPORTATION

Research and Special Programs Administration

49 CFR Parts 171, 172, 173, 179, and 180

[Docket Nos. HM-175A and HM-201; Amdt Nos. 171-137, 172-144, 173-245, 
179-50, and 180-8]
RIN 2137-AB89 and 2137-AB40


Crashworthiness Protection Requirements for Tank Cars; Detection 
and Repair of Cracks, Pits, Corrosion, Lining Flaws, Thermal Protection 
Flaws and Other Defects of Tank Car Tanks

AGENCY: Research and Special Programs Administration (RSPA), DOT.

ACTION: Final rule.

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SUMMARY: RSPA is amending the Hazardous Materials Regulations (HMR) to: 
Require facilities that build, repair, and ensure the structural 
integrity of tank cars, to develop and implement a quality assurance 
program (QAP); allow the use of non-destructive testing (NDT) 
techniques, in lieu of currently prescribed periodic hydrostatic 
pressure tests, for fusion welded tank cars; require thickness 
measurements of tank cars; allow the continued use of tank cars, with 
limited reduced shell thicknesses, for certain hazardous materials; 
increase the frequency for inspection and testing of tank cars for 
added safety; clarify tank car pretrip inspection requirements; expand 
the use of thermal protection systems and head protection on tank cars 
to include certain other high hazard materials; add new requirements 
for bottom-discontinuity protection; require the use of protective 
coatings on insulated tank cars; prohibit the use of self-energized 
manways located below the liquid level of the tank; remove 
``grandfather'' provisions allowing certain uses of tank cars; and 
improve the puncture resistance of tank cars used for certain high 
hazard materials, including those that are poisonous-by-inhalation 
(PIH) and those determined by the Environmental Protection Agency (EPA) 
to pose health and environmental risks.
    These actions are being taken to enhance the safe transportation of 
hazardous materials in tank cars. The intended effects of these actions 
are to improve the crashworthiness of tank cars and to increase the 
probability of detecting critical tank car defects.

DATES: Effective date. The effective date of these amendments is July 
1, 1996.
    Compliance date. Voluntary compliance with the regulations, as 
amended herein, is authorized November 1, 1995.
    Incorporation by reference date. The incorporation by reference of 
certain publications listed in these amendments is approved by the 
Director of the Federal Register as of July 1, 1996.

FOR FURTHER INFORMATION CONTACT: Ed Pritchard (telephone 202-366-0509) 
and James H. Rader (telephone 202-366-0510), Hazardous Materials 
Division; or Thomas A. Phemister (telephone 202-366-0635), Office of 
Chief Counsel, Federal Railroad Administration, 400 Seventh Street, 
S.W., Washington, D.C. 20590-0001.

SUPPLEMENTARY INFORMATION:

I. Introduction

    This final rule consolidates two related notices of proposed 
rulemaking published under Docket HM-175A [58 FR 52574, October 8, 
1993] and Docket No. HM-201 [58 FR 48485 September 16, 1993], that 
address the safe performance of tank cars used to transport hazardous 
materials. RSPA believes that, by consolidating these two rulemakings, 
changes to sections that are affected by both rules will be more easily 
understood by readers. This preamble discusses separately, for each 
rulemaking, the notices of rulemaking and comments received in response 
to these notices. A consolidated ``Review by Section Summary'' 
summarizes the changes made under this final rule.
    The Federal Railroad Administration (FRA) has enforcement authority 
for tank cars and rail transportation. FRA developed these rulemakings 
jointly with RSPA.

II. Docket HM-175A--Crashworthiness Protection Requirements for 
Tank Cars

A. Background

    Based on research and on the FRA's continuing review of serious 
accidents, involving the transportation of hazardous materials in tank 
cars in the United States and Canada, RSPA issued a number of 
regulations to improve the survivability of tank cars in 
accidents.1 In these rulemakings, RSPA required the installation 
of a tank-head puncture-resistance system (head protection), a coupler 
vertical restraint system (shelf couplers), insulation, and a thermal 
protection system for certain high-risk hazardous material ladings. The 
difference between a ``thermal protection system'' and ``insulation'' 
is that a ``thermal protection system'' protects a tank from a pool or 
torch-fire environment. In contrast, ``insulation'' protects the lading 
inside the tank from ambient, temperature differentials, much like home 
insulation. The record shows that these systems, working in 
combination, have greatly reduced the potential harm to human health 
and the environment when tank cars are involved in accidents.

    \1\The discussions in the following rulemakings provide greater 
detail about each of these safety system requirements: Interlocking 
Couplers and Restrictions of Capacity of Tank Cars, Docket HM-38, 35 
FR 14215 (September 9, 1970); Tank Car Tank Head Protection, Docket 
HM-109, 41 FR 21475 (May 26, 1976); Shippers; Specifications for 
Pressure Tank Cars, Docket HM-144, 42 FR 46306 (September 15, 1977); 
Shippers, Specifications for Tank Cars, Docket HM-174, 49 FR 3473, 
(January 27, 1984); Specifications for Railroad Tank Cars Used to 
Transport Hazardous Materials, Docket HM-175, 49 FR 3468 (January 
27, 1984); Transportation of Hazardous Materials, Miscellaneous 
Amendments, Docket HM-166W, 54 FR 38790 (September 20, 1989); and 
Performance-Oriented Packaging; Changes to Classification, Hazard 
Communication, Packaging and Handling Requirements Based on UN 
Standards and Agency Initiative, Docket HM-181, 55 FR 52402 
(December 21, 1990).
---------------------------------------------------------------------------

    On October 8, 1993, RSPA published a notice of proposed rulemaking 
(NPRM) under Docket HM-175A (58 FR 52574) based, in part, on 
recommendations issued by the National Transportation Safety Board 
(NTSB) and comments received in response to an advance notice of 
proposal rulemaking published on May 15, 1990 [55 FR 20242], and a 
supplemental advance notice of proposed rulemaking published on August 
29, 1990 [55 FR 35327]. The NPRM solicited comments on the costs and 
safety benefits that would be derived should the HMR be amended in the 
following areas: (1) Tank-head protection; (2) thermal protection; (3) 
self-energized manways below the tank liquid level; (4) non-pressure 
tank cars for PIH materials; (5) grandfather provisions allowing use of 
certain tank cars conforming to former standards; (6) bottom 
discontinuity protection on tank cars; (7) protective coatings on 
insulated tanks; and (8) tank cars of limited and designated 
specifications, with greater protection in accidents for transporting 
materials determined by EPA to pose health and environmental risks.
    On January 6, 1994, FRA and RSPA held a public hearing to solicit 
information to assist in deciding what actions, if any, should be taken 
to improve the survivability of tank cars involved in hazardous 
materials accidents. Twelve persons made presentations at the public 
hearing. In addition, RSPA received 37 written comments in response to 
the NPRM from representatives of trade associations and the various 
industries that own, lease, transport, or use tank 

[[Page 49049]]
cars. All written and oral comments were given full consideration.

B. Tank Cars Transporting ``Thermally Reactive Materials'' (Materials 
That May Violently Decompose or Polymerize When Exposed to Fire)

    In the NPRM, RSPA proposed to require the use of full-head 
protection and thermal protection on tank cars used for certain 
materials termed, ``thermally reactive.'' These materials, listed by 
name, are thought by many to be capable of a violent decomposition or 
polymerization reaction when exposed to fire. For these materials, the 
critical temperature for the tank car, and its thermally reactive 
lading, may be the heat at which the material undergoes decomposition 
or polymerization--as opposed to the temperature at which the steel of 
the tank becomes so plastic, it begins to lose tensile strength.
    The proposal was based on several accidents involving thermally 
reactive materials. For example, on August 2, 1988, at 9:00 p.m., in 
Brazoria, Texas, 13 cars of a Union Pacific freight train 
derailed.2 Seven of the derailed tank cars contained acetaldehyde, 
and none of these tank cars had a thermal protection system, which was 
not required. Two acetaldehyde tank cars sustained coupler punctures 
and released their contents, which ignited. The resulting fire engulfed 
four other acetaldehyde tank cars, and each of them had a total failure 
or rupture of the tank shell within 5 to 10 minutes after the 
derailment. Witnesses reported 3-4 explosions between 9:05 p.m. and 
9:10 p.m.

    \2\Union Pacific Derailment at Brazoria, Texas, FRA Accident 
Investigation No. 137-88, Railroad Report No. 0888H0200, August 2, 
1988.
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    In another accident, NTSB found that the puncture of a tank car 
containing hydrogen peroxide resulted in a release of lading and, when 
the hydrogen peroxide combined with contaminants on the ground, a 
chemical reaction occurred causing a fire.3 The fire heated and 
ignited nearby polyethylene pellets, causing an explosion of the 
hydrogen peroxide tank car and releasing a force equivalent to an 
explosion of 10 tons of TNT (trinitrotoluene).

    \3\Collision and Derailment of Montana Rail Link Freight Train 
with Locomotive Units and Hazardous Materials Release, Helena, 
Montana, February 2, 1989, National Transportation Safety Board 
Report NTSB/RAR-89/05, National Transportation Safety Board, 
Washington, D.C.
---------------------------------------------------------------------------

    Most commenters opposed the requirement for full-head protection or 
thermal protection on tank cars used for thermally reactive materials. 
In clarifying its comments on the NPRM, the Association of American 
Railroads (AAR) stated that full-head protection is not necessary for 
tank cars used for these materials, unless the materials pose another 
hazard that warrants such protection. Other commenters, such as 
American Petroleum Institute (API), Chemical Manufacturers Association 
(CMA), and the Compressed Gas Association, Inc. (CGA), suggested that 
RSPA open a new ANPRM to address these materials. A commenter stated--

the creation of this category has ramifications that reach far 
beyond this particular rulemaking, which deals with one mode of 
transportation (rail) and one type of packaging (tank cars). We are 
concerned with the likelihood that, in the future, the Department 
will expand the regulation of TRMs to affect other modes of 
transportation and types of packaging.

    Other commenters objected to the proposal to identify by list, 
rather than by definition, certain existing hazardous materials that 
would be designated ``thermally reactive.'' CMA challenged the 
placement of several chemicals on the list, such as ``styrene, monomer 
inhibited,'' ``vinyl toluene,'' ``vinylidene chloride,'' ``sulfur 
trioxide,'' and ``hydrogen peroxide.'' CMA further stated that--

[s]tyrene, for example, is flammable and can polymerize in an 
accident but solidifies causing little or no harm to the 
environment. For hydrogen peroxide tank cars, the proposed rule 
would create a safety hazard by requiring thermal protection.

    Another commenter stated that ``[s]ome of the materials on the list 
react violently when exposed to heat differentials and may decompose 
with explosive force * * * Other materials, however, decompose through 
polymerization into substances of relatively little hazard.'' The 
commenter further explained that the key to the polymerization of 
styrene is the absence of the inhibitor. Styrene is typically shipped 
with inhibitor concentrations great enough to cover fairly lengthy, 
unexpected delays in transportation. If a tank car of styrene is 
exposed to extreme external heat, disregarding its flammable nature, 
the inhibitor will dissipate rapidly as the temperature of the material 
rises above 125  deg.F., which will allow the polymerization process to 
begin. As a result of the polymerization, the internal heat of the 
product will increase, and, with increasing temperature, the process 
will accelerate.
    Several commenters opposed the requirement for a thermal protection 
system on tank cars used to transport ``hydrogen peroxide.'' One of the 
commenters stated that hydrogen peroxide does not polymerize or burn, 
and the products of decomposition--water and oxygen--are not toxic.
    Two commenters, Eka Nobel and FMC Corporation (FMC), furnished 
independent analyses of the fire effects on tank cars containing 
``hydrogen peroxide.'' Eka Nobel contracted with the IIT Research 
Institute (IITRI), which used FRA's computer model to analyze the fire 
effects on a tank car containing hydrogen peroxide.4 The results 
of IITRI's analysis indicate that a tank car constructed from stainless 
steel will meet the thermal protection criterion for withstanding the 
effects of a pool fire.

    \4\``Temperatures, Pressures and Liquid Levels of Tank Cars 
Engulfed in Fires,'' NTIS DOT/FRA/OR&D-84/08.11, (1984), Federal 
Railroad Administration, Washington, DC.
---------------------------------------------------------------------------

    FMC furnished a detailed, mathematical heat transfer model using a 
correlation contained in a National Fire Protection Association (NFPA) 
publication, ``NFPA Pamphlet No. 30.'' FMC stated that for materials 
that decompose exothermically, such as hydrogen peroxide, thermal 
stability requires that the heat losses to the surroundings balance the 
heat generated by the decomposition. Failure to remove the heat of 
reaction could lead to runaway decomposition, and if the increased 
pressure exceeds the burst pressure of the tank, the tank will fail. 
Furthermore, heat input causes oxygen generation from thermal 
decomposition of peroxide and vapor generation, by boiling off the 
water-peroxide mixture. FMC further stated that because water is more 
volatile than peroxide, the hydrogen peroxide concentration in the tank 
will increase (although this may be compensated by water formation and 
peroxide loss from thermal decomposition). If the peroxide 
concentration reaches 74 percent by weight, the vapors in equilibrium 
with the liquid (40 percent by weight of peroxide) can detonate, if 
ignited, causing the tank car to fail.
    The results of FMC's mathematical heat transfer model show that 
tank cars containing hydrogen peroxide (having no less than a 7-percent 
outage) will not fail and such tank cars will meet the thermal 
protection criterion in Sec. 179.18 of this final rule for withstanding 
the effects of a pool-fire. Readers who are interested in a detailed 
discussion of Eka Nobel or FMC's fire studies on tank cars containing 
hydrogen peroxide, should refer to the comments filed in the RSPA 
Dockets Unit.
    Many commenters suggested a performance-based definition as a means 
to ensure the proper identification and packaging of thermally reactive 
materials, because, with increasing temperature, all materials will 
reach a stability limit. 

[[Page 49050]]
These commenters suggested a performance-based definition that would 
include the polymerization potential; the rate of the chemical reaction 
(reaction kinetics); any highly exothermic reaction; the formation of 
gases, vapors, or fumes in a quantity sufficient to present a danger to 
human health and the environment; and any reactive by-products that 
could lead to over-pressurization of the tank. Commenters stated that a 
performance-based definition was the best way to ensure that the proper 
packaging requirements are attached to the appropriate hazardous 
materials.
    As evidenced from the comments, there is no single agreement on the 
best approach to identify these materials, nor to ensure the proper 
packaging requirements are assigned to these materials. Because of the 
multiplicity of these yet unresolved issues, the packaging requirements 
proposed in the NPRM for thermally reactive materials have not been 
adopted in this final rule.

C. Tank-Head Protection

    In the NPRM, RSPA proposed several changes relating to tank-head 
protection. The proposal would require tank-head protection on tank 
cars, used for all Class 2 materials and for tank cars constructed from 
aluminum or nickel plate, when used to transport a hazardous material. 
RSPA included Division 2.2 in its proposal to reduce the violent 
rupture hazard and the asphyxiation potential to railroad workers or 
bystanders exposed to the product if these tank cars are punctured. The 
proposal to require full-head protection for tank cars constructed from 
aluminum or nickel plate is based on the vulnerability of the tank head 
to a puncture. The top-half of the tank head is vulnerable to puncture 
in a derailment. Existing tank cars with half-head protection were 
excluded, based on RSPA and FRA's regulatory analysis discussed later 
in this preamble. Consistent with these proposed changes, RSPA also 
proposed to eliminate a grandfather provision, in place since 1984, 
following publication of a final rule under Docket HM-175, that permits 
certain tank cars, with a capacity of less than 70 kiloliters (kl; 
18,500 gallons), to continue in service without head protection.
    RSPA first introduced tank-head protection requirements after a 
series of railroad accidents in the late 1960s and early 1970s 
involving head punctures of tank cars (39 FR 27572 and 41 FR 21475). 
The requirements of, and criteria for, head protection were based on 
tests performed by FRA, the AAR, and the Railway Progress Institute 
(RPI) Tank Car Safety Research and Test Project in the early 1970s. In 
summary, these tests showed that head punctures, caused by over-speed 
impacts in railroad classification yards, generally occurred at speeds 
above 12 mph and often happened when a loaded tank car struck a 
standing empty tank car, causing the empty car to ``jump'' and ram its 
coupler into the head of the oncoming tank. A recent informal staff 
analysis of data on main-line accidents showed that objects, such as 
broken rails and couplers, may penetrate the top half of the tank head, 
indicating that head protection is essential, even though not 100 
percent effective, in a train derailment.
    The NPRM referenced the recent FRA research on puncture resistance, 
which shows that puncture resistance is strongly influenced by impact 
location, head and jacket thickness, and insulation thickness.5 
Stated differently, research demonstrates that puncture resistance is 
an inter-related function of head thickness, insulation thickness, and 
jacket thickness, and that the concept of ``head protection'' must 
include more than just traditional ``head shields.'' Based on the 
results of this research, FRA expects that certain tank cars may meet 
the 29 kilometers per hour (18-mph) threshold for puncture-resistance, 
prescribed in Sec. 179.16 of this final rule, without further 
modification.

    \5\Coltman, M., & Hazel, M., Jr., Chlorine Tank Car Puncture 
Resistance Evaluation (1992), Federal Railroad Administration, 
Washington, DC (NTIS DOT/FRA/ORD-92/11).
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    Tank cars currently equipped with half-head protection. Most 
commenters agreed that there is no need to require full-head protection 
on existing tank cars having only half-head protection.
    In comments filed in this docket, NTSB stated that the NPRM 
addressed many of their concerns, but noted the proposal failed to 
require existing tank cars used to transport Division 2.1 (flammable 
gas) materials, or other materials with extreme hazards, to be modified 
with full-head protection. Thus, these materials could be transported 
indefinitely in tank cars without full-head protection modifications.
    While we appreciate the concerns of NTSB, we are not able to 
establish a positive benefit/cost ratio by requiring modification of 
the existing tank car fleet, primarily because the half-head protection 
on existing cars is already about 95-percent effective. It is not 
credible to argue that greater safety gains are realized by mandating 
safety improvements on tank cars that currently have a 95-percent 
effective protection system, than by requiring improvements on tank 
cars without a head-protection system. The regulatory evaluation 
considered both approaches, with emphasis being placed on choosing the 
alternative offering maximum potential benefit to society, while 
imposing the least net cost. Based on the regulatory evaluation, this 
final rule does not require that existing half-head protection be 
removed and replaced with full-head protection.
    Head protection systems for existing tank cars with capacities less 
than 70 kl (18,500 gallons). RSPA received diverse comments in response 
to this proposal in the NPRM. One commenter agreed that class DOT 105 
tank cars having capacities less than 70 kl (18,500 gallons) and 
transporting Division 2.1, 2.2, and 2.3 materials, should have full-
head protection, unless already equipped with half-head protection.
    CMA supported the proposal to require full-head protection on newly 
built class DOT 105A tank cars, regardless of tank capacity, when used 
to transport a Division 2.1 or 2.3 material. The Reebie Associates 
report, submitted as part of CMA's comments, assumed that all tank cars 
would require head protection, except those that have a tank test 
pressure of 41.4 Bar (600 pounds per square inch [psi]).
    The Chlorine Institute agreed that head protection systems are now 
warranted for the transportation of chlorine, but recognized, based on 
FRA research and the accident history, that many tank cars currently 
used to transport chlorine meet the performance standard by virtue of a 
thick tank-head and a tank jacket.
    NTSB commented that RSPA should require tank-head protection, 
within 5 years, for all class 105 tank cars having capacities of less 
than 70 kl (18,500 gallons) when used to transport a Division 2.1 
(flammable gas) material as proposed in Option B of the NPRM.
    RPI commented that, except for the nominal 41 kl (11,000-gallon) 
capacity tank cars, existing tank cars of less than 70 kl (18,500-
gallon) capacity, transporting Division 2.1 materials or anhydrous 
ammonia, should have head-protection, but only half-head protection. 
RPI further commented that RSPA should exclude tank cars having a 
nominal capacity of 41 kl (11,000 gallons) from any head protection 
modification program, because most tank cars in this category are near 
or exceed 30 years of age; consequently, the economic life of the tank 
is nearing an end.
    RSPA and FRA believe that there is no longer a justification for 
excluding tank cars having a capacity less than 70 

[[Page 49051]]
kl (18,500 gallons) from the modification requirements. While CMA's 
report is not so optimistic on the use of DOT 105A500W specification 
tank cars, RSPA and FRA believe that most of these tank cars will meet 
the performance standard by virtue of their increased head thickness, 
insulation, and metal jacket. Because of the small number of tank cars 
in this category, and the small incremental cost to make such head 
protection modifications for those tank cars that do not otherwise meet 
the performance standard mandated by this rule, in this final rule RSPA 
is removing the 70 kl (18,500-gallon) exception for existing tank cars 
in current Secs. 173.314(c) and 173.323(c)(1).
    Further, while most commenters supported the 10-year modification 
program for existing tank cars, we agree with NTSB, that when these 
tank cars are used to transport Division 2.1 materials, a 5-year 
modification program (as proposed in Option B of the NPRM) will ensure 
that those cars presenting the greatest risk are modified first.
    Tank cars transporting materials in Division 2.2. A commenter 
stated that the proposal to require full-head protection for Division 
2.2 gases is sound and should be finalized. Several other commenters 
disagreed with the proposal to require full-head protection for 
Division 2.2 materials. The Reebie Associates report, submitted by CMA, 
identified 467 Class 2 materials affected by the proposed rule, 11 of 
which are Division 2.2 materials. The report shows that shippers used 
1,448 tank cars in 1992 to transport these Division 2.2 materials, as 
follows:

------------------------------------------------------------------------
                         Commodity                           Population 
------------------------------------------------------------------------
Argon, refrigerated liquid................................             2
Ammonia solutions.........................................            28
Bromotrifluoromethane.....................................             1
Carbon dioxide, refrigerated liquid.......................         1,016
Chlorodifluoromethane.....................................           145
Chlorotetrafluoroethane...................................            26
Chloropentafluoroethane...................................            37
Dichlorotetrafluoroethane.................................           164
Fertilizer, ammoniating solutions.........................             4
Trifluoromethane..........................................             1
Xenon, refrigerated liquid................................            24
                                                           -------------
    Total.................................................         1,448
------------------------------------------------------------------------

    CGA opposed the full-head protection requirement for tank cars 
transporting carbon dioxide. CGA referenced the testimony presented by 
RPI at the January 6, 1994 public hearing concerning recent head impact 
tests that verified the adequacy of the current head protection system 
on DOT 105A500W specification tank cars.
    With regard to CMA's and CGA's comments, RSPA and FRA believe that 
most tank cars used for ``carbon dioxide, refrigerated liquid,'' meet 
the performance standard for head protection by virtue of their tank 
head thickness and metal jacket. Tank cars used for ``argon, 
refrigerated liquid,'' and ``xenon, refrigerated liquid,'' also meet 
the head performance standard by virtue of the authorized class DOT 113 
tank car specification. These tank cars must have a minimum outer 
jacket tank head of not less than \1/2\-inch thick steel. See 
Sec. 179.400-8(d). A total of 1,042 tank cars, or 72 percent of the 
total Division 2.2 tank car population, are used to transport these 
three commodities.
    A commenter opposed tank-head protection for Division 2.2 materials 
stating, ``heavy walled tank and protective housing for the fittings is 
adequate for the transportation environment.'' The commenter also 
provided an in-house report using a computer model that claims the 
asphyxiation potential from a punctured Division 2.2 refrigerant gas 
tank car to be very low.'' Another commenter opposed applying head 
protection to tank cars transporting Division 2.2 refrigerant gases. 
This commenter stated that, in the past, DOT had judged a material 
based on its hazards under normal conditions of transport, and that in 
this rulemaking, DOT was over-assessing the potential for harm in a 
low-probability event. RPI supported full-head protection on new, 
insulated tank cars transporting Class 2 materials, but it opposed 
full-head protection for new non-insulated tank cars or for existing 
tank cars transporting these materials.
    We believe that even though the probability of an event occurring 
with these materials is low, safety concerns still need to be 
addressed, because the event may lead to high consequences, such as a 
large scale evacuation or an oxygen deficient atmosphere in a 
concentrated populated area. Taking the safety steps adopted in this 
final rule will mitigate these hazards.
    We also believe that the transportation risks associated with 
Division 2.2 gases are sufficient to require full-head protection for 
new tank cars, and for existing tank cars without head protection, when 
used to transport Division 2.2 materials. As noted above, this rule 
does not require existing tank cars equipped with half-head protection 
to be modified with full-head protection. RSPA and FRA are aware of 
industry concerns that the attachment of full-head protection to non-
jacketed cars is a feature not yet proven by long service. Similar 
arguments were raised when head protection was first required almost 
two decades ago [HM-144; 42 FR 46306, September 15, 1977]. FRA is aware 
of companies with plans to attach full-head protection to their non-
jacketed tank cars. As discussed later in this preamble, a phased-in 
10-year modification program is provided for existing tank cars.
    Existing tank cars without head protection. Most commenters to the 
NPRM supported the need to modify existing tank cars to meet the 
current safety requirements. One commenter supported the need to modify 
existing tank cars constructed from aluminum plate with half-head 
protection, but believed full-head protection should be required when a 
proven full-head shield design is available. Another commenter 
suggested that DOT should specifically recognize that tank cars used in 
``chlorine'' service meet the performance requirements for head 
protection and that DOT should not require any additional head 
protection for these tank cars.
    As stated in the NPRM, the benefits of head protection are real, 
predictable, and quantifiable. RSPA disagrees with commenters who state 
that full-head protection is not warranted. Where earlier rules 
required head protection on tank cars, it was a matter of recognizing 
the highest priority needs first. The question is not one of demanding 
low-priority, safety benefits, but the need to expand the safety base 
of hazardous materials transportation in tank cars. Further, the small 
additional cost of installing full-head protection on cars that now 
have no head protection system, as compared with adding only half-head 
protection, is justified on the basis of increased safety (see Chapter 
V of the Economic Impact Assessment and Regulatory Flexibility 
Analysis). In this final rule, RSPA requires existing tank cars that 
currently have no head protection, to have full-head protection 
installed when used to transport a Class 2 material. As explained 
below, RSPA is also requiring full-head protection for tank cars 
constructed from aluminum or nickel plate when used to transport 
hazardous material.
    Tank cars constructed from aluminum and from nickel plate. 
Commenters supported the need for head protection on tank cars 
constructed from aluminum or nickel plate, but not the full-head 
protection requirement proposed in the NPRM. Most commenters stated 
that there is no design available for the securement of full-head 
protection on tank cars without metal jackets. 

[[Page 49052]]

    One commenter stated that his company's new aluminum tank cars, 
constructed with greater tank shell and head dimensions than standard 
tank cars, offer greater protection without head protection. The 
commenter stated that further testing should be done and suggested that 
RSPA and FRA submit more evidence to support the need for this 
requirement.
    CMA supported requiring half-head protection for new tank cars 
constructed from aluminum or nickel plate, and requiring half-head 
protection for existing tank cars for certain hazardous materials. 
Several commenters requested that RSPA consider the characteristics of 
an individual Division 2.2 material, and that materials not subject to 
the HMR, and low hazard materials should be excluded.
    We realize that the use of good engineering practice and design 
specifications are needed to secure full-head protection to tank cars 
without metal jackets. Although there is no service experience for a 
full-head protection design on non-insulated tank cars, such designs 
are certainly not unreachable within the years ahead. In rulemaking 
proceedings under another docket [HM-144; 42 FR 46306, September 15, 
1977] introducing half-head protection, commenters offered similar 
arguments regarding head protection, for which solutions were later 
found as a result of technological innovation. Currently, FRA is aware 
of several companies that are nearing completion on their full-head 
protection designs for aluminum and nickel tank cars. We, therefore, 
believe that the introduction of this requirement will not adversely 
affect industry. In this final rule, the use of full-head protection 
for all tank cars constructed from aluminum or nickel plate is required 
when used to transport a hazardous material. As discussed later in this 
preamble, RSPA has provided for a phased-in 10-year modification 
program.

D. Thermal Protection Systems

    In the NPRM, RSPA proposed to require a thermal protection system 
for a Class 2 material when a thermal analysis of the tank car and 
lading shows that a release will occur other than through the safety 
relief valve when the tank car is subjected to either a 100-minute pool 
fire or a 30-minute torch fire. The current HMR require thermal 
protection for Division 2.1 (flammable gas) materials (with limited car 
capacity restrictions) and certain Division 2.3 (poison gas) materials. 
RSPA proposed to expand the thermal protection requirements to include 
Division 2.2 materials because, as stated by AAR, ``[a]t a chemical 
accident, there are generally two reasons for an evacuation, one is to 
protect the public from any toxic, poisonous, or noxious vapors or 
fumes generated by the product itself . . ., the second is to protect 
the public from thermal ruptures and the container debris that may be 
hurled from an incident site'' [Emergency Action Guides, p. VII]. RSPA 
also proposed to expand the thermal protection requirement to include 
all Division 2.3 materials.
    RSPA began to require the application of a thermal protection 
system on tank cars transporting Division 2.1 materials (flammable 
gases) or ``ethylene oxide'' (Division 2.3) after a series of major 
railroad accidents involving fires and ruptures of non-insulated 
pressure tank cars. The design of and criteria for thermal protection 
systems were based on tests performed by FRA at the U.S. Army 
Ballistics Research Laboratory in White Sands, New Mexico, and at the 
Transportation Test Center in Pueblo, Colorado. These tests revealed 
that a 127.2 kl (33,600 gallon) non-protected tank car filled with 
propane (Division 2.1) will rupture, with 40 percent of the lading 
remaining in the tank car, within 24 minutes after exposure to a pool-
fire. Rupture occurs when the residual strength of the tank shell falls 
below the force generated by the vapor pressure of the lading exerted 
on the inside surface of the tank shell. Further testing by FRA 
demonstrated that a tank car filled with propane and equipped with a 
thermal protection system delayed the thermal rupture of the tank car 
for 94.5 minutes, by maintaining the shell temperature low enough to 
vent 98 percent of the lading through the safety relief valve. The 
current performance standard, requiring exposure to a 100-minute pool 
fire and a 30-minute torch fire, was chosen because it provides 
emergency response personnel time to assess the accident and to 
initiate remedial actions, such as evacuating an area.
    Division 2.1 (flammable gas) and 2.3 (poisonous gas) materials: 
Several commenters supported the need for a thermal protection system 
on tank cars transporting Division 2.1 or 2.3 materials, regardless of 
tank car capacity. The AAR and another commenter supported a thermal 
protection system for all Class 2 materials, unless a shipper could 
show that a release will not occur, other than through the safety 
relief valve, when the tank and lading are subject to a fire. RPI also 
concurred on the need for thermal protection for all Class 2 materials, 
but, except for Division 2.1, but did not support the high-temperature 
performance standard proposed in Sec. 179.18. RPI stated that most 
insulation materials (e.g., 4 inches of glass-fiber insulation) are 
adequate.
    In this regard, RSPA stated in the NPRM that many insulation 
materials also provide good thermal protection. These insulation 
materials, when analyzed with the tank and the lading, may show that 
nothing further needs to be installed on the tank car to achieve 
passage of the pool- and torch-fire performance tests. Research 
sponsored by FRA on urethane-foam and glass-fiber insulation systems 
show that urethane-foam insulation will pass the pool- and torch-fire 
requirements and that glass-fiber insulation will also pass both tests, 
provided the insulation is held in place with a plastic or wire scrim. 
Owners of tank cars with either of these systems, or another comparable 
system, may find that their thermal analysis of the tank car shows the 
presence of sufficient thermal protection to meet the performance 
standard. In this case, the tank car owner would have to verify only 
that the insulation material installed on the tank car is capable of 
passing the pool- and torch-fire verification or ``proof'' tests in 
Appendix B to Part 179 of this final rule. Owners may find that a tank 
car will pass the performance standard with only minor modifications, 
such as applying a thermal protection system to the manway nozzle.
    Also in the NPRM, RSPA stated that, in 1981, a joint effort between 
the Chlorine Institute and RPI-AAR Tank Car Safety Research and Test 
Project resulted in the development of an insulation system to protect 
a chlorine tank car involved in a fire. The insulation system developed 
maintains back plate (inside surface of the tank car shell) 
temperatures below 250.56  deg.C (483  deg.F). After reviewing the 
thermal resistance capabilities of the insulation system used on 
chlorine tank cars, RSPA incorporated it into the HMR in 1987. Readers 
should refer for more information to Docket HM-166U, entitled 
``Transportation of Hazardous Materials; Miscellaneous Amendments'', 52 
FR 13034, (April 20, 1987).
    Division 2.2 (nonflammable gas) materials. As noted earlier in the 
preamble discussion on tank-head protection for Division 2.2 materials, 
CMA commented that there were 1,448 tank cars allocated to Division 2.2 
materials that had not already been captured in another service, such 
as PIH. Of those, ``argon, refrigerated liquid,'' ``carbon dioxide, 
refrigerated liquid,'' and ``xenon, refrigerated liquid,'' represent 
1,042 tank cars, or 72 percent. CMA further commented that 

[[Page 49053]]
almost 100 percent of the total would need retrofitting and that the 
overall economic impact of the new regulations on this group of tank 
cars amounts to $26.0 million for retrofitting and $2.59 million for 
higher lease rates and additional cars in the tenth year of the 
implementation period.
    With regard to the issues raised by CMA, this final rule does not 
contain any new thermal protection requirements for ``argon, 
refrigerated liquid,'' ``carbon dioxide, refrigerated liquid,'' or 
``xenon, refrigerated liquid.'' Carbon dioxide is transported in DOT 
105A500W tank cars equipped with two regulator valves, a reclosing 
pressure-relief device, a frangible disc, and an insulation system with 
good thermal performance (a thermal conductance of 0.03 British Thermal 
Units [B.t.u.] per square foot per degree Fahrenheit differential). 
Consequently, existing and new tank cars in carbon dioxide service have 
sufficient thermal resistance when exposed to fire. Likewise, because 
with argon and xenon, refrigerated liquids are packaged under the 
exceptions for atmospheric gases in Sec. 173.320, this final rule does 
not impose any new thermal protection requirements. This section 
exempts cryogenic atmospheric gases from the packaging requirements 
when the packagings are designed to maintain pressures below 1.74 Bar 
(25.3 psi) under ambient temperature conditions.
    Another commenter opposed the use of thermal protection for 
Division 2.2 materials on the basis that the hazards they pose do not 
equate to those of Division 2.1 and 2.3 materials. The commenter 
further stated that the thermal protection requirements proposed for 
Division 2.2 materials do not appear to be justified by the hazards 
posed, because, in many cases, these materials dissipate naturally with 
little risk to the surroundings.
    A commenter, primarily addressing refrigerant gases, noted that an 
analysis of each Division 2.2 material, to predict the behavior of a 
tank car in a 100-minute pool-fire, seemed an unnecessary precaution 
because the calculations, required by the current regulations, for 
sizing safety relief valves accomplish the same purpose and meet this 
same standard. RSPA and FRA disagree with this commenter's position 
that the current regulations for sizing safety relief valves accomplish 
the same purpose as the proposed Division 2.2 thermal protection 
performance standard. The current safety relief valve-sizing 
requirements make several assumptions. First, the valve sizing formula 
assumes the exposure factor, that portion of the tank car exposed to 
fire (represented as A0.82), is about one-fourth of the tank. The 
pool-fire computer model in this final rule assumes total engulfment. 
Second, the safety relief valve sizing formula assumes that flame 
temperatures will reach approximately 650  deg.C (1,200  deg.F.). The 
pool-fire standard assumes flame temperatures will reach 871  deg.C 
(1,600  deg.F) for a pool-fire and 1,204  deg.C (2,200  deg.F) for a 
torch fire at 40 miles per hour.6 Third, the safety relief valve-
sizing formula does not take into consideration either an overturned 
tank car venting liquid or a liquid-gas mixture (two phase flow) or the 
diminished burst strength of the heated tank shell in the non-wetted 
area, after prolonged fire exposure.

    \6\The pool-fire computer model assumes an average heat flux 
over the entire tank surface, equivalent to complete engulfment in a 
fire, where the flame temperature is 815.5  deg.C (1,500  deg.F). If 
a higher or lower flame temperature were assumed, the parametric 
analyses in the computer model would not match the actual field test 
data.
---------------------------------------------------------------------------

    The Fertilizer Institute did not support the requirement for 
thermal protection on tank cars transporting ``anhydrous ammonia''. It 
stated that the likelihood of a fire-induced rupture of a tank car 
carrying anhydrous ammonia has significantly decreased since 1980 
because of added safety devices, safer placement in trains, and 
improved emergency response procedures. Thus, there is little, if any, 
increase to public safety by imposition of the proposed thermal 
protection requirements on these tank cars.
    While RSPA and FRA agree with The Fertilizer Institute that the 
safety record for tank cars transporting ``anhydrous ammonia'' is good, 
these cars have a potential for violent rupture similar to compressed 
gas tank cars, which received thermal protection many years ago. As The 
Fertilizer Institute notes, the threat of a fire-induced violent 
rupture of an anhydrous ammonia tank car is more than just a 
theoretical potential. Since 1990, according to figures from the AAR, 
``anhydrous ammonia'' has been the sixth highest volume hazardous 
material transported by railroad.
    AAR and two other commenters supported the need for thermal 
protection for Class 2 materials, including Division 2.2. One of these 
commenters stated: ``thermal protection systems are a good, simple idea 
whose time has come. The purpose of the system is to prevent rupture of 
the tank car in a fire with the release of its hazardous materials 
contents to the environment. Uncontrolled release of almost any 
hazardous material to the environment is objectionable whether due to 
toxicity, flammability, or simply clean-up costs.'' This commenter 
further stated that there can be little basis for exempting anhydrous 
ammonia from the thermal protection requirements simply because it is 
not likely to catch fire once released. Its PIH characteristic remains, 
and the potential for rupturing in a non-insulated tank car is high.
    Although not all commenters agree on the need for thermal 
protection for Division 2.2 materials, in this final rule RSPA requires 
such a system if, after an analysis of the effects of a 100-minute pool 
fire and a 30-minute torch fire, there will be a release of the tank 
car lading other than through the safety relief valve. Because tank 
cars may transport different ladings, and because changing ladings may 
affect the whole system, owners or shippers may choose to perform a 
``worst case'' analysis based on all the commodities the car is likely 
to carry.7

    \7\Owners are reminded that 49 CFR 173.31(a)(4) limits the use 
of tank cars to those commodities for which they are authorized. 
Authorized (or approved) commodities are those listed on the 
certificate of construction or an AAR R-1 form. (See the AAR 
Specifications for Tank Cars Section 1.4.3.1 and Appendix R, Section 
R4.04.)
---------------------------------------------------------------------------

    Based on these comments and FRA's research, this final rule 
requires the owner or the shipper of a Class 2 material, with the 
exception of ``carbon dioxide, refrigerated liquid,'' ``chlorine,'' and 
``nitrous oxide, refrigerated liquid'' as explained above, to perform 
an analysis of the characteristics of the material and of the thermal 
resistance capabilities of the tank car, taking into consideration the 
safety relief valve start-to-discharge pressure setting and relief 
capacity and all areas of the tank car that are not afforded protection 
from fire (such as stub sills, bolsters, and protective housings).
    Tank cars constructed from aluminum and nickel plate. Most 
commenters said that the lading within a tank car constructed from 
aluminum or nickel plate should determine the need for a thermal 
protection system.
    We agree. The NPRM proposed to require a thermal protection 
analysis for aluminum and nickel plate cars carrying Class 2 materials. 
Based on the comments received, we believe that all such tank cars will 
need protection and that such protection is essential.
    This final rule requires the owner of an aluminum or nickel plate 
tank car used to transport a Class 2 material to perform an analysis of 
the tank car in a 100-minute pool fire and in a 30-minute torch fire 
using FRA's Tank Car Fire model. If the analysis shows that a release 
of the lading from the tank car, 

[[Page 49054]]
will occur, other than through the safety relief valve, a thermal 
protection system will be required. This final rule adopts a 10-year 
phase-in period for those existing tank cars required to have thermal 
protection.

E. Shell Protection

    For tank cars transporting of a material poisonous by inhalation 
(PIH), RSPA proposed that they have ``shell protection conforming to 
Sec. 179.100-4.'' That is, the optional use of an insulated DOT 105S 
tank car or a non-insulated, but thermally protected, DOT 112J or 114J 
tank car having a metal jacket. Although RSPA used the term ``shell 
protection'' to identify these systems, the intent of the NPRM was to 
require tank cars transporting a PIH gas (Division 2.3) to conform to 
the same requirements as tank cars transporting a PIH liquid. For a 
complete discussion, see Performance-Oriented Packaging Standards; 
Miscellaneous Amendments, Docket HM-181F, 58 FR 50224 (September 24, 
1993). In the final rule issued under that docket, RSPA authorized the 
optional use of an insulated DOT 105S tank car or a non-insulated, but 
thermally protected, DOT 112J or 114J tank car for poisonous liquids 
having a PIH hazard.
    In its comments to the NPRM, one commenter supported the need for 
shell protection for PIH materials. Another commenter suggested that, 
in lieu of a metal jacket, RSPA should establish a performance 
standard, as with thermal and head protection. Until a performance 
standard is established, shell-protection resistance should be 
equivalent to a tank car having a tank test pressure of 20.7 Bar (300 
psi) constructed from carbon steel and with a 1/8-inch carbon steel 
jacket. The commenter stated that the shell-puncture resistance should 
be based on either a total metal thickness, or an approved calculation. 
We agree with this commenter that a performance-based standard for 
shell-puncture resistance may have merit over specification-based 
standard adopted in this final rule. However, such performance based 
standards have not been proposed.
    Another commenter opposed the use of a metal jacket on pressure 
tank cars transporting a PIH material on the basis that the FRA's 
proposal did not support the conclusion that jacketing improves 
puncture resistance. The commenter further questioned the use of a tank 
jacket over thicker tank shells, since ``jackets provide thermal not 
puncture protection.''
    In response to similar remarks, RSPA discussed in the NPRM a 1987 
RPI report on the vulnerability of pressure tank car shells to 
puncture.8 RPI found that shelf couplers, hardboard insulation 
(cork), increased shell thickness, thermal protection, small tank car 
size and increased jacket thickness proved effective towards reducing 
the frequency of shell punctures. The RPI report summarizes a 20\1/2\-
year history of accident data on shell punctures of pressure tank cars 
and concludes that the 11-gauge steel jacket provides a measure of 
shell protection. In addition to RPI's report, FRA also found, in a 
research contract awarded to the AAR, that puncture resistance is 
strongly influenced by impact location, by head and jacket thickness 
and by insulation thickness.9

    \8\Phillips, E.A., Review of Pressure Car Shell Puncture 
Vulnerability, RA-09-6-52, (1987), AAR-RPI Railway Tank Car Safety 
Research and Test Project, AAR Technical Center, Chicago, Illinois.
    \9\[Coltman, M., & Hazel, M., Jr., Chlorine Tank Car Puncture 
Resistance Evaluation, (1992) Federal Railroad Administration, 
Washington, D.C. (NTIS DOT/FRA/ORD-92/11).
---------------------------------------------------------------------------

    RSPA explained earlier, in Docket HM-181, that the purpose of a 
metal jacket is to provide ``both accident damage and fire protection'' 
for certain [liquid] PIH materials.10 This final rule expands that 
philosophy to all PIH materials [including compressed gases] and 
authorizes the use of an insulated class DOT 105S tank car or a non-
insulated, but thermally protected, class DOT 112J or 114J tank car.

    \10\See the final rule on Performance-Oriented Packaging 
Standards; Miscellaneous Amendments, Docket HM-181F, 58 FR 50224 
(September 24, 1993), and the NPRM, 58 FR 37612 (July 12, 1993).
---------------------------------------------------------------------------

F. Self-Energized Manways Located Below the Liquid Level of the Lading

    RSPA proposed in the NPRM to prohibit the use on tank cars of a 
self-energized manway located below the liquid level of the lading. The 
proposal was based on a September 8, 1987 railroad yard incident in New 
Orleans, Louisiana.11 In this incident, a tank car equipped with a 
self-energized bottom manway and loaded with butadiene developed a leak 
and caught fire. At one point during the incident, the flames were 
large enough that both spans of a bridge on Interstate 10 were 
engulfed. After the investigation, NTSB concluded that ``it is unlikely 
that a hazardous material leak through a bottom manway during 
transportation could be stopped.'' NTSB urged FRA to prohibit the 
transportation of tank cars that have a manway opening located below 
the liquid level of the lading in hazardous materials service. Because 
the design of bottom manways depends in part on the weight of the 
product and the pressure in the tank to make the seal fully effective, 
this type of closure system becomes vulnerable to releasing product 
when the lading is displaced within the tank. Therefore, we agree with 
NTSB's conclusion.

    \11\Butadiene Release and Fire from GATX 55996 at the CSX 
Terminal Junction Interchange, New Orleans, Louisiana, September 8, 
1987, National Transportation Safety Board Report NTSB/HZM-88/01, 
National Transportation Safety Board, Washington, D.C.
---------------------------------------------------------------------------

    In its comments to the NPRM, the AAR, RPI, and several other 
commenters supported the proposal to remove self-energized manways 
located below the liquid level of the lading. A commenter stated that 
their design incorporates an externally elliptically shaped ring clamp 
which is bolted to the manway closure plate with numerous closely-
spaced studs around the circumference of the ring. This commenter holds 
two DOT exemptions (DOT-E 5493 and DOT-E 6117) to operate tanks cars in 
hydrogen sulphide service with this design. RSPA and FRA believe that 
this design is certainly preferable to that used on the car that leaked 
and burned in New Orleans and is similar to a more conventional 
external flange, however, we believe this design still remains a 
potential source of leaks since it is located below the liquid level of 
the lading. Based on these reasons, RSPA will grant the exemption 
holder a reasonable amount of time to phase out the use of these tank 
cars.
    While some commenters agreed with a 2-year phase out program of 
self-energized manways, NTSB stated that RSPA should immediately 
prohibit such manways, and the AAR suggested a one-year phase-out 
program.
    Based on these comments, this final rule prohibits the construction 
of new tank cars having an internal self-energized manway located below 
the liquid level of the lading. This prohibition is added in 
Sec. 179.103-5. Based on NTSB's comments, compliance with this 
provision is required beginning on the effective date of this final 
rule.

G. Non-Pressure Tank Cars for Materials Poisonous by Inhalation

    In the NPRM, RSPA proposed to prohibit the use of non-pressure tank 
cars (e.g., class DOT 111A) for materials poisonous by inhalation.
    In a recent research report, FRA found that, in a single-car 
national risk profile, the transportation of ethylene oxide in a DOT 
111A100W4 tank car involves significantly greater risk than 
transportation of the same material in a 

[[Page 49055]]
DOT 105J500W tank car.12 Characteristics and parameters evaluated 
in this assessment included the toxicity, fire hazard, and explosion 
hazard. In comments to the ANPRM, RPI reported that, during the time 
period of 1965 through 1986, class DOT 111A tank cars involved in 
accidents and damaged were slightly more than three times as likely to 
lose lading as were class DOT 105 cars in similar situations.13

    \12\Raj, P.K., and Turner, C.K., Hazardous Materials 
Transportation In Tank Cars/Analysis of Risks--Part 1, NTIS DOT/FRA/
ORD-92/34, (1993), Federal Railroad Administration, Washington D.C.
    \13\Phillips, E.A., Analysis of Tank Cars Damaged in Accidents 
1965 through 1986, RA-02-6-55, (1989), AAR-RPI Railway Tank Car 
Safety Test and Research Project, AAR Technical Center, Chicago, 
Illinois.
---------------------------------------------------------------------------

    The Raj/Turner report amply demonstrates (and AAR/RPI Tank Car 
Safety Test and Research Project data support) that it is 
``improbable'' to assume that any single tank car (e.g., DOT 111A or 
DOT 105) would be involved in an accident. However, based on FRA 
accident data referenced earlier regarding DOT 111A and DOT 105 tank 
cars, a significant number of such cars will be involved in accidents 
during their service life.
    Several commenters supported disallowing the use of non-pressure 
tank cars for the transportation of PIH materials. Because of the 
hazards associated with PIH materials and the performance superiority 
of the so-called ``pressure'' tank cars for this service, RSPA agrees 
with the commenters. This final rule removes the class DOT 111A tank 
car as an authorized packaging for Division 2.3 materials on the 
effective date of this final rule.

H. Phasing Out of Various ``Grandfather'' Provisions

    In the NPRM, RSPA proposed to remove from the HMR several 
grandfather provisions that affect tank cars. The grandfather 
provisions allow tank cars built before a certain date to remain in 
service without modification. As an example, in Sec. 173.314(c), Notes 
23 and 24 allow the continued use of class DOT 105A tank cars for 
certain compressed and flammable gases if they were built before 
September 1, 1981, while tank cars built after that date must meet a 
more stringent class DOT 105S or 105J standard.
    NTSB stated, in a March 1, 1988 letter to RSPA, that tank cars 
failing to meet current minimum safety requirements should no longer be 
used for transportation of hazardous material under grandfather 
provisions. NTSB stated that these grandfather provision could result 
in a reduced level of safety. The AAR also petitioned RSPA to amend 
Sec. 173.314(c) Note 30 (P-1138), stating that it does not provide any 
assurance that tank cars with head protection will be used for PIH gas 
service in the foreseeable future because companies will be able to use 
tank cars without head protection for PIH compressed gas service for 
the next 30 years. Other commenters agreed that the grandfather 
provisions proposed for removal in the NPRM are no longer compatible 
with the needs of safety.
    Based on these comments, RSPA is removing certain grandfather 
provisions. In Sec. 171.102, special provision ``B63'' is removed to 
disallow the use of DOT 105A100W, 111A100W4, 112A200W, and 114A340W 
tank cars for ``ethyl chloride'' and ``ethyl methyl ether.'' Prior to 
the issuance of Docket HM-181, these two materials were classed as 
flammable liquids. Because these tank cars do not have head protection 
or thermal protection systems, they do not provide an equivalent level 
of safety compared to other tank cars used for Division 2.1 materials. 
Also, special provision ``B63'' is removed from column 7 of the 
Sec. 172.101 table entries for these two hazardous materials, thereby 
prohibiting the use of non-protected tank cars.
    Other changes are made to disallow the use of class DOT 111A non-
pressure tank cars for Class 2 (compressed gas) materials, such as 
``ammonia solutions,'' ``ethylamine,'' ``ethyl chloride,'' and ``ethyl 
methyl ether.'' This final rule also removes the DOT 111A100W4 car as a 
packaging for ``ethylene oxide'' in Sec. 173.323(c)(1).

I. Bottom-Discontinuity Protection for Bottom Outlets

    In the NPRM, RSPA proposed to require bottom-discontinuity 
protection (e.g., for bottom outlets) on tank cars. The proposed 
requirements were intended to simply adopt the requirements published 
by the AAR. In July of 1979, the AAR required bottom-discontinuity 
protection for new tank car construction. Over a period of years, these 
requirements were extended to existing tank cars on a priority schedule 
determined by the nature of the commodity transported. The AAR's 
program for bottom-discontinuity protection consists of either a metal 
``skid'' protecting the portion of the bottom outlet that protrudes 
beyond the shell or the machining of a ``breakage groove'' in the valve 
assembly.
    AAR, the Chlorine Institute, CMA, and several other commenters 
supported the adoption of bottom-discontinuity protection for tank 
cars, provided such protection was consistent with the AAR 
requirements. API asked RSPA to clarify the requirements for bottom-
discontinuity protection in this final rule. API and several other 
commenters stated that the proposed rule would require the modification 
of a number of tank cars, built before July 1, 1979, because most were 
modified according to Appendix Y and not paragraphs E9.00 or E10.00 of 
the AAR Specifications for Tank Cars. Appendix Y permits three levels 
of protection for allowing the types of discontinuity: bottom outlets 
that extend 1 inch or more; blind flanges and washouts that extend 2 
and \5/8\ inches or more; and sumps and internally closed washouts that 
extend 5 inches or more. Paragraphs E9.00 and E10.00 generally require 
the protection of each valve and fitting from mechanical damage by the 
tank, an another protective device, or the underframe.
    Several other commenters stated that the proposed rule would also 
require the modification of all existing tank cars, including those 
that do not transport hazardous materials. The Sulphur Institute and 
another commenter opposed the need to add bottom-discontinuity 
protection to existing tank cars that transport sulfur, molten, 
claiming that such protection has little practical benefit.
    In the public hearing held on January 6, 1994, in Washington, D.C., 
FRA stated that it was not the Department's intention to require the 
modification of previously modified tank cars, nor to require bottom-
discontinuity protection for tank cars that transport materials not 
subject to the HMR.
    In this final rule, RSPA requires bottom-outlet protection that 
conforms to paragraphs E9.00 and E10.00 of the AAR Specifications for 
Tank Cars, M-1002, for all new tank cars equipped with bottom unloading 
devices. Existing tank cars, without bottom-discontinuity protection, 
used for the transportation of hazardous materials must conform to the 
above paragraphs no later than 10 years after the effective date of 
this final rule. Existing tank cars that conform to the bottom-
discontinuity protection requirements of Appendix Y of the AAR 
Specifications for Tank Cars, M-1002 may continue in use after the 
effective date of this final rule. This final rule does not require the 
modification of existing tank cars that transport materials not subject 
to the HMR.

J. Protective Coatings on Insulated Tank Cars

    In the NPRM, RSPA proposed use of protective coatings on the 
exterior of a 

[[Page 49056]]
tank car and the interior of a tank car jacket to retard rust or 
corrosion. The proposal was in response to an AAR petition (P-1050) and 
FRA's findings of severe corrosion or pitting on the outer surface of 
the tank shell, or the inner surface of the tank jacket, of insulated 
tank cars. It is not known whether the corrosion stems from the 
physical properties of the insulation itself or whether the corrosion 
develops when insulation becomes impregnated or contaminated with water 
or a chemical from the atmosphere in which the tank car operates. 
Research within the industry has led to the development of protective 
coating materials.
    Most commenters supported the proposal. One commenter stated that 
acid-resistant protective coatings should be applied. The commenter 
further stated that several manufacturing and repair shops are using 
non-acid resistant latex coatings under polyurethane-foam insulations. 
Another commenter suggested that the rule should be clarified to 
exclude tanks or jackets manufactured with self-protective materials 
such as stainless steel. Still another commenter asked RSPA to consider 
adopting a recommended practice for applying protective coatings on 
tank cars that is now under development by the National Association of 
Corrosion Engineers.
    With regard to these comments, this final rule simply modifies 
Secs. 179.100-4 and 179.200-4 by removing the exception for 
polyurethane-foam insulations. Each of the current sections, and the 
proposed rule, only require a protective coating on a carbon steel tank 
shell and tank jacket. Concerning the comment on acid-resistant 
coatings, RSPA agrees that applied coatings should prevent any 
corrosive attack to the tank metal. RSPA and FRA will explore, in 
cooperation with the AAR, CMA, and RPI, the need for and development of 
acid-resistant coating standards.
    NTSB commented that the proposed rule does not sufficiently address 
the potential problem of existing tank cars. NTSB further noted that a 
requirement to apply a protective coating on an existing tank car, only 
when the jacket is removed to repair a tank, cannot ensure that 
corrosion problems will be detected before the tank corrodes through 
and releases its lading. NTSB stated that, at a minimum, tank cars 
currently in use without protective coatings should be inspected 
periodically for corrosion damage and tank cars found with corrosion 
damage should be required to have appropriate repairs.
    We agree with NTSB, and in this final rule require, under Docket 
HM-201, new inspection intervals for materials that are corrosive to 
the tank and a thickness performance measurement to ensure that the 
tank shell is not corroded below the minimum shell thickness as 
prescribed by the AAR. RSPA and FRA believe that HM-201 is responsive 
to NTSB's concerns.
    In this final rule, RSPA is requiring protective coatings for all 
new tank cars and for existing tank cars when a repair to the tank car 
requires the complete removal of the jacket, as suggested by 
commenters.

K. Halogenated Organic Compounds (HOC)

    To address a 1991 NTSB safety recommendation,14 RSPA proposed 
in the NPRM to require the use of a tank car with enhanced puncture 
resistance if the tank is used to transport one or more of the 100 HOC 
compounds listed in 40 CFR Part 268 Appendix III. The Appendix III list 
was developed by EPA pursuant to statute (42 U.S.C. 6924) in order to 
prohibit the land disposal of certain compounds having a carbon-halogen 
bond, and that have the potential to harm human health and the 
environment (these EPA compounds were identified as the ``California 
List'' under the statute [See also 40 CFR 268.32]).

    \14\Transportation of Hazardous Materials by Rail, National 
Transportation Safety Board Safety Study, Report NTSB/SS-91/01, 
National Transportation Safety Board, Washington, D.C. (Safety 
Recommendations R-91-11 and R-91-12).
---------------------------------------------------------------------------

    Many commenters opposing regulation of the EPA compounds suggested 
that RSPA should continue to only regulate the compounds identified as 
hazardous substances in Appendix A to Part 172. Commenters further 
suggested that DOT should not consider the HOC concentration threshold 
for those compounds. Several commenters stated that the regulatory 
action proposed by RSPA is unnecessary, that RSPA should discontinue 
its efforts to regulate these EPA compounds, and that RSPA should not 
consider extending enhanced tank car standards to those carrying the 
more than 1,000 chemicals prohibited from land disposal.
    API, CMA, and several other commenters suggested that the threshold 
quantities for the EPA compounds are too low for transportation 
purposes. The EPA threshold in 40 CFR 268.32 is 1,000 milligrams per 
liter (mg/l) for liquids and 1,000 milligrams per kilogram (mg/kg) for 
solids.
    CMA furnished a benefit/cost analysis, prepared by Reebie 
Associates, that used 1992 TRAIN II data; thereby updating the previous 
work performed by AAR, CMA, and RPI addressed in the NPRM. The CMA 
report shows that a total of 3,893 tank cars transported an EPA 
compound. CMA's list and the number of tank cars used for such 
compounds follows:

------------------------------------------------------------------------
                                 AAR/CMA/RPI                            
    Hazardous      CMA's 1992     agreement   Currently in              
   substances      population     (based on     pressure      Remaining 
                                 1988 data)     tank cars               
------------------------------------------------------------------------
1,1-                                                                    
 Dichloroethylen                                                        
 e..............             1  ............  ............             1
1,2-                                                                    
 Dichloroethane.           236           236  ............  ............
1,2-                                                                    
 Dichloropropane            31  ............  ............            31
Carbon                                                                  
 tetrachloride..           312           312  ............  ............
Chlordane.......            10  ............  ............            10
Chlorobenzene...           105           105  ............  ............
Chloroethane                                                            
 (ethyl                                                                 
 chloride)......           106  ............           106  ............
Chloroform......           227           227  ............  ............
Chloropropene...             7  ............  ............             7
CIS 1,3-                                                                
 dichloropropane            42  ............  ............            42
Dichlorodifluoro                                                        
 methane........           224  ............           224  ............
Dichlorofinrorom                                                        
 ethane.........             2  ............  ............             2
Dichlorofluorome                                                        
 thane..........             1  ............  ............             1
Hexachlorocyclop                                                        
 entadiene......             8  ............             8  ............

[[Page 49057]]
                                                                        
Methylene                                                               
 chloride.......             2             2  ............  ............
o-                                                                      
 Dichlorobenzene            15            15  ............  ............
p-                                                                      
 Dichlorobenzene            82            82  ............  ............
Pentachloropheno                                                        
 l..............            10  ............  ............            10
Tetrachloroethan                                                        
 e..............            13            13  ............  ............
Trichlorobenzene             6  ............  ............             6
Trichloromonoflu                                                        
 oromethane.....             4  ............             4  ............
Vinyl chloride..         2,449  ............         2,449  ............
                 -------------------------------------------------------
    Totals......         3,893           992         2,791           110
------------------------------------------------------------------------



    Commenters stated that RSPA should not include materials that are 
transported as a solid because, when released, the clean up of these 
materials is easily achieved. This statement assumes that accidents 
will not occur near lakes, rivers or streams, or that rainfall will not 
carry solid residue to such water sources. It is RSPA's and FRA's 
experience that these types of accidents can occur as evidenced by the 
metam sodium spill in the Sacramento River in California.
    As discussed in the NPRM, these materials were also evaluated by 
the AAR in an effort to identify materials that have the potential to 
harm human health and the environment. The AAR analyzed the EPA 
compounds using a computer model based on EPA and standard chemical 
dispersion equations. The AAR model describes a method of evaluating 
the relative environmental hazard of chemicals shipped in tank 
cars.15 In addition to the computer model, the AAR surveyed the 
railroad industry for the clean-up costs associated with a spill of an 
EPA compound. The AAR considered in their analysis: (1) Compounds that 
were permitted in non-pressure tank cars by the DOT in 1988; (2) at 
least one shipment of the compound reported to TRAIN II16 in 1988; 
(3) the compounds with an EPA reportable quantity (RQ) of less than 
1,000 pounds in 1988; (4) the compounds prohibited from land disposal 
by the EPA; and (5) the compounds suggested by the railroads' hazardous 
materials or environmental staff, or the AAR contractor on the project. 
The results of the 1988 survey identified 10 compounds, transported in 
class DOT 111A tank cars at that time, that pose a potential threat to 
human health and the environment. These compounds were:

    \15\Lowenbach, William, A., Consequence Models of Hazardous 
Materials Releases on Railroads, Association of American Railroads 
(1989), Washington, D.C.
    \16\The Association of American Railroads (AAR) data network, 
Tele-Rail Automated Information Network (TRAIN II), collects 
information on approximately 90 percent of the rail traffic 
originating and terminating in the United States. Users of the 
network can trace individual car movements or gather information on 
a particular cargo moving by rail. The AAR uses the data to develop 
statistical trends in both car movement and commodity flow.

Carbon tetrachloride
Chlorobenzene
Chloroform
Dichlorobenzene
Ethylene dibromide (1,2-Dibromomethane)
Ethylene dichloride (1,2-Dichloroethane)
Methyl chloroform (1,1,1-Trichloroethane)
Methylene chloride (Dichloromethane)
Perchloroethylene (Tetrachloroethene)
Trichloroethylene (Trichloroethene)

    The results of AAR's analysis show that, within the last 10 years, 
the release of these compounds in railroad accidents has resulted in 
environmental clean-up costs exceeding $50 million. Even though these 
materials accounted for less than one percent of the total volume of 
hazardous materials, their releases accounted for 60 percent of all 
railroad environmental clean-up costs. Based on the results of the 
analysis, the AAR, CMA, and RPI have agreed that by January 1, 2000, 
these 10 compounds should be transported only in a DOT 105S200W or a 
DOT 112S200W tank car manufactured from AAR TC-128 normalized steel. 
One of the 10 compounds, ``ethylene dibromide,'' is a compound that is 
poisonous by inhalation (Zone B).
    As shown by CMA, 3,893 tank cars were used to transport these ``EPA 
compounds''; of that total, ``chloroethane,'' 
``dichlorodifluoromethane,'' ``hexachlorocyclopentadiene,'' 
``trichloromonofluoromethane,'' and ``vinyl chloride'' represent 2,791 
tank cars, or 72 percent of the total. Because the packaging 
authorizations for these compounds currently require the use of classes 
DOT 105J, 112J, 112T, 114J, 114T tank cars, these tank cars currently 
meet the proposed standard.
    As noted above, AAR, CMA, and RPI agreed to use only DOT 105S200W 
and 112S200W (or better) tank cars: These compounds are transported in 
992 dedicated tank cars. CMA identified an additional 110 tank cars 
that are used to transport an EPA compound, but lie outside of the 
industry agreement. Because these 110 additional tank cars represent a 
potential risk to human health and the environment, RSPA believes it is 
reasonable to require the same level of protection for the additional 
tank cars identified by CMA, based on the 1992 TRAIN II data, as those 
identified by the AAR, CMA, and RPI, based on the 1988 TRAIN II data. 
It simply cannot be argued that the shipment of an EPA compound 
identified after 1988 poses less risk in transportation than if the EPA 
compound would have been identified by the AAR, CMA, and RPI in 1988. 
Furthermore, because the AAR, CMA, and RPI agreement does not preclude 
the use of a non-protected tank car in transportation by any one member 
or nonmember of the agreement, such cars may still be used.
    After considering each of the comments, RSPA agrees it should only 
regulate those EPA compounds listed in the HMR. After reviewing the 100 
EPA compounds (listed in 40 CFR 268 Appendix III), RSPA found that all 
but 16 of the compounds are currently identified as a hazardous 
substance. The 16 compounds are:

Bis(2-chloroethoxy)ethane
Bis(2-chloroethyl)ether
Bromomethane
2-Chloro-1,3-butadiene
3-Chloropropene
1,2-Dibromomethane
Dibromomethane
Hexachlorodibenzo-p-dioxins
Hexachlorodibenzofuran
Iodomethane
Methylene chloride
Pentachlorodibenzo-p-dioxins 

[[Page 49058]]

Pentachlorodibenzofuran
Tetrachlorodibenzofuran
Tribromomethane
1,2,3-Trichloropropane

More than 30 of the compounds are listed by proper shipping name in the 
Sec. 172.101 Table. As a group, the EPA compounds include: volatiles 
(35 compounds); semivolatiles (33 compounds); organochlorine pesticides 
(20 compounds); phenoxyacetic acid herbicides (3 compounds); PCBs (all 
PCBs); and dioxins and furans (7 compounds).
    Based on this review, this final rule requires that, when the EPA 
compounds listed in the HMR are transported in large capacity tank 
cars, the tank cars must conform to a limited and designated 
specification with greater protection in accidents. Also, to ensure the 
proper identification and packaging of these materials, RSPA is listing 
(with the exception of Class 2 materials [compressed gases], PIH 
materials, and the 16 materials not now identified as hazardous 
substances) in Sec. 173.31(f), all EPA compounds listed in 40 CFR Part 
268, Appendix III. As explained elsewhere in the preamble, RSPA is no 
longer authorizing Class 2 materials or PIH materials in low-pressure 
tank cars, e.g., class DOT 111A.
    Because RSPA is listing the EPA halogenated-organic compounds as 
hazardous substances, in this final rule, the threshold quantity is the 
reportable quantity of the hazardous substance. As an example, if the 
material in the tank car (including its mixtures and solutions) (1) is 
listed in Appendix A to Sec. 172.101, (2) is in a quantity that equals 
or exceeds the reportable quantity (RQ) of the material listed in 
Appendix A, and (3) is listed in Sec. 173.31(f), it must be transported 
in a tank car of limited and designated specification to offer greater 
protection in the event of an accident.
    In the NPRM, RSPA proposed that any of the halogenated organic 
compounds identified by EPA must be transported in a tank car meeting 
DOT 105S200W, DOT 112S200W with an 11-gauge metal jacket, or DOT 
112S340W without a metal jacket. RSPA stated that the metal jacket and 
head protection on these tank cars blunt the impacting forces from 
couplers, wheels, track, and other objects along the carrier's right-
of-way. According to FRA research, this blunting effect is directly 
proportional to the thickness of the tank jacket or head shield and is 
effective in preventing tank punctures.17 The NPRM would have 
allowed the use of any class DOT 105 or DOT 112 tank car regardless of 
its date of construction. Older tank cars would be allowed, including 
those constructed with an older steel specification, such as ASTM A212 
Grade B. Because the older steels have less puncture resistance than 
the steels currently in use, the NPRM proposed the use of an external 
metal jacket to help blunt any impacting force, as a result of an 
accident, to the tank shell.

    \17\Coltman, M., & Hazel, M., Jr., Chlorine Tank Car Puncture 
Resistance Evaluation, Report DOT/FRA/ORD-92-11, Federal Railroad 
Administration (1992), Washington, D.C.
---------------------------------------------------------------------------

    At the January 6, 1994, public hearing, a commenter asked RSPA to 
consider the use of a non-jacketed DOT 112S200W tank car, provided that 
the tank car was constructed from an AAR normalized high-strength steel 
specification, AAR TC-128. This steel specification has high tensile 
and yield strength. In addition to the higher tensile and yield 
strengths, commenters stated that normalization of the steel adds extra 
puncture resistance. A commenter further stated that a tank car 
constructed from the AAR's TC-128 steel specification would provide a 
level of puncture resistance comparable to that of tank cars proposed 
for use in the NPRM, and would also render a indisputable benefit/cost 
ratio. Upon further review, RSPA agrees that a tank car constructed 
from AAR TC-128, normalized, would provide a level of puncture 
resistance equivalent to a tank car constructed from any steel 
specification proposed in the NPRM. In this final rule, RSPA has 
provided for the use of a DOT 112S200W (non-jacketed tank car) 
constructed from AAR TC-128 normalized steel as an authorized 
packaging, as suggested by the commenter.

L. Implementation of New Requirements

    In the NPRM, RSPA proposed two implementation dates. Under ``Option 
A,'' most of the compliance dates were set at 10 years from the 
effective date of this final rule. This is a period that also coincides 
with the duration frequently specified in typical full-term tank car 
leases, whether a true lease or a financing vehicle; and with the 
``thorough inspection'' interval for tank cars in Interchange Rule 
88.B.2.18 Under ``Option B,'' RSPA proposed that certain tank car 
types and car/commodity combinations be considered for shorter retrofit 
periods, with 5 years given to bring existing cars into compliance. For 
instance, aluminum and nickel tank cars are more vulnerable to 
puncture, and tanks used for transporting PIH materials present special 
hazards.

    \18\Field Manual of the Interchange Rules, adopted by the 
Association of American Railroads, Mechanical Division, Washington, 
D.C., 1992. At intervals not to exceed 10 years, major components of 
the car must be inspected, including body bolsters and center 
plates, center sills, crossbearers, crossties, draft systems and 
components, end sills, side sills, and trucks.
---------------------------------------------------------------------------

    Option A was supported by commenters. Although urging RSPA to adopt 
the 10-year time limit, RPI stated that, because of start-up 
complexities, it will not be reasonable to accomplish this on a 10-
percent per year basis. Instead, RPI suggested that its members were 
willing to modify 50 percent of the fleet in the first 5 years and 50 
percent in the second 5 years. This accomplishes the desired goal while 
minimizing scheduling problems and maximizing efficiency.
    Option B was supported by NTSB who stated that RSPA should require 
tank-head protection, within 5 years, for all class DOT 105 tank cars 
having capacities of less than 70 kl (18,500 gallons) when used to 
transport a Division 2.1 material (flammable gas).
    Most commenters supported the 10-year modification program for 
existing tank cars. RSPA believes, however, that a 5-year modification 
program is more appropriate for class DOT 105 tank cars that have a 
capacity less than 70 kl (18,500 gallons) when used to transport a 
Division 2.1 material. Mandating an accelerated modification program 
for these particular tank cars will ensure that those cars presenting 
the greatest risk are modified first. Therefore, this final rule 
requires that each tank car built on or after the effective date of 
this final rule conform to this final rule. For tank cars built prior 
to the effective date, the phase-in period is 10 years: at least 50 
percent of the fleet in the first 5 years and the balance in the second 
5 years. The phase-in-period for tank cars transporting a Division 2.1 
material is 5 years, with at least 50 percent within 2\1/2\ years and 
the balance in the second 2\1/2\ years. For existing tank cars 
constructed with an internal self-energized manway located below the 
liquid level of the lading, the compliance date is the effective date 
of this final rule.

III. Docket HM-201--Detection and Repair of Cracks, Pits, Corrosion, 
Lining Flaws and Other Defects of Tank Car Tanks

A. Background

    On September 16, 1993, RSPA published in the Federal Register a 
NPRM under Docket HM-201; Notice No. 93-15 [58 FR 48485]. The NPRM 
contained proposals to: (1) require the development and implementation 
of a quality assurance program (QAP) at each facility that builds, 
repairs, or ensures the structural integrity of tank 

[[Page 49059]]
cars; (2) require the use of non-destructive testing (NDT) techniques 
in lieu of the current periodic hydrostatic pressure tests for fusion 
welded tank cars to more adequately detect cracks in principal 
structure elements (PSE), the failure of which could cause catastrophic 
failure of the tank; (3) require thickness measurements of tank cars; 
(4) allow for the continued use of tank cars with limited reduced shell 
thicknesses; (5) increase the inspection and test intervals for tank 
cars; and (6) clarify the tank car pretrip inspection requirements. 
Readers are referred to the NPRM preamble for a complete background, 
including a more extensive discussion of issues and citations to 
research data summarized in the final rule.
    RSPA received 31 comments in response to the NPRM from members of 
the various industries that own, lease, transport, or use tank cars. 
RSPA and FRA have given full consideration to all comments in the 
development of this final rule. Following is a summary of the written 
comments, a summary of the final rule, and the actions taken by RSPA 
and FRA in this final rule:

B. Damage-Tolerance Fatigue Evaluations

    In 1992, the NTSB issued a report on the inspection and testing of 
tank cars. The report disclosed that many tank car defects are not 
routinely detected. These defects may suddenly grow to a critical size 
resulting in failure of the tank car. The NTSB recommended that FRA and 
RSPA develop requirements for the periodic inspection and tests of tank 
cars to help ensure the detection of cracks before the cracks propagate 
to a critical length. Such requirements would establish inspection and 
test intervals based on the defect size detectable by the inspection 
and test method used and on the stress level and crack propagation 
characteristics of the PSE based on a ``damage-tolerance'' approach. 
The Federal Aviation Administration (FAA) defines a structure as damage 
tolerant if the structure has been evaluated to ensure that, should 
serious fatigue, corrosion, or accidental damage occur within the 
operational life of the structure, the remaining structure can 
withstand reasonable loads without failure or excessive structural 
deformation until the damage is detected (FAA Advisory Circular AC No. 
25.571-1A). Damage-tolerance assumes that flaws exist in the structure 
and that the design of the structure is such that these flaws will not 
grow to a critical size and cause catastrophic failure to the structure 
within a specified damage detection period. The damage detection period 
depends on the characteristics of each PSE, each element's 
susceptibility to severe corrosive environments, the inspectability of 
each element, the inspection method, and procedures used and 
maintenance practices.
    In the NPRM, RSPA proposed to allow tank car owners to use an 
alternative inspection and test procedure or interval based on the 
completion of a damage-tolerance fatigue evaluation. The evaluation 
procedures would be reviewed by the AAR and approved by the Associate 
Administrator for Safety, FRA. As stated in the NPRM, FRA believes that 
some tank car owners may be able to reduce inspection and test costs by 
using damage-tolerance fatigue evaluation procedures that incorporate: 
(1) In-service inspection and test using techniques such as ultrasonic 
or acoustic emission; (2) sampling of individual designs with a 100 
percent inspection and test of the design if a crack is found; (3) 
inspection and test intervals unique to each tank car component; and, 
(4) inspection and test intervals based on the degree of risk a 
material poses (i.e., high risk materials have shorter inspection and 
test intervals than those with low risks).
    Most commenters stated that the damage-tolerance approach is a 
significant step toward advancing the detectability of defects and well 
suited to a tank car and its associated structure. They suggested that 
RSPA and FRA expand the damage-tolerance approach, for fatigue, to 
include other types of damage mechanisms, such as corrosion, corrosion 
fatigue, original fabrication defects, stress corrosion cracking, 
impact damage, and damage caused by an accident.
    RSPA and FRA agree that the use of a damage-tolerance approach to 
periodic inspection and test of tank cars would substantially increase 
the likelihood of the detection of cracks and crack-like defects before 
such defects propagate to a critical size. RSPA and FRA also believe 
that the inspection interval for each PSE should be based on the 
inspection method used, the stress level in each PSE, and the crack 
propagation characteristics of each PSE.
    The agencies realize, however, that in order to fully implement a 
damage-tolerance program, it will take years for each owner or 
manufacturer of a tank car to analyze each element on the tank car, and 
to support the results of such analysis with test evidence and service 
experience. FRA is currently working with the AAR Tank Car Committee, 
the RPI, tank car owners, lessors, and manufacturers to develop 
acceptable non-destructive testing techniques, and to develop an 
inspection and test program based on damage-tolerance principles. These 
programs include finite element analysis of the stub sill and its 
attachment to the tank shell to identify the PSE on the tank car that 
should be examined, over-the-road tests to define the typical 
environmental loading spectrum expected in service, and a damage-
tolerance evaluation of the structure.
    In this final rule, RSPA is revising the regulatory text for the 
damage-tolerance fatigue evaluation proposed in Sec. 180.509(k). This 
revised requirement provides that an acceptable damage-tolerance and 
fatigue evaluation include other types of damage mechanisms and is 
supported by test evidence and, if available, by service experience.

C. Inspection and Test Intervals

    FRA found that cracks may reach a critical size in a PSE within 
about 400,000 miles of railroad service [see ``Owners of Railroad Tank 
Cars; Emergency Order Requiring Inspection and Repair of Stub Sill Tank 
Cars,'' (Emergency Order Number 17) 57 FR 41799, September 11, 1992]. 
To ensure against premature failure, common procedures for NDT allow 
for two opportunities to inspect an item before predicted failure. 
Because tank cars travel an average of about 18,000 miles per year and 
most cracks become critical at about 400,000 miles of railroad service, 
in the NPRM, RSPA proposed an inspection and test interval, based on a 
simplified damage-tolerance evaluation, of 10 years to allow for two 
opportunities to inspect an item before predicted failure.
    For the sake of efficiency, and to increase safety margins for most 
cars, RSPA proposed to implement the 10-year inspection and test 
interval starting at what would otherwise be the next scheduled tank 
hydrostatic pressure test. For tank cars within a 20-year test cycle, 
RSPA proposed that the next inspection and test date be the publication 
date of this rule plus one half of the remaining years to what would 
otherwise be the next scheduled tank hydrostatic test. After that the 
tank would require an inspection and test on a 10-year interval.
    For materials corrosive to the tank and shipped in non-lined or 
non-coated tank cars, RSPA proposed an inspection and test interval 
based on the lower of (1) the corrosion rate of the material on the 
tank shell or (2) the fatigue life of the tank structure as discussed 
above. RSPA and FRA developed a test interval to ensure that the 
calculated thickness of the tank at the next inspection and 

[[Page 49060]]
test will not fall below the proposed allowable minimum wall thickness. 
The inspection and test interval in this case is calculated by 
subtracting the actual thickness (measured at the time of construction 
or any subsequent inspection and test) from the allowable minimum 
thickness and then dividing that difference by the corrosion rate of 
the hazardous material on the tank. Consequently, as the shell 
thickness corrodes throughout the service-life of the tank, the tank 
must receive an inspection and test more frequently.
    Commenters supported the proposed inspection and test program for 
most tank cars. They suggested, however, that RSPA consider the 
availability of tank car facility space and the practicality of 
implementing the new inspection and test and quality assurance programs 
without immobilizing a large number of tank cars. In particular, 
commenters suggested that RSPA not reduce the inspection and test 
intervals for tank cars constructed during the 1975-1979 period that 
are now subject to a 20-year hydrostatic pressure test interval. As 
proposed, these particular tank cars become due for inspection and test 
during the years 1995 through 1997. A major oil company stated that 
these particular tank cars represent at least 20 percent of its tank 
car fleet.
    Several commenters stated tank cars used to transport chlorine, 
unlike other tank cars, are currently tested every two years. As such, 
all 8,000 tank cars in chlorine service would have to be brought in 
conformance with the new inspection and test requirements within two 
years. One company stated that it maintains 3,000 tank cars in chlorine 
service and it would have to inspect 5.7 tank cars per day, which may 
not be feasible because companies must first determine efficient 
inspection techniques and provide training to inspection personnel. 
Commenters further argue that because tank cars that transport chlorine 
have an insulation system and a metal jacket, the inspectability of 
certain PSE on these tank cars is difficult; accordingly, RSPA should 
not mandate the new requirements in the short-term until the industry 
and the government specify the acceptable NDT techniques for inspecting 
tank cars that have metal jackets.
    The RPI suggested that RSPA phase in the new procedures slowly by 
beginning with tank cars without a metal jacket and then tank cars 
having a metal jacket when appropriate inspection techniques are 
developed. Although RPI did not explain the basis for its comment, RSPA 
and FRA assume that the reason behind RPI's comment is the difficulty 
of inspecting PSE on a tank car having an insulation system covered by 
a metal jacket or a thermal protection system; consequently, tank car 
facilities will need time to develop the inspection methods and to 
train inspection personnel on the use of those methods. Only after 
identifying the appropriate inspection method and by training 
inspection personnel, will there be a high probability of defect 
detection.
    Several commenters requested that RSPA not require, in proposed 
Sec. 180.509(b)(3), an inspection and test [requalification] of the 
tank each time it is transferred into or out of a service that is 
corrosive to the tank, which one commenter stated could occur 4 times 
per month. Another commenter stated that the program is redundant with 
proposed Sec. 180.509(c)(3)(ii) and, therefore, the section should be 
deleted. The Chemical Manufacturers Association (CMA) suggested that 
RSPA amend the proposal to allow for routine transfers, so long as the 
tank car is within the established intervals for the periodic 
inspection requirements. A commenter suggested that localized 
modifications to a tank, such as modifying nozzles or bottom outlets, 
should not subject the tank to a complete requalification.
    Based on the comments received, RSPA is not adopting proposed 
paragraphs (b) (3) and (4). Paragraphs (b) (5) and (6) are renumbered 
accordingly.
    RSPA and FRA also agree that local repairs or modifications should 
not subject the tank to the full inspection and test program, because 
the repair or modification must be done according to Appendix R of 
AAR's Specifications for Tank Cars. Appendix R specifies the procedures 
for repairs, alterations, and conversions of tank cars and the 
appropriate non-destructive testing method to ensure that the repairs, 
alterations, or conversions were performed correctly.
    RSPA and FRA agree that the new inspection and test methods, 
combined with other FRA mandated inspection programs, may cause a 
tremendous backlog of tank cars awaiting inspection. Therefore, to 
maintain an acceptable level of safety, but also to allow for an 
orderly and acceptable phased-in NDT inspection and test program, RSPA 
will delay the compliance date of this final rule for 24 months for 
tank cars without metal jackets and 48 months for tank cars having a 
metal jacket or a thermal protection system. Before the compliance 
date, tank cars may be given an inspection and hydrostatic test in 
accordance with the current requirements or the requirements contained 
in this final rule. After the compliance date, each tank car must be 
given an inspection and test according to the requirements contained in 
this final rule on or before the next scheduled tank hydrostatic 
pressure test date.

D. High-Mileage Tank Cars

    FRA realizes that some tank cars can travel in excess of 18,000 
miles each year and, by doing so, the tank cars may reach 200,000 miles 
of railroad service before their first periodic inspection and 400,000 
miles before their second.
    The NTSB expressed its concerns that the proposed regulations 
recommend, but do not require, more frequent inspections and tests for 
tank cars with mileage rates that exceed the average. Further, because 
there is no requirement to maintain cumulative mileage on individual 
tank cars, the NTSB expressed concern that high-mileage tank cars would 
not be identified for the more frequent inspections and tests, thereby 
increasing the possibility of a non-detected fatigue crack propagating 
and causing a structural failure within the 10-year inspection and test 
cycle.
    RSPA and FRA agree with the NTSB that high-mileage tank cars should 
receive an inspection and test prior to reaching 200,000 miles of 
railroad service. However, no requirement for the maintenance or 
retention of car mileage records was proposed. Because car owners keep 
records of car mileage, the owners can ensure that tank cars having 
high-mileage are inspected more frequently than the inspection and test 
intervals adopted in this final rule. Current Sec. 173.24(b) provides 
that each package used for the shipment of hazardous materials shall be 
so designed, constructed, and maintained . . . so that under conditions 
normally incident to transportation--the effectiveness of the package 
will not be substantially reduced. Thus, an owner has an obligation to 
ensure the continuing effectiveness of a tank car. This duty is not 
unlike that of an owner of an automobile who replaces the tires on his 
or her car when worn and not based on the warranty period. FRA will, 
during its inspection activities, assess the need for a rulemaking (1) 
to require owners to retain car mileage records and (2) to inspect 
their tank cars before the cars accumulate more than 200,000 miles of 
railroad service.

E. NDT Techniques

    In the NPRM, RSPA proposed to require that the bottom shell of 
fusion welded tank cars be inspected periodically by appropriate NDT 
techniques, such as optically aided visual inspections, ultrasonic, 

[[Page 49061]]
radiographic, magnetic particle, and dye penetrant testing methods, in 
lieu of hydrostatic pressure tests.
    All commenters supported the use of NDT techniques to assess the 
integrity of a tank car in lieu of a hydrostatic pressure test. Several 
commenters stated that the use of qualification procedures will require 
formal NDT techniques in defined areas where no previous requirements 
existed and will improve the overall safety of tank cars.
    Several commenters suggested that RSPA should authorize the use of 
acoustic emission testing to qualify tank cars for further use. One 
commenter stated that acoustic emission testing is widely used in the 
chemical process industry to assure the integrity of pressure vessels, 
tanks, and piping. The commenter further stated that the overall 
reliability of a series of local tests (ultrasonic, dye penetrant, 
radiography, etc.) is incorrectly compared with the reliability of a 
single global test (hydrostatic, acoustic emission) and that 
substitution of multiple local tests for a single global test may 
endanger, rather than enhance the safe transportation of hazardous 
materials.
    RSPA and FRA do not agree with the commenters's conclusion about 
the potential danger of multiple local tests as compared with a single 
global test. RSPA and FRA believe that multiple local tests, focusing 
on known areas of tank car stress, have a safety advantage over single 
global tests, at least with the current state of development of 
acoustic emission testing in the tank car industry. The NDT methods 
mandated by this rule are a safety improvement. As noted immediately 
below, the agencies have underscored their belief in the potential 
benefits acoustic emission testing offers by granting an exemption that 
will permit its development and refinement in a railroad industry 
context.
    Outside the scope of this rulemaking, but related to it by means of 
subject matter, Monsanto Chemical Company applied for a DOT exemption 
to use acoustic emission technology, in lieu of the current hydrostatic 
retest, for the tank cars it owns. The procedures developed by Monsanto 
to support its exemption were recently evaluated under a research 
contract administered by the government of Canada. (McBride, S. L., 
Acoustic Emission Tank Car Test Method Review & Evaluation, Transport 
Canada Report No. TP 12140E (1994) Montreal, Quebec). The results of 
that research show that Monsanto's acoustic emission testing procedures 
appear to be sound. The report suggests, however, minor refinements in 
the acoustic emission procedures. Taking this into account, RSPA issued 
Monsanto an exemption on September 9, 1994 (DOT-E 10589). The following 
companies were granted ``party to'' status on the Monsanto exemption: 
Union Tank Car Company, Testing Associates, and Physical Acoustics 
Corporation.
    This final rule does not include acoustic emission testing as an 
authorized NDT technique. RSPA and FRA are committed, however, to 
explore new technologies for inspecting and testing tank cars and will 
continue to evaluate the possibly of authorizing the acoustic emission 
testing procedure in the future. In support of this commitment, FRA 
issued a research contract to further explore and refine the use of 
acoustic emission testing procedure and other NDT techniques in 
determining the integrity of insulation and lining covered welds of 
tank cars.

F. Leakage Test

    In the NPRM, RSPA proposed a leakage test that would include all 
product piping with all valves and accessories in place and operative, 
except that during the test the tank car facility would remove or 
render inoperative any venting devices set to discharge at less than 
the test pressure. As proposed, the test pressure would be maintained 
for at least 5 minutes at a pressure of not less than 50 percent of the 
tank test pressure.
    Most commenters opposed the proposed change to use 50 percent of 
the tank test pressure as the standard, because these pressures, some 
as high as 300 psig, would constitute an unsafe maintenance practice. 
RSPA proposed the leak test to ensure that when valves, fittings, and 
manway cover plates are replaced on a tank car after an inspection and 
test, that valves and fittings are securely applied and in a ``leak-
free'' condition under normal operating pressures. This will help 
ensure against product leakage from a valve, fitting, or manway cover 
plate should the vapor pressure of the commodity rise after the shipper 
loads the tank car, normally on its first trip after an inspection and 
test at a tank car facility.
    Berwind Railway Service Company suggested conducting the leak test 
at 30 psig for tank cars having a test pressure less than or equal to 
200 psig and 50 psig for tank cars having a tank test pressure greater 
than 200 psig. AAR and RPI supported similar pressures. In the 
commenters experience, pressures of this magnitude are effective in 
ensuring that tank cars are released from tank car facilities in a leak 
free condition.
    The suggested leak test pressures are similar to the leak test 
pressures currently used to qualify highway cargo tanks. For example, 
the leak test for a cargo tank may not be less than 80 percent of the 
tank design pressure (or its maximum allowable working pressure 
[MAWP]); or, the maximum normal operating pressure when the cargo tank 
has a MAWP equal to or greater than 6.9 Bar (100 psig); or, 4.1 Bar (60 
psig) when the cargo tank is used to transport liquefied petroleum gas. 
After considering the comments, RSPA and FRA agree that a lower leak 
test pressure would provide an adequate leak test with less risk to 
persons performing the test. In this final rule, RSPA is requiring a 
leak test at 30 psig for tank cars having a test pressure less than or 
equal to 200 psig and a leak test at 50 psig for tank cars having a 
tank test pressure greater than 200 psig.

G. Bottom Shell

    FRA has found that principal structural elements (PSE) located 
within four feet of the bottom longitudinal centerline are susceptible 
to fatigue cracking due to repeated loading conditions. Stress 
concentrations in these areas may cause the formation of small cracks 
that may not be detected under the current inspection and test 
procedures. Because some defects may lie outside the area currently 
defined as the bottom shell, such as those in the attachment welds of 
bottom discontinuities, RSPA proposed, based on FRA's findings, to 
revise the current definition of the bottom shell by enlarging the area 
from 60.96 cm (two feet) to 121.92 cm (four feet) on each side of the 
bottom longitudinal center line of the tank.
    The Chlorine Institute, CMA, and others agreed that experience has 
shown that the bottom shell is prone to fatigue cracking. However, all 
known fatigue-related defects have originated within two feet of the 
bottom longitudinal centerline of the tank, which is the area most 
highly stressed in train operation.
    RPI's comments referenced a report, ``Final Phase 14 Report on the 
Stub Sill Buckling Study,'' that shows, when stub sill tank cars are 
subjected to static and dynamic (impact) loads, a complex biaxial 
stress field results in the shell area between the stub sills. The 
report shows that measured strains are due to a combination of axial 
compression and bending components and at high loads, high magnitude 
strains occur over certain localized areas. The results of the RPI 
report show that the stresses on the bottom longitudinal centerline of 
the tank are about 1.8 times the magnitude of the stresses occurring 
from two to 

[[Page 49062]]
four feet from the bottom longitudinal centerline.
    RPI further stated that fatigue damage increases exponentially with 
the ratio of stress ranges and that crack initiation and propagation 
within the area of two feet from the bottom longitudinal centerline is 
much faster than the area two to four feet from the bottom longitudinal 
centerline. Based on the Phase 14 report, RPI suggests that the bottom 
shell definition should encompass an area that lies below the 
horizontal plane of two longitudinal parallel lines extending two feet 
on each side from the bottom longitudinal centerline, through the tank 
heads. K & K Consultants, Incorporated, who also commented on the Phase 
14 report provided a summary of the data and explained that the 
principal stresses in the tank are approximately parallel to the bottom 
longitudinal centerline, and that the stresses tend to decrease 
circumferentially away from the bottom longitudinal centerline.
    After consideration of the comments, RSPA and FRA agree that four 
feet on each side of the bottom longitudinal centerline is overly 
restrictive. Therefore, the current definition of bottom shell in 
Sec. 171.8 is retained.

H. Structural Integrity Inspections

    In the NPRM, RSPA proposed a structural integrity inspection and 
test on all circumferential and longitudinal welds and welded 
attachments on the bottom of the tank, within 121.92 cm (4 feet) on 
each side of the bottom tank centerline, using one or more non-
destructive test methods. As explained above under the heading ``bottom 
shell,'' several commenters stated that this area is more appropriately 
defined as within 60.96 cm (2 feet) on each side of the bottom tank 
centerline.
    FRA has learned that some high-stressed areas lie outside of the 
60.96 cm (2 feet) bottom longitudinal centerline area. Brake pipe 
supports, body stiffeners, tank anchors, and other attachments and 
structures having large welds are examples of high-stressed areas that 
may lie outside of this area. As a general matter, the HMR require 
reinforcing pads for these high-stressed areas between external 
brackets and tank shells if an attachment weld exceeds 6 linear inches 
of 0.64 cm (0.25 inch) fillet weld per bracket or bracket leg 
(Secs. 179.100-16 and 179.200-19). In its Tank Car Manual, AAR requires 
the use of a reinforcing pad if a bracket or attachment welded directly 
to the tank could cause damage to the tank, either through fatigue, 
over-stressing, denting, or puncturing in the event of an accident. If 
a reinforcing pad is used under a bracket or attachment, AAR specifies 
that the pad shall not be less than 0.64 cm (0.25 inch) thick. For 
further information, see sections E15.01 and E15.02 of AAR Tank Car 
Manual.
    Further, in an investigation of tank shell cracking, FRA found that 
local areas of the tank shell near tank discontinuities are subjected 
to the combination of live-load stress in addition to the residual 
stress induced by reinforcement pad welds, and that this combination 
makes the sensitivity of the welded area near the discontinuity and 
reinforcing pad weld susceptible to fatigue crack propagation. After 
performing residual stress measurements of retro-fitted tank car 
weldments, AAR confirmed FRA's findings that significant tensile 
stresses (on the order of 30,000 psi) occur in the vicinity of the 
fillet welds having a throat size (weld depth) greater than 0.64 cm 
(0.25 inch). In general, fillet welds larger than 0.635 cm (0.25 inch) 
are considered structural welds, and AAR requires post weld heat 
treatment when these welds, such as interior brackets, supports, and 
reinforcement bar pads, have a throat thickness exceeding 0.635 cm 
(0.25 inch). For further information see R17.01 of AAR Tank Car Manual.
    In its comments to the NPRM, the Sulphur Institute stated that 
stress type defects may originate in some attachment fillet welds, such 
as those greater than 0.64 cm (0.25 inch) that are currently located 
outside of the current bottom shell definition. Examples given were 
body stiffener and brake pipe support fillet welds.
    RPI gave similar comments by suggesting that the inspection of 
attachment welds on the bottom of the tank should be limited to 
structure welds, such as transverse fillet welds larger than 0.64 cm 
(0.25 inch), the terminations of longitudinal fillet welds larger than 
0.64 cm (0.25 inch), and tank shell butt welds within 60.96 cm (24 
inches) of the bottom longitudinal center line and between the body 
bolsters. When asked to clarify its comments, RPI told FRA that a 0.64 
cm (0.25 inch) fillet weld refers to the leg-length (see also the 
definitions of ``Size [fillet]'' and ``Full Fillet Weld'' in Section 
W2.00 of AAR Tank Car Manual). Furthermore, RPI stated that limiting 
the inspection and test requirements to fillet welds greater than 0.64 
cm (0.25 inch), would exclude non-structural fillet welds, such as 
those used to attach exterior heater coils.
    RSPA and FRA agree that the stress concentration effects around 
structural attachments will cause the formation of fatigue cracks and, 
if these cracks are not detected and repaired during routine 
maintenance of the tank car, such cracks will grow to failure. In this 
final rule, RSPA requires a structural integrity inspection and test in 
those areas known to develop cracks. Such an inspection and test 
includes transverse fillet welds greater than 0.64 cm (0.25 inch) 
within 121.92 cm (48 inches) of the bottom longitudinal center line, 
the termination of longitudinal fillet welds greater than 0.64 cm (0.25 
inch) within 121.92 cm (4 feet) of the bottom longitudinal center line, 
and all tank shell butt welds within 60.96 cm (2 feet) of the bottom 
longitudinal center line. By limiting the required inspection to known 
areas of crack initiation, RSPA and FRA can expect an increase in the 
probability of defect detection, as well as an improvement in the 
reliability of the inspection results and a reduction in inspection 
costs.
    The Sulphur Institute commented that if the integrity of the 
coatings or linings applied to protect tank car tank metal remains 
acceptable, there should be no need to remove the coating or lining to 
inspect the tank for structural integrity. The purpose of the 
structural integrity inspection is to ensure the detection of fatigue 
cracks before the cracks progress to a dangerous size, thereby reducing 
the residual strength of the tank. In order to inspect each PSE to 
confirm structure integrity, tank car facilities may need to remove 
portions of the lining or coating. Owners may choose, however, to use a 
non-destructive testing method that interfaces between different 
materials, with effective penetration, so that there will be no need to 
remove the coating or lining. Such non-destructive testing methods 
include radiography and ultrasonics.

I. Minimum Shell Thickness

    Recognizing that a tank car shell tends to decrease in thickness 
over time, RSPA proposed in the NPRM a definite service-life shell 
thickness requirement for all areas of the tank shell and heads. The 
proposed minimum in-service shell thickness requirement was based, in 
part, on an AAR-RPI report, ``Allowable Thickness Reduction from 
Minimum Prescribed Thickness of Carbon Steel Tank Car Tanks,'' that 
discussed the investigation of shell thickness below the Part 179 
construction standard in certain areas. The RPI-AAR report considered 
the effects of an overall or localized reduction in the tank wall 
thickness from a principal mode of failure--failure of a tank car due 
to the effects of fire, fatigue crack growth leading to fracture, and 
failure of the tank due to puncture of the heads. The results of the 
RPI-AAR report show that 

[[Page 49063]]
the effects of a slightly reduced shell thickness on tank cars used to 
transport ``ethylene oxide,'' ``butadienes, inhibited,'' ``vinyl 
chloride,'' ``propane,'' and ``propylene'' will not have a significant 
effect on safety. The NPRM also proposed to allow localized areas of 
thickness reduction to have a total cumulative surface perimeter not 
exceeding 182.88 cm (72 inches), consistent with the current provisions 
in Sec. 173.31(a)(11)(iv).
    In its comments to the NPRM, RPI suggested that the 72-inch 
cumulative perimeter should apply to the bottom shell only. RPI further 
stated that RSPA should allow the rest of the tank shell, excluding the 
tank heads, to have an unlimited number of two foot perimeter 
reductions, provided such areas of reduction are separated by at least 
16 inches (twice the diameter of a circle having a 24 inch 
circumference).
    AAR also suggested that the permitted local thickness reductions 
for non-pressure tank cars should depend on cause. AAR thickness 
reduction tables, endorsed by many commenters under an earlier 
rulemaking, differentiated between corrosion and mechanical damage for 
non-pressure tank cars (see ``Shippers Use of Tank Cars with Localized 
Reductions in Shell Thickness,'' 54 FR 8336, 8337, February 28, 1989). 
AAR further commented that there is no need to make a distinction 
between the cause of damage for pressure tank cars because of the 
stricter limits imposed on such cars. AAR proposed that, for non-
pressure tank cars, RSPA should permit a 0.48 cm (0.188 inch) local 
thickness reduction in the top shell and 0.32 cm (0.125 inch) local 
thickness reduction in the bottom shell for corrosive damage. For 
mechanical damage, RSPA should permit 0.32 cm (0.125 inch) local 
thickness reduction in the top shell and a 0.16 cm (0.063 inch) local 
thickness reduction in the bottom shell. AAR asserts that the stresses 
from a given thickness reduction attributed to mechanical damage can be 
greater than the same reduction attributed to corrosion damage, because 
mechanical damage causes a more abrupt change in the thickness.
    After full consideration of the merits of these comments, RSPA and 
FRA agree that there should be no overall limit on the amount of 
surface area with localized reduced shell thicknesses, provided such 
limitations apply only to the top shell of the tank and such areas are 
separated by at least 16 inches. Also, RSPA is modifying the thickness 
reduction table, as recommended by AAR, and endorsed by several 
commenters, to differentiate between corrosion and mechanical damage.
    AAR commented that RSPA proposed, in Sec. 180.509(g), maximum 
thickness reductions from the original thickness of the tank and not 
the required thickness of the tank: a thickness specified in a chart 
summarizing specification requirements (e.g., Sec. 179.101-1(a)), or 
the result of a calculation (e.g., Sec. 179.100-6(a)). RSPA disagrees. 
The proposed section in the NPRM states that--

[a] tank car found with a thickness below the required minimum 
thickness after forming for its specification, as stated in Part 179 
of this subchapter, may . . . [emphasis added]

AAR further stated that RSPA should include an explicit provision 
enabling the owner of a tank car to ``downgrade'' [downrate] the car to 
the point where the loss of thickness exceeds the maximum allowed by 
the regulation. As RSPA stated in the NPRM under the preamble heading, 
``Safety System Inspections,''

[n]othing in the regulations would preclude a tank car owner from 
marking a tank as meeting a less stringent specification, such as 
re-marking a specification DOT 112J tank car to a DOT 112S or 
112J400W tank specification to a DOT 112J340W tank specification 
when the tank car no longer conforms to the marked specification.

    Downrating is permissible and a tank car owner may mark a tank as 
meeting a less stringent specification, such as marking a specification 
112A340W tank car to a DOT 111A100W1 tank car when the tank, because of 
its shell thickness, no longer conforms to the marked specification. 
Owners are reminded that changing the marked specification also changes 
the certificate of construction and, when so doing, they must follow 
the procedures in Appendix R of AAR's Specifications for Tank Cars (see 
Sec. 173.31(a)(4) and (f), and Sec. 179.6).
    In its comments, RPI proposed a standardized minimum inspection 
pattern for conducting thickness tests. RPI suggests that thickness 
readings should be taken at the bottom, one side (90 deg.), and the top 
within 6-inches of each circumferential weld for each plate. RPI 
further states that corresponding readings should also be taken along 
the head circumferential weld seam and another reading at the center of 
the tank head. This would result in 32 thickness readings for a four-
ring tank. In addition to the tank shell, two readings would be taken 
on the manway nozzle, the top unloading nozzle, and the sump. According 
to RPI, if an inspector finds corrosion or other damage that reduces 
the shell thickness, additional readings must be taken to more 
specifically identify the damaged area.
    RSPA is not incorporating a written procedure for conducting 
thickness measurements throughout the tank shell to increase the 
probability of defect or corrosion detection. RSPA and FRA believe that 
such procedures belong in the tank car owner's written maintenance 
plans or AAR Specifications for Tank Cars. Throughout this rulemaking, 
RSPA and FRA have developed a course of action that outlines where and 
what to inspect, but not how to inspect. This approach allows each tank 
car owner the flexibility to develop inspection and test procedures 
appropriate for each unique tank car, or a series of unique tank cars 
based on operating and maintenance experience.

J. Lining and Coating Inspections and Tests

    In the NPRM, RSPA proposed an inspection and test requirement for 
tank cars with linings and coatings. This would ensure that the lining 
or coating is in proper condition for the transportation of hazardous 
materials. As proposed, owners of lined or coated tank cars must 
determine the periodic inspection interval and inspection technique for 
the lining and coating, based on the owner's knowledge of the material 
used. The owner would also maintain all supporting documentation used 
to make such a determination, such as the lining or coating 
manufacturer's recommended inspection interval and inspection 
technique, at the owner's principle place of business. Further, the 
supporting documentation used to make such inspection interval 
determinations and the inspection technique would have to be made 
available to FRA upon request.
    All commenters supported RSPA's proposed inspection and test 
requirement for tank cars with linings and coatings. RPI suggested that 
RSPA should specify ``owners of linings and coatings,'' as opposed to 
the ``tank car owner,'' to determine the inspection and test technique 
and interval--since most shippers own the tank car lining or coating as 
opposed to the tank car owner. Mobil Oil Corporation and others 
suggested that the regulation should only apply to linings and coatings 
installed to protect the tank shell, as opposed to those applied for 
lading integrity or quality.
    RSPA and FRA agree with RPI and are revising the proposed 
requirements to incorporate RPI's suggestions. In this final rule, 
owners of linings and coatings in tank cars must determine the 

[[Page 49064]]
periodic inspection interval and inspection technique for the lining 
and coating, based on the owner's knowledge of the material used. This 
will ensure that the lining or coating is in proper condition for the 
transportation of hazardous materials. The owner must also maintain all 
supporting documentation used to make such a determination, such as the 
lining or coating manufacturer's recommended inspection interval and 
inspection technique, at the owner's principle place of business. The 
supporting documentation used to make such inspection interval 
determinations and the inspection technique must be made available to 
FRA upon request.
    Further, in Sec. 180.509, RSPA is revising paragraphs (c)(3)(i) and 
(iii)(A) to require an inspection and test of the lining or coating 
only when the lining or coating is applied to protect the tank shell 
from a lading such as hydrochloric acid.

K. Safety System Inspections

    In the NPRM, RSPA proposed to add explicit requirements for the 
inspection of thermal protection systems, tank head puncture resistance 
systems, coupler vertical restraint systems, and devices used to 
protect discontinuities. If, after an inspection, one or more of these 
systems do not conform to the applicable specification requirements 
contained in Part 179, renewal or repair of the system is necessary to 
continue the qualification of the tank car. RSPA received two comments 
on this proposal, both indicating support.
    In this final rule, RSPA is adopting the requirements for the 
inspection of these safety systems.

L. Quality Assurance Program (QAP)

    In the NPRM, RSPA proposed to require that each tank car facility 
establish a Quality Assurance Program (QAP) to detect non-conformities 
during the manufacturing, repair, or inspection and test process. A 
tank car facility means an entity that manufactures, repairs, inspects, 
or tests tank cars to ensure that the tank cars conform to Parts 179 
and 180, that alters the certificate of construction of the tank car, 
or that verifies that the tank car conforms to the specification.
    All commenters endorsed the QAP proposal; however, several 
commenters suggested that RSPA delay the effective date for at least 18 
months so that tank car repair facilities will have the opportunity to 
develop a QAP. In its comments, AAR supported RSPA's QAP requirements 
and further stated that the QAP developed by RSPA is consistent with 
AAR's quality assurance requirements.
    Several commenters asked RSPA to clarify whether or not a tank car 
facility includes a shipper's loading facility where items such as 
gaskets and manway bolts are normally inspected and replaced as part of 
a ``pre-trip'' inspection. It is not the intention of RSPA to include 
within the definition of a tank car facility a shipper's facility where 
pre-trip inspections are performed. Generally, a tank car facility 
evaluates the tank structure to ensure that, if serious fatigue, 
corrosion, or accidental damage occurs within the inspection and test 
interval, the remaining structure can withstand reasonable loads 
without failure or excessive structural deformation. A shipper, on the 
other hand, ensures by inspection that the tank is in proper condition 
for transportation from point of origin to destination.
    Based on the comments received, RSPA is requiring each tank car 
repair facility to develop a QAP that has the means to detect any 
nonconformity in the manufacturing, maintenance, or repair process and 
that has the means to prevent its recurrence. Furthermore, the QAP must 
ensure that the finished product conforms to the requirements of the 
applicable specification and the regulations in the HMR. RSPA is also 
clarifying the definition of a tank car facility to mean an entity that 
manufactures, repairs, inspects, or tests tank cars to ensure that the 
tank cars conform to Parts 179 and 180, that alters the certificate of 
construction of the tank car, that ensures the continuing qualification 
of a tank car by performing a function prescribed in Parts 179 or 180, 
or that makes any representation indicating compliance with one or more 
of the requirements of Parts 179 or 180. This language mirrors that for 
the qualification of highway cargo tanks (see Sec. 180.2). A shipper 
that inspects a tank car solely to ensure that the tank car is safe for 
transportation is not performing a periodic qualification function. On 
the other hand, a shipper who continues the qualification of a tank 
car, by performing a function described in Parts 179 or 180, meets the 
definition of a tank car facility.

M. Inspection Requirements Prior to Transportation

    The current regulations, at Sec. 173.31(b)(3), require that the 
shipper inspect a tank car before releasing it into transportation to 
ensure that, among other things, the closures are in a ``tool-tight,'' 
secure condition. Further, closures on the tank (under 
Sec. 173.24(f)(1)(ii)) must be so designed and closed that ``under 
conditions (including the effects of temperature and vibration) 
normally incident to transportation . . . the closure is secure and 
leakproof.''
    RSPA and FRA proposed in Sec. 174.68 that tank cars be inspected 
prior to transportation as an amendment to the current requirements 
because of their concerns about tank cars in transportation with loose 
closures. Since 1989, FRA inspectors have found loose closures on tank 
cars containing hazardous materials more than 23,000 times. In that 
same period, RSPA has received about 1,100 to 1,200 incident reports 
each year on tank cars that had released product, often as a result of 
a loose closure. Those releases resulted in injury to 85 railroad 
employees. This history shows that more needs to be done to ensure that 
tank cars conform to the regulations when offered for transportation. 
It is FRA's experience that properly designed and secured closures 
(closures meeting the standards of Secs. 173.24 and 173.31) do not 
become loose during transportation and that most of the incidents 
reported to RSPA reflect poor pre-trip preparation of the tank car 
prior to offering it for transportation. In order to clearly state the 
offerors responsibility for pre-trip inspection of a tank car, 
Sec. 174.68 in the NPRM proposed a rebuttable presumption against a 
proper pre-trip inspection if unsecured closures were found in transit.
    RSPA and FRA believe that aligning the inspection requirements in 
current Sec. 173.31(b) with the design and operations requirements in 
Sec. 173.24 will clarify their full intent, foster compliance with 
safety standards, and improve hazardous materials transportation 
safety. Comments on the proposed Sec. 174.68 came from most of those 
filing responses to the NPRM and they covered five aspects of the 
proposal. First, several commenters argued that Sec. 174.68 was the 
wrong place for pre-trip inspection requirements, that, as shipper 
responsibilities, they belonged in Part 173. RSPA and FRA agree and the 
final rule includes pre-trip inspection in Sec. 173.31.
    Second, several commenters said that the proposal raised the duty 
of care for pre-trip car preparation to an all but impossible level. 
Current Sec. 173.31(b)(1) requires that ``the shipper must determine to 
the extent practicable, that . . . fittings are in proper condition. . 
. .'' [emphasis added] The origin of the phrase ``to the extent 
practicable'' in Sec. 173.31(b) has its roots in the Interstate 
Commerce Commission's (ICC) regulations prior to 1960. In those 

[[Page 49065]]
regulations, the ICC required shippers, before loading the tank car, to 
examine the tank and each appurtenance to see that the safety and 
outlet valves, safety vents, the excess flow valves (if any), the 
closures of all openings, and the protective covers of all 
appurtenances were in proper condition.
    In a letter dated July 10, 1959, to AAR, the Manufacturing 
Chemists' Association (MCA) stated that the addition of the words ``to 
the extent practicable'' in the tank car loading section was to clarify 
the purpose of the regulations and to make the regulation more 
realistic and to eliminate from the regulation items which were either 
very difficult to inspect or very expensive to inspect such as a full 
inspection of safety relief valves or excess flow valves. Read 
literally, the regulation at that time would impose a duty on the 
shipper to disassemble and inspect safety valves and excess flow valves 
prior to each trip.
    As a result of the MCA letter in 1959, AAR petitioned the ICC to 
amend the current regulations by inserting the phrase ``to the extent 
practicable'' in the tank car loading section. The ICC agreed and the 
new phrase went into the regulations on March 23, 1960, under Order 
Number 42. From the beginning, this phrase was meant to reflect the 
practical impossibility of, for instance, taking the valves apart 
before each trip; the additional language was not intended to excuse 
poor pre-trip preparation. This final rule does not enlarge the ``to 
the extent practicable'' standard.
    Third, several commenters seemed to confuse the essential elements 
of the loose closure violation by arguing that evidence of a leak (or 
release of product) in transit does not necessarily prove the lack of a 
pre-trip inspection. They mistakenly believed that the proposal focused 
on releases of hazardous materials rather than the broader fault: loose 
fittings and closures. FRA and RSPA agree that leaks can develop in 
transit from sources other that insecure closures, the failure of a 
rubber lining and the failure of a frangible disc are two possible 
examples. This provision was developed from the requirement in the 
current Sec. 173.31(b) that closures must be secured in place with an 
appropriate tool, and the final rule makes no changes in that 
requirement.
    Fourth, many commenters argued that the condition of tank cars in 
transit is the responsibility of the railroads, that it is their duty 
to ensure that the closures are, and remain, tight. RSPA and FRA note 
that current Sec. 173.31(b)(3) requires the shipper to make closures 
``tool tight'' prior to shipping and that Sec. 173.24(b) and (f) 
require closures to be designed, maintained, and closed so that ``under 
conditions (including the effects of temperature and vibration) 
normally incident to transportation'' they will remain secure. 
Responsibility for tight closures must rest primarily with the offeror. 
The railroads' duty to inspect a tank car is aimed at detecting obvious 
leaks and defects in the running gear of the vehicle. FRA's pre-
departure inspection requirements--applicable to all trains whether or 
not carrying hazardous materials--are found at 49 CFR 215.13. Appendix 
D to Part 215 describes the inspection to be performed by a train crew, 
``At each location where a freight car is placed in a train and 
[designated inspectors] are not on duty. . . .'' Appendix D requires 
the train crew to reject a placarded hazardous materials tank car from 
which lading is leaking. As the National Industrial Transportation 
League said in its comments, ``The key issue in determining the 
regulatory responsibilities under the HMR should be to determine which 
functions parties actually performed, or should have performed.'' This 
final rule is not intended to, nor does it, change these essential 
relationships.
    Fifth, several commenters argued that the proposed rebuttable 
presumption will be impossible to meet. The proposed rule states 
examples (derailment and vandalism) that will rebut the presumption, 
but they are not intended to be exclusive. In FRA's experience in 
discussing alleged violations with shippers over the past few years, 
the following circumstances have led to either termination or a penalty 
amount significantly reduced from that originally proposed, depending 
on the facts and circumstances of each case:
     Delivery to a mistaken destination and subsequent 
rerouting to the original destination,
     Erroneous spotting at a repair facility,
     Actual delivery to the consignee prior to inspection,
     Abnormally rough handling by a railroad,
     Gaskets, otherwise secure at the start of the trip, 
deteriorating enroute in a manner the offeror could not have foreseen.
    One commenter cited case law on irrebuttable presumptions. RSPA and 
FRA agree with the commenter that a presumption impossible to rebut 
would not be proper; for the reasons given, RSPA and FRA do not view 
the presumption in the regulation published today as impossible to 
rebut.
    In some cases, FRA has seen pre-trip inspection check lists that 
were at obvious odds with the conditions discovered on the car. The 
rebuttable presumption stated today is not designed to make enforcement 
``easier,'' it is designed to make responsibility more certain. For 
most shippers of hazardous materials, today's rule will not mean a 
change in the regulator/regulated relationship.
    When FRA issues a Notice of Proposed Violation for an alleged 
violation of the HMR, the respondent (railroad, shipper, or 
manufacturer) is afforded the opportunity to investigate the charges 
and to collect factual evidence to mitigate or dismiss the case. 
Respondent has the opportunity for a hearing. FRA, or an Administrative 
Law Judge, considers respondent's submissions, together with the 
factors in 49 U.S.C. Sec. 5123(c), before reaching a decision. The 
standard in this final rule does not change the process by which FRA 
enforces railroad related hazardous materials violations. FRA expects 
that, by clarifying the responsibility of the shipper, there will be 
fewer loose closures on tank cars and fewer injured railroad employees.
    Several commenters mentioned mishandling, even abusive handling, by 
the railroads. FRA's own studies have demonstrated that overspeed 
impacts in railroad switching operations are far from a rarity, but FRA 
is not aware that overspeed impacts will loosen the threaded fasteners 
securing lading retention fittings on a tank car. Overspeed impacts can 
cause severe structural damage, lessen the service life of the car, and 
cause frangible safety vent discs to rupture. In such cases, 
enforcement actions against the railroads are appropriate, and FRA 
pursues them. One shipper, PPG Industries, Inc., put impact recorders 
on a test fleet of 50 tank cars operated out of its Lake Charles, 
Louisiana plant. The impacts in excess of 6G's (about 8 miles per hour) 
between July 1992 and December 1993 are documented in PPG's comments in 
this docket. Because they are limited in geographic scope, RSPA and FRA 
cannot say that this data presents a typical picture, nation-wide, but 
PPG's charts are graphic evidence, arranged by railroad and by 
terminal, that railroad tank cars are subject to stresses well above 
their optimum operating environment.
    In the final rule, RSPA is articulating a rebuttable presumption 
standard aimed specifically at loose closures on tank cars. The 
statement of this presumption in Sec. 173.31(d)(2) does not mean, 
however, that there is a different standard for railroad tank cars than 
for 

[[Page 49066]]
other packagings used to transport hazardous materials. The ``secure 
and leakproof'' standard established in Sec. 173.24(f) applies to 
closures on all packagings used for transportation. If a hazardous 
materials package is discovered with loose closures, either the 
closures were not designed properly or they were not tightened 
properly. Neither RSPA nor FRA are aware of hazardous materials 
packagings designs that allow closures to loosen in transit. Hence the 
presumption that, when an inspector discovers a loose closure, it was 
not tightened properly. RSPA has made the presumption explicit for 
railroad transportation because FRA's enforcement experience, discussed 
earlier, proves the need to focus responsibility on those who prepare 
hazardous materials for transportation.
    The following table lists the adopted paragraphs or sections and, 
where applicable, the corresponding paragraph or section contained in 
the current HMR. In some cases, the cross-references are to provisions 
which are similar to, but not identical with current provisions.

------------------------------------------------------------------------
       New section                          Old section                 
------------------------------------------------------------------------
173.31(a)(2).............  173.31(a)(4) [except 4th and 5th sentence].  
173.31(a)(3).............                                               
173.31(a)(4).............  173.31(a)(7) [1st sentence after ``Effective 
                            July 1, 1991...'' and preceding ``..., as in
                            effect on November 16, 1990''].             
173.31(a)(5)                                                            
173.31(a)(6).............  173.31(a)(3) [1st sentence].                 
                           173.31(a)(3)(i).                             
173.31(b)(1).............  173.31(a)(5) [except last sentence].         
173.31(b)(2).............  173.31(a)(12).                               
                           173.31(a)(15) [1st sentence preceding        
                            ``...nonreclosing pressure relief           
                            devices.''] [2nd preceding ``...provided    
                            that the liquid...''] [3rd sentence         
                            preceding ``...breather holes are not...''].
173.31(b)(3)                                                            
173.31(b)(4)                                                            
173.31(b)(5)               .............................................
173.31(b)(6)                                                            
173.31(c)................  173.31(a)(14) [1st sentence preceding        
                            ``...equal to or greater than...''].        
                           173.31(a)(14)(i) [1st sentence preceding     
                            ``...ullage space or dome of tank.''].      
                           173.31(a)(14)(ii).                           
                           173.31(a)(14)(iii).                          
173.31(d)(1)                                                            
173.31(e)(1).............  173.31(a)(17).                               
173.31(e)(2)                                                            
173.31(f)                                                               
173.314(c), Note 2.......  173.314(c), Note 25.                         
173.314(c), Note 3.......  173.314(c), Note 21.                         
173.314(c), Note 4.......  173.314(c), Note 20.                         
173.314(c), Note 6.......  173.314(c), Note 12 [except 1st and last     
                            sentence].                                  
173.314(c), Note 7.......  173.314(c), Note 18 [1st sentence preceding  
                            ``...g, when offered for transportation.''].
173.314(c), Note 8.......  173.314(c), Note 19 [1st sentence preceding  
                            ``...g, when offered for transportation.''].
179.7                                                                   
179.16...................  179.100-5.                                   
179.18...................  179.100-4.                                   
179.20                                                                  
179.22...................  179.100-21.                                  
                           179.105-8.                                   
                           179.200-25.                                  
                           179.203-3.                                   
Appendix A to Part 179...  179.105-5 (b) and (c).                       
Appendix B to Part 179...  179.105-4 (d) and (e).                       
Subpart F to Part 180                                                   
180.501                                                                 
180.503                                                                 
180.505                                                                 
180.507                                                                 
180.509                                                                 
180.511                                                                 
180.513                                                                 
180.515                                                                 
180.517                                                                 
180.519                                                                 
------------------------------------------------------------------------

IV. Review by Section Summary

Part 171

    Section 171.7(a)(3). The 49 CFR reference sections for the 
Association of American Railroads standards and for a Compressed Gas 
Association standard are added, revised or removed, as appropriate, to 
reflect the changes in this rulemaking.

Part 172

    Section 172.101. In the HMT, three special provisions are removed. 
Special Provision ``B41,'' appearing in column (7) of the entries for 
benzyl chloride, fluorosulfonic acid, and titanium tetrachloride is no 
longer necessary due to the new inspection and test intervals adopted 
in this final rule. Special Provision ``B43,'' appearing in column (7) 
of the entries for carbon dioxide, refrigerated liquid, hydrogen 
chloride, refrigerated liquid, and vinyl fluoride, 

[[Page 49067]]
inhibited, also is no longer necessary because of the new inspection 
and test requirements. For the Division 2.1 (flammable gas) entries 
ethyl chloride and ethyl methyl ether, Special Provision ``B63'' is 
removed, thus prohibiting the use of tank cars without head protection 
or thermal protection.
    Section 172.102. As discussed above, Special Provisions ``B41'' and 
``B43'' are removed. The inspection and test intervals (i.e., 5-3-1) 
specified in Special Provision ``B41'' and the nondestructive test 
requirements specified in Special Provision ``B43'' are incorporated 
into Subpart F of Part 180. Special Provision ``B63'' appears only in 
the entries ethyl chloride and ethyl methyl ether and, therefore, in 
paragraph (c), is removed. Special Provision ``B64'' is amended by 
changing the head-protection section reference ``Sec. 179.105-5'' to 
read ``Sec. 179.16,'' and Special Provision ``B79'' is amended by 
changing the head- and thermal-protection section references 
``Secs. 179.105-4 and 179.105-5'' to read ``Sec. 179.16 and 179.18''.

Part 173

    Section 173.31. The section heading is revised to read ``Use of 
Tank Cars.'' This section also is completely revised and reorganized 
for clarity.
    New paragraph (a)(1) corresponds to the language in the HMR for 
cargo tanks and portable tanks (see Secs. 173.32c(a) and 173.33(a)). 
The section also includes reference to certain ``AAR'' specification 
tank cars that are authorized for hazardous materials service in the 
HMR (see Secs. 173.241 and 173.242). When these tank cars are used for 
the transportation of hazardous materials, the tank cars must meet the 
minimum specification for new construction as required by AAR.
    New paragraph (a)(2) is essentially current Sec. 173.31(a)(4). The 
first, second, and third sentences are revised to clarify the use of 
the term ``authorized.'' Prior to December 19, 1957 (ICC Order No. 33), 
the regulations stated that:

    [T]ank cars and appurtenances may be used for the transportation 
of any commodity for which they are authorized, as indicated on the 
certificate of construction. When a car is to be used for the 
transportation of a commodity other than those approved on the 
certificate of construction, it must be approved for such loading by 
the A.A.R. Tank Car Committee. Changes in fittings or commodity 
stencilling required to transfer a car from one service to another 
as authorized on the certificate of construction, may be made only 
be the owner or owner's authorized agent * * *.

    As evidenced by the language above, the term ``authorized'' means 
those commodities designated on the certificate of construction and 
approved by the AAR Tank Car Committee. Order No. 33 changed the 
regulation by removing the phrase ``as indicated on the certificate of 
construction'' because many car owners did not have a certificate for 
older Class ARA-II (built prior to 1917), ARA-III (built prior to 
1927), and some ICC-103 (built after 1927) tank cars. Because this 
final rule requires that the original and subsequent tank car 
certificates must be maintained for the life of the car and transferred 
with ownership, RSPA is clarifying the purpose of this paragraph by 
inserting the phrase ``in this part and specified on its certificate of 
construction'' at the end of the first sentence. See Sec. 180.517. The 
second and third sentences are modified accordingly. Provisions 
contained in the fourth and fifth sentences of current 
Sec. 173.31(a)(4), stating that DOT 105A-W, 109A-W, 111A100W4, 112A-W, 
and 114A-W tank cars may be used for any commodity for which it is 
approved and may be stencilled accordingly, and that a tank car 
stencilled to indicate that it is authorized for one commodity may not 
be used for any other service, are removed. The stencilling requirement 
for these cars is optional and, therefore, not enforceable.
    New paragraph (a)(3) provides that no person may fill a tank car 
with a hazardous material when the tank car is overdue for periodic 
inspection and test. This provision allows the movement of tank cars 
containing hazardous material residue to a tank car facility for 
inspection and testing.
    New paragraph (a)(4) is current Sec. 173.31(a)(7). It removes 
reference to a compliance date, now past, and establishes that air 
brake equipment support attachments must be welded to pads instead of 
directly to the tank shell in conformance with Secs. 179.100-16 and 
179.200-19.
    New paragraph (a)(5) prohibits the use of an internal self-
energized manway that is located below the liquid level of the lading 
on a tank car, beginning on the effective date of this final rule. 
After the effective date of this final rule, an exemption would be 
required in order to continue to operate such a tank car. This 
provision was proposed paragraph (a)(22) in HM-175A.
    New paragraph (a)(6) is current Sec. 173.31(a)(3). It removes 
specific ``DOT'' class references and explains that any tank car of the 
same class with a higher tank test pressure than the tank car 
authorized in the HMR may be used. The paragraph is also simplified by 
specifying the hierarchy of the letters in the specification marking 
that describe special protective systems (e.g., ``J'' for thermally 
protected, jacketed cars; ``T'' for thermally protected, non-jacketed 
cars; ``S'' for cars with head shields but without thermal protection; 
and ``A'' for cars without protective systems).
    New paragraph (b)(1), concerning the use of coupler vertical 
restraint systems, is current Sec. 173.31(a)(5). It is revised to 
require all DOT specification tank cars and any other tank car used to 
transport hazardous material to be equipped with a coupler vertical 
restraint system. This revision also removes reference to a compliance 
date, now past, excepting DOT specification tank cars in nonhazardous 
materials service from being equipped with a coupler vertical restraint 
system.
    New paragraph (b)(2), concerning pressure relief devices, is 
current Secs. 173.31(a)(12) and 173.31(a)(15). This revision is 
simplified by using the term ``poisonous by inhalation'' (see 
Sec. 171.8) in place of the defining criteria.
    New paragraph (b)(3) requires head protection for all tank cars 
transporting Class 2 materials and tank cars constructed from aluminum 
or nickel plate. Tank cars currently equipped with half-head protection 
are excluded. The compliance period is 10 years from the effective date 
of this rule, except for class DOT 105 tank cars with less than 70 kl 
(18,500 gallon) capacity when used to transport a Division 2.1 
material, which have a compliance period of 5 years. This provision was 
proposed paragraph (a)(19) in HM-175A.
    New paragraph (b)(4) requires tank cars transporting Class 2 
materials to have thermal protection. Exceptions from the thermal 
protection standard are granted for ``chlorine,'' ``carbon dioxide, 
refrigerated liquid,'' and ``nitrous oxide, refrigerated liquid,'' and 
for tank car tank classes DOT 106, 107A, 110, and 113. This provision 
was proposed paragraph (a)(20) in HM-175A. In the NPRM, RSPA did not 
propose thermal protection for the commodities identified above (see 
proposed Sec. 173.314(k) and (o)). The compliance period is 10 years 
from the effective date of this final rule.
    New paragraph (b)(5) requires bottom-discontinuity protection for 
all existing tank cars transporting a hazardous material. The new 
protection requirements conform to paragraphs E9.00 and E10.00 of the 
AAR Specifications for Tank Cars, M-1002. Existing tank cars that 
conform to Appendix Y of the AAR Specifications for Tank Cars, M-1002, 
may continue in use. The compliance period is 10 years from the 
effective date of this final rule. 

[[Page 49068]]
This provision was proposed paragraph (a)(23) in HM-175A.
    New paragraph (b)(6) is added to require tank car owners to 
implement measures to ensure the phased-in completion of the 
modifications on each tank car subject to this final rule. As discussed 
earlier in this preamble, RSPA and FRA have several programs in place 
to improve the tank car fleet. Owners, therefore, should develop 
careful plans, procedures, and schedules to assure completion of the 
modifications before the regulatory compliance date. Paragraph (b)(6) 
also requires submission of a yearly progress report to FRA that shows 
the reporting mark of each tank car requiring modification, the type of 
modification required for each tank car during the previous year, and 
the total number of tank cars modified the previous year.
    New paragraph (c) was proposed as paragraph (d) in HM-201. This 
final rule revises the terms ``un-insulated'' to ``non-insulated,'' 
``ullage space or dome'' to ``vacant,'' and clarifies that this 
provision applies to cars in hazardous materials service only. A new 
provision is added in paragraph (c)(3) to require all tank cars 
transporting a PIH material to have a tank test pressure of at least 
20.7 Bar (300 psi). This provision is consistent with other regulations 
adopted under Docket HM-181 for PIH liquids.\19\ Also, several shipping 
names appearing in the opening paragraph are revised for consistency 
with the proper shipping name as shown in the Sec. 172.101 table.

    \19\For further information see Performance-Oriented Packaging, 
Docket HM-181, 55 FR 52402 (December 21, 1990). In general, liquid 
materials PIH in Hazard Zone A are assigned Special Provision B72 
and those in Hazard Zone B are assigned Special Provision B74. These 
two special provisions require the use of a 105S, 112J, or a 114J 
tank car having a tank test pressure greater than 18 Bar (300 psi).
---------------------------------------------------------------------------

    New paragraph (d) reinforces the inspection requirements that must 
be fulfilled before a tank car of hazardous materials is offered for 
transportation. These provisions were proposed paragraph (a)(4) and 
Sec. 174.68 in HM-201. These proposed requirements were revised and 
combined based on suggestions made by the commenters.
    In new paragraph (e), to clarify that the paragraph applies to 
materials that are poisonous by inhalation, the paragraph heading is 
revised to read ``Special requirements for materials poisonous by 
inhalation.''
    New paragraph (e)(1) concerns the use of heater coils. This 
provision is essentially current paragraph Sec. 173.31(a)(17). This 
provision was proposed paragraph (e) in HM-201.
    New paragraph (e)(2) requires that tank cars used for materials 
poisonous by inhalation must conform to at least a DOT 105S300W, 
105S300ALW, 112J340W, or 114J340W. This provision was proposed 
paragraph (a)(21) in HM-175A. It is made consistent with Special 
Provision B74 for liquid PIH materials in Zone B. The compliance period 
is 10 years from the effective date of this final rule.
    New paragraph (f) requires the use of a DOT 105S200W; a DOT 
112S200W with an 11-gauge steel jacket conforming to Sec. 179.100-4; a 
DOT 112S340W; or a DOT 112S200W tank car constructed from AAR steel 
specification TC-128, normalized, for the transportation of certain 
listed hazardous substances in Sec. 173.31(f) that pose a potential 
threat to human health and the environment. This provision was proposed 
paragraph (a)(24) in HM-175A.
    Section 173.314. In the table in paragraph (c), the entries are 
amended by removing references to the individual tank car 
specifications and adding references to the authorized tank car 
classes. This change ensures that Sec. 173.314 does not authorize a 
tank car having a tank test pressure below the regulatory minimum in 
Sec. 173.31(c). The current notes following the table are amended by 
redesignating, revising, or removing all tank car ``design 
requirements'' as follows (notes that apply to filling limits are 
retained):
    Note 1, no change.
    Note 2 is restated without substantial change and moved to 
Sec. 173.314(n).
    Note 3 and Note 4 are restated without substantial change and moved 
to Sec. 173.314(j), which is applicable to all materials having a 
primary or secondary Division 2.1 (flammable gas) hazard.
    Note 5 is restated without substantial change for clarity.
    Note 6 is restated without substantial change and moved to 
Sec. 173.314(o).
    Note 7, which restricts the transportation of multi-unit tank cars 
tanks (ton containers) to rail and highway only, is removed. RSPA 
believes no valid reason exists to restrict the transport of these 
units by water. A provision restricting the transport of multi-unit 
tank car tanks by air is unnecessary because all multi-unit tank car 
tanks exceed the maximum quantity limitations allowed by air.
    Note 8 is restated without substantial change and moved to 
Sec. 173.314(l).
    Note 9 is moved to Sec. 173.314(j) and made applicable to all 
materials with a primary or secondary Division 2.1 (flammable gas) 
hazard.
    Note 10 is restated without substantial change and moved to 
Sec. 173.314(m).
    Note 11 is restated without substantial change and included in 
Sec. 173.314(m).
    Note 12 is restated without substantial change. The filling density 
requirements are moved to Note 6, and the design requirements are moved 
to Sec. 173.314(k).
    Note 13 is removed to eliminate duplication of the marking 
requirements prescribed in Special Provision B12, Secs. 173.314(a)(5) 
and 172.330(a)(1)(i).
    Note 14 is removed because it is not referenced in the table.
    Note 15 is removed since it is included with the other design 
requirements applicable to tank cars used for materials having a 
primary or secondary Division 2.1 (flammable gas) hazard in 
Sec. 173.314(j).
    Note 16, which is currently reserved, is removed.
    Note 17, which references Sec. 173.314(g) is removed.
    Note 18 is restated without substantial change and moved to Note 7.
    Note 19 is restated without substantial change and moved to Note 8.
    Note 20 is restated without substantial change and moved to Note 4.
    Note 21 is restated without substantial change and moved to Note 3.
    Note 22, referencing the requirements in Sec. 173.245, is 
incorporated into the table under the entry ``Division 2.3, Zone A 
materials.''
    Note 23 and Note 24 are removed based on other changes in this 
final rule concerning the elimination of grandfather provisions.
    Note 25 is restated without substantial change and moved to Note 2.
    Note 29 and Note 30 are removed based on other changes in this 
final rule concerning the elimination of grandfather provisions.
    In addition, the table in Sec. 173.314(c) will reflect the tank car 
classes and not the specifications.
    Section 173.319. Paragraph (a)(4)(iii) is revised by removing a 
parenthetical reference to current Sec. 173.31(c)(13). A requirement 
contained in Sec. 173.31(c)(13) prescribing special retest requirements 
for class DOT-113 tank cars is revised and moved to new paragraph 
Sec. 173.319(e).
    Section 173.323. Paragraph (c)(1) is revised to require a tank test 
pressure of at least 20.7 Bar (300 psi) for ethylene oxide no later 
then 10 years after the effective date of this final rule. 
Authorization for the use of a DOT 111A100W4 and 111J100W4 tank car is 
removed.

Part 179

    Section 179.1. In paragraph (c), the section reference 
``Sec. 173.31'' is revised to read ``Sec. 180.507''. 

[[Page 49069]]

    Section 179.2. This section is amended by adding a definition for 
``Tank car facility.''
    Section 179.7. This section requires tank car facilities to have a 
Quality Assurance Program (QAP). Paragraph (a) sets forth performance 
standard for the program. Paragraphs (b)(1) through (b)(13) require 
that the QAP have certain minimum requirements. The term ``Enhanced 
visual imagery'' in paragraph (b)(10) is changed to read ``Optically-
aided visual inspection'' to correctly identify that the visual 
inspection method is ``optically aided.'' Optically-aided visual 
methods include the use of magnifiers, borescopes, fiberscopes, and 
machine vision technology (e.g., a video digitizer that converts images 
into digital form, and through image enhancement, image segmentation, 
and feature extraction, the computer classifies objects within the 
image). Paragraph (c) requires tank car facilities to ensure that only 
personnel qualified to perform a particular nondestructive inspection 
and test perform that operation. Paragraph (d) requires each tank car 
facility to have written procedures, covering inspection, fabrication, 
and repair operations as appropriate, for their employees. Paragraph 
(e) cross-references the training requirements in Subpart H of Part 
172. (Section 172.702 requires that a hazmat employer train each of its 
hazmat employees.) Paragraph (f) specifies the compliance date by which 
tank car facilities must have a QAP and written procedures in effect.
    Section 179.16. This new section contains the tank-head puncture-
resistance requirements found in current Secs. 179.100-23 and 179.105-
5.
    Section 179.18. This new section contains the thermal protection 
requirements found in current Sec. 179.105-4(a), (b), and (c). A 
requirement that the exterior of the tank car must be painted white in 
proposed Sec. 179.18(d) is moved to Sec. 179.101-1, Note 4 in this 
final rule. Editorial revisions are made to these requirements for 
clarity and for consistency with other changes in this final rule.
    Section 179.20. This new section contains bottom-discontinuity 
protection requirements. For new tank cars, bottom-discontinuity 
protection must conform to paragraphs E9.00 and E10.00 of the AAR 
Specifications for Tank Cars, M-1002.
    Section 179.22. New section 179.22 consolidates the marking 
requirements contained in current Secs. 179.100-21, 179.105-8, 179.200-
25, and 179.203-3. Based on this consolidation, Secs. 179.100-21, 
179.105-8, 179.200-25, and 179.203-3 are removed.
    Section 179.100-4. This section is amended by removing the phrase 
``except that a protective coating is not required when foam-in-place 
insulation that adheres to the tank or jacket is applied'' at the end 
of the first paragraph. This change is based on an AAR petition (P-
1050) to require protective coatings on the outside surface of the tank 
shell and the inside surface of the jacket.
    Section 179.100-21. The marking requirements contained in this 
section are consolidated with other marking requirements in new 
Sec. 179.22 and, as discussed earlier, Sec. 179.100-21 is removed.
    Section 179.100-23. The head protection requirements contained in 
this section are moved to Sec. 179.16(b), and, as discussed earlier, 
Sec. 179.100-23 is removed.
    Section 179.101-1. Certain editorial changes are made in 
Sec. 179.101-1, Note 4, for clarity and consistency with other changes 
made in this final rule. In the first sentence in Note 4, the section 
reference ``Sec. 179.100-4,'' which addresses insulated tank cars, is 
removed because Note 4 applies to non-insulated cars only. Note 4 is 
revised to clarify that there is no need to paint the tank white when a 
``thermal protection'' system is applied (consistent with current 
Sec. 179.105-4(g) and proposed Sec. 179.16 (d)), and to remove a 
requirement that tank cars in hydrogen fluoride service need to have a 
dark colored band in the top platform and fitting area because hydrogen 
fluoride is not a Class 2 (compressed gas) material. The last sentence 
is also removed because it is not a mandatory requirement.
    Section 179.103-1. Current paragraph (c), providing that a manway 
may be located other than at the top of the tank is no longer valid 
and, therefore, is removed and reserved.
    Section 179.103-2. Current paragraph (a) containing manway cover 
plate requirements is revised by removing the phrase ``may be of the 
self-energizing type and''. This change would prohibit the construction 
of tank cars with a self-energized manway located below the liquid 
level of the lading.
    Section 179.103-5. In current paragraph (a)(1), the first two 
sentences authorizing the location of a self-energizing manway below 
the liquid level of the tank is no longer valid and, therefore are 
removed.
    Section 179.105. Current Secs. 179.105 through 179.105-8 containing 
special requirements for class DOT 105S, 105J, 111J, 112S, 112J, 112T, 
114S, 114J, and 114T specification tank cars are removed because they 
are unnecessary. The applicable requirements concerning head protection 
and thermal protection are moved to Secs. 179.16, 179.18, and 
Appendices A and B to Part 179, as appropriate. The marking 
requirements are consolidated into Sec. 179.22. The requirement for 
exterior tank color was moved to footnote 4 of the Sec. 179.101-1 
table.
    Section 179.200-4. This section is amended by removing the phrase 
``except that a protective coating is not required when foam-in-place 
insulation that adheres to the tank or jacket is applied'' at the end 
of the first paragraph. This change is based on an AAR petition (P-
1050) to require protective coatings on the outside surface of the tank 
shell and the inside surface of the jacket.
    Section 179.200-25. The marking requirements contained in this 
section are consolidated with other marking requirements in 
Sec. 179.22, and, as discussed earlier, Sec. 179.200-25 is removed.
    Section 179.200-27. The head protection requirements are 
consolidated into Sec. 179.16. Therefore, current Sec. 179.200-27 is 
removed.
    Section 179.203. Current Secs. 179.203, 179.203-1, 179.203-2, and 
179.203-3 containing special requirements for class DOT 111 tank cars 
are unnecessary and are removed. The restriction in paragraph (c) 
against the use of class DOT 111 tank cars built after March 1, 1984, 
for the transportation of flammable gases or ethylene oxide is 
incorporated into Secs. 173.314 and 173.323. The applicable head-
protection and thermal-protection requirements are consolidated into 
Secs. 179.16 and 179.18, respectively. The marking requirements are 
consolidated into Sec. 179.22.
    Appendix A. The tank-head puncture-resistance test verification 
requirements in Sec. 179.105-5 paragraphs (b) and (c) are moved to this 
Appendix.
    Appendix B. This appendix contains the thermal-protection test-
verification requirements found in current Sec. 179.105-4(d), (e) and 
(f). These requirements are editorially revised for clarity.

Part 180

    Subpart F of Part 180. This subpart contains the qualification and 
maintenance requirements for tank cars.
    Section 180.501. Paragraph (a) specifies the applicability of the 
Subpart. Paragraph (b) specifies that any person who performs a 
function required by Subpart F of Part 180 must perform that function 
according to the regulations. 

[[Page 49070]]

    Section 180.503. This section defines certain terms used throughout 
the subpart.
    Section 180.505. This section requires each tank car facility 
performing repair work to have a QAP based on requirements in 
Sec. 179.7 for new car construction.
    Section 180.507. This section contains the continuing 
qualifications for existing tank cars that are no longer authorized for 
new construction, such as a class DOT 113A175W tank car. Paragraph (a) 
is essentially current Sec. 173.31(a)(1) except that it is revised to 
include non-specification tank cars that are currently authorized for 
the transportation of hazardous materials. Paragraphs (b)(1), (2), (3), 
and (4) are current Sec. 173.31(a)(2), (8), (9), and (10).
    Section 180.509. This section specifies the requirements for the 
periodic inspection and testing of tank cars. Paragraph (a)(1) requires 
each tank car facility to evaluate the tank car according to the 
``Acceptable results of inspections and tests'' as prescribed in 
Sec. 180.511. Paragraph (a)(2) requires marking each tank car passing a 
periodic inspection and test to indicate the date it passed this review 
and the due dates for the next inspection and test required in the new 
Sec. 180.515. Paragraph (a)(3) requires a written report for each tank 
car after it successfully passes an inspection and test. Paragraph (b) 
specifies unusual conditions that may require an inspection and test of 
tank cars. Paragraph (b)(1) requires an inspection and test if the tank 
shows evidence of abrasion, corrosion, cracks, dents, distortions, 
defects in welds, or any other condition unsafe for transportation. 
Paragraph (b)(2) requires an inspection and test if the tank car was in 
an accident and damaged to the extent that may adversely affect its 
capability to retain its contents (e.g., large dent or gouge in the 
tank shell). Paragraph (b)(3) requires an inspection and test if the 
tank was involved in a fire. Paragraph (b)(4) requires an inspection 
and test of either a single tank car or a design of tank cars operating 
in an unsafe condition, if required by FRA, based on the existence of a 
probable cause. Probable cause may include an inspection and test where 
FRA discovers a crack in a welded area, a wheel burn, or a large dent 
or bulge in the tank shell; it may also include a group of cars of a 
given design if FRA discovers problems apparently related to cars of 
that design.
    Paragraph (c) specifies the frequency with which inspections and 
tests must be performed on tank cars. Paragraph (c)(1) specifies the 
requirements for the inspection and hydrostatic test of class DOT 107 
tank cars and riveted tank cars. As noted above, the hydrostatic test 
is still effective for these tank cars since it will detect loose 
rivets and areas of metal distress. Paragraph (c)(2) requires an 
inspection for thermal integrity of class DOT 113 tank cars in place of 
the inspection and testing requirements in Subpart F of Part 180. This 
paragraph cross-references the requirements in Sec. 173.319(e). 
Paragraph (c)(3) specifies the inspection and test requirements for 
fusion welded tank cars. The intervals would vary depending upon 
whether or not the tank car was lined or coated and upon whether or not 
the car was transporting materials corrosive to the tank. For linings 
and coatings, this final rule requires a tank car facility to inspect 
the lining or coating based on the inspection and test intervals and 
techniques established by the lining or coating owner. The owner must 
establish an inspection interval and test technique based on the 
manufacturer's recommendations or the owner's knowledge of the life-
expectancy of the lining or coating.
    Paragraph (d) specifies the manner for conducting a visual 
inspection for each tank car. Paragraph (d)(1) requires an inspection 
of the tank car internally and externally for abrasion, corrosion, 
cracks, dents, distortions, defects in welds, or any other conditions 
unsafe for transportation. Paragraph (d)(2) requires the inspection of 
all piping, valves, fittings, and gaskets for corrosion and any other 
condition unsafe for transportation. Paragraph (d)(3) requires an 
inspection of the tank cars for missing or loose bolts, nuts, or other 
elements. Paragraph (d)(4) requires an inspection of all closures on 
the tank car for proper securement. The tank car facility would also 
inspect the protective housings for proper securement. Paragraph (d)(5) 
requires an inspection of the seats on excess flow valves. Paragraph 
(d)(6) requires an inspection of the markings on the tank car for 
legibility.
    Paragraph (e) requires that a structural integrity inspection and 
test shall include all transverse fillet welds greater than 0.64 cm 
(0.25 inch) within four feet of the bottom longitudinal center line; 
the termination of longitudinal fillet welds greater than 0.64 cm (0.25 
inch) within four feet of the bottom longitudinal center line; and all 
tank shell butt welds within two feet of the bottom longitudinal center 
line using one or more nondestructive test methods. The term ``Enhanced 
visual imagery'' is changed to read ``Optically-aided visual 
inspection'' to correctly identify that the visual inspection method is 
``optically aided.''
    Paragraph (f) requires thickness measurements to determine that the 
tank car is not below the minimum shell thickness.
    Paragraph (g) specifies the allowable shell thickness reductions. 
Paragraph (g)(1)(i) allows thickness reductions on carbon steel, 
stainless steel, aluminum, nickel, and manganese-molybdenum steels. 
Paragraph (g)(1)(ii) specifies the minimum shell and head thickness 
reductions for uniform and localized areas and Note 5 of the table is 
removed to disallow any reduction in the shell thickness for class DOT 
111A tank cars transporting ethylene oxide. As discussed earlier, this 
final rule prohibits the transportation of ethylene oxide in a class 
DOT 111 tank car.
    Paragraph (h)(1) requires the inspection of the safety systems on 
the tank, such as thermal protection systems, tank-head puncture-
resistance systems, and coupler vertical restraint systems, to ensure 
their integrity. Paragraph (h)(2) requires the inspection and test of 
re-closing pressure relief devices (safety valves).
    Paragraph (i) requires an inspection and test of tank cars with a 
lining or coating on the tank car. The inspection interval is 
determined by the owner based on the type of testing technique used, 
and knowledge of the material and tank car, but cannot exceed 10 years.
    Paragraph (j) requires a leakage pressure test of the tank car and 
appurtenances.
    Paragraph (k) allows the use of an alternative inspection and test 
procedure provided the procedure is based on a damage-tolerance 
evaluation, examined by the AAR Tank Car Committee, and approved by the 
Associate Administrator for Safety FRA.
    Paragraph (l) specifies the compliance date for the new inspection 
and test requirements.
    Section 180.511. This section specifies the acceptable results of 
inspections and tests. Paragraph (a) establishes that an acceptable 
visual inspection as one that shows no structural defect that may cause 
the tank car to fail (including leak) before the next inspection and 
test interval.
    Paragraph (b) establishes that an acceptable structural integrity 
inspection and test is one that shows no structural defect that may 
initiate cracks or propagate cracks and cause the tank car to fail 
before the next inspection and test interval.
    Paragraph (c) establishes that an acceptable service life shell 
thickness is one that shows no areas of the tank car 

[[Page 49071]]
below the minimum shell or head thickness allowed in Sec. 180.509(g).
    Paragraph (d) establishes that an acceptable safety system 
inspection is one that shows the systems (e.g., a thermal protection 
system) conform to Part 179.
    Paragraph (e) establishes that an acceptable inspection and test 
for lining and coatings as one that shows no holes or degraded areas.
    Paragraph (f) establishes that an acceptable inspection and test 
for a leakage pressure test as one that shows no indications of leakage 
in any product piping, fitting, or closure.
    Paragraph (g) establishes that an acceptable hydrostatic test, for 
class DOT 107 tank cars and riveted tank cars, is one that shows no 
leakage or deformations (i.e., distress) in the tank.
    Section 180.513. This section specifies that tank car repairs must 
conform to the requirements of Appendix R of AAR Specifications for 
Tank Cars. As proposed in HM-175A, the introductory text becomes 
paragraph (a), and Sec. 173.31 paragraph (f)(3) becomes Sec. 180.513 
paragraph (b). Section 180.513(b) requires that, unless the exterior 
tank car shell or interior tank car jacket has a protective coating, 
when the complete tank car jacket is removed to effect a repair, the 
exterior tank car shell and the interior tank car jacket must have a 
protective coating applied to prevent the deterioration of the tank 
shell and tank jacket.
    Section 180.515. This section specifies the marking requirements 
for tank cars after a successful tank inspection and test.
    Section 180.517. This section specifies the reporting and record 
retention requirements after a tank car has successfully completed its 
required inspection and test. Paragraph (a) requires the tank car owner 
to retain the certificate of construction of the tank car (AAR Form 4-
2) and related documentation certifying that the tank car conforms to 
the specification. The owner shall retain the documents for the period 
of ownership. Upon a change in ownership, Section 1.3.15 of AAR 
Specifications for Tank Cars requires the transfer of these documents 
to the new owner. Paragraph (b) specifies the inspection and test 
reporting requirements.
    Section 180.519. This section specifies the periodic test and 
inspection requirements for multi-unit tank cars (e.g., class DOT 106 
and 110 multi-unit tank cars).

V. Regulatory Analysis and Notices

A. Executive Order 12866 and DOT Regulatory Policies and Procedures

    This final rule is considered a significant regulatory action under 
section 3(f) of Executive Order 12866 and was reviewed by the Office of 
Management and Budget. The rule is considered significant under the 
Regulatory policies and Procedures of the Department of Transportation 
(44 FR 11034) because it affects a significant segment of the tank car 
industry. A regulatory evaluation is available for review in the 
docket.

B. Executive Order 12612

    This final rule has been analyzed in accordance with the principles 
and criteria contained in Executive Order 12612 (``Federalism''). 
Federal law expressly preempts State, local, and Indian tribe 
requirements applicable to the transportation of hazardous material 
that cover certain subjects and are not ``substantively the same'' as 
the Federal requirements. 49 U.S.C. 5125(b)(1). These covered subjects 
are:
    (A) the designation, description, and classification of hazardous 
material;
    (B) the packing, repacking, handling, labeling, marking, and 
placarding of hazardous material;
    (C) the preparation, execution, and use of shipping documents 
related to hazardous material and requirements respecting the number, 
contents, and placement of those documents;
    (D) the written notification, recording, and reporting of the 
unintentional release in transportation of hazardous material; or
    (E) the design, manufacturing, fabricating, marking, maintenance, 
reconditioning, repairing, or testing of a packaging or a container 
which is represented, marked, certified, or sold as qualified for use 
in transporting hazardous material.
    This final rule addresses the design, manufacturing, repairing, and 
other requirements for packages represented as qualified for use in the 
transportation of hazardous material. Therefore, this final rule 
preempts State, local, or Indian tribe requirements that are not 
``substantively the same'' as Federal requirements on these subjects. 
Section 5125(b)(2) of Title 49 U.S.C. provides that when DOT issues a 
regulation concerning any of the covered subjects after November 16, 
1990, DOT must determine and publish in the Federal Register the 
effective date of Federal preemption. The effective date may not be 
earlier that the 90th day following the date of issuance of the final 
rule and no later than two years after the date of issuance. RSPA has 
determined that the effective date of Federal preemption of this final 
rule will be 90 days after publication in the Federal Register.
    Because RSPA lacks discretion in this area, preparation of a 
federalism assessment is not warranted.

C. Regulatory Flexibility Act

    I certify that this final rule will not have a significant economic 
impact on a substantial number of small entities. The entities affected 
by the rule are involved in tank car leasing, maintenance, repair and 
use. There are no direct or indirect adverse economic impacts for small 
units of government, businesses, or other organizations.

D. Paperwork Reduction Act

    The requirements for information collection have been approved by 
the Office of Management and Budget (OMB) under the provision of the 
Paperwork Reduction Act of 1980 (Pub. L. 95-511) under OMB control 
number 2137-0559.

E. Regulation Identifier Number (RIN)

    A regulation identifier number (RIN) is assigned to each regulatory 
action listed in the Unified Agenda of Federal Regulations. The 
Regulatory Information Service Center publishes the Unified Agenda in 
April and October of each year. The RIN numbers contained in the 
heading of this document can be used to cross-reference this action 
with the Unified Agenda.

List of Subjects

49 CFR Part 171

    Exports, Hazardous materials transportation, Hazardous waste, 
Imports, Incorporation by reference, Reporting and recordkeeping 
requirements.

49 CFR Part 172

    Hazardous materials transportation, Hazardous waste, Labels, 
Markings, Packaging and containers, Reporting and recordkeeping 
requirements.

49 CFR Part 173

    Hazardous materials transportation, Incorporation by reference, 
Packaging and containers, Radioactive materials, Reporting and 
recordkeeping requirements, Uranium.

49 CFR Part 179

    Hazardous materials transportation, Incorporation by reference, 
Railroad safety, Reporting and recordkeeping requirements. 

[[Page 49072]]


49 CFR Part 180

    Hazardous materials transportation, Incorporation by reference, 
Motor carriers, Motor vehicle safety, Packaging and containers, 
Railroad safety, Reporting and recordkeeping requirements.
    In consideration of the foregoing, 49 CFR Chapter I is amended as 
follows:

PART 171--GENERAL INFORMATION, REGULATIONS, AND DEFINITIONS

    1. The authority citation for part 171 continues to read as 
follows:

    Authority: 49 U.S.C. 5101-5127; 49 CFR 1.53.


Sec. 171.7  [Amended]

    2. In Sec. 171.7, in paragraph (a)(3) Table, the following changes 
are made:
    a. Under the Association of American Railroads, for the entry ``AAR 
Manual of Standards and Recommended Practices, Section C-Part III, 
Specifications for Tank Cars, Specification M-1002, September, 1992'' 
in column 2, the references are revised to read ``173.31; 174.63; 
179.6; 179.7; 179.12; 179.16; 179.20; 179.22; 179.100; 179.101; 
179.102; 179.103; 179.200; 179.201; 179.220; 179.300; 179.400; 180.509; 
180.513; 180.515; 180.517.''.
    b. Under the Association of American Railroads, for the entry ``AAR 
Specifications for Design, Fabrication and Construction of Freight 
Cars, Volume 1, 1988'' in column 2, the reference is revised to read 
``179.16.''.
    c. Under the Compressed Gas Association, Inc., for the entry ``CGA 
Pamphlet C-6, Standards for Visual Inspection of Compressed Gas 
Cylinders, 1984'' in column 2, the reference is revised to read 
``173.34; 180.519.''.

PART 172--HAZARDOUS MATERIALS TABLE, SPECIAL PROVISIONS, HAZARDOUS 
MATERIALS COMMUNICATIONS, EMERGENCY RESPONSE INFORMATION, AND 
TRAINING REQUIREMENTS

    3. The authority citation for part 172 continues to read as 
follows:

    Authority: 49 U.S.C. 5101-5127; 49 CFR 1.53.


Sec. 172.101  [Amended]

    4. In Sec. 172.101, in the Hazardous Materials Table, the following 
changes are made:
    a. For the entries ``Benzyl chloride'', ``Fluorosulfonic acid'', 
and ``Titanium tetrachloride'', in Column (7), Special Provision 
``B41,'' is removed.
    b. For the entries ``Carbon dioxide, refrigerated liquid'' and 
``Vinyl fluoride inhibited'', in Column (7), Special Provision ``B43'' 
is removed.
    c. For the entry ``Hydrogen chloride, refrigerated liquid'', in 
Column (7), Special Provision ``, B43'' is removed.
    d. For the entry ``Ethyl methyl ether'', in column (7), Special 
Provision ``B63'' is removed.
    e. For the entry ``Ethyl chloride'', in column (7), Special 
Provision ``B63,'' is removed.


Sec. 172.102  [Amended]

    5. In Sec. 172.102, in paragraph (c)(3), the following changes are 
made:
    a. Special Provision ``B41'' is removed.
    b. Special Provision ``B43'' is removed.
    c. Special Provision ``B63'' is removed.
    d. Special Provision ``B64'' is amended by revising the section 
reference ``Sec. 179.105-5'' to read ``Sec. 179.16''.
    e. Special Provision ``B79'' is amended by revising the section 
references ``Secs. 179.105-4 and 179.105-5'' to read ``Secs. 179.16 and 
179.18''.

PART 173--SHIPPERS--GENERAL REQUIREMENTS FOR SHIPMENTS AND 
PACKAGINGS

    6. The authority citation for part 173 continues to read as 
follows:

    Authority: 49 U.S.C. 5101-5127; 49 CFR 1.53.

    7. Section 173.31 is revised to read as follows:


Sec. 173.31  Use of tank cars.

    (a) General. (1) No person may offer a hazardous material for 
transportation in a tank car unless the tank car meets the applicable 
specification and packaging requirements of this subchapter or, when 
this subchapter authorizes the use of an non-DOT specification tank 
car, the applicable specification to which the tank was constructed.
    (2) Tank cars and appurtenances may be used for the transportation 
of any commodity for which they are authorized in this part and 
specified on the certificate of construction (AAR Form 4-2 or by 
addendum on Form R-1). See Sec. 179.5 of this subchapter. Transfer of a 
tank car from one specified service on its certificate of construction 
to another may be made only by the owner or with the owner's 
authorization. A tank car proposed for a commodity service other than 
specified on its certificate of construction must be approved for such 
service by the AAR's Tank Car Committee.
    (3) No person may fill a tank car overdue for periodic inspection 
with a hazardous material and then offer it for transportation. Any 
tank car marked as meeting a DOT specification and any non-
specification tank car transporting a hazardous material must have a 
periodic inspection and test conforming to Subpart F of Part 180 of 
this subchapter.
    (4) No railroad tank car, regardless of its construction date, may 
be used for the transportation in commerce of any hazardous material 
unless the air brake equipment support attachments of such tank car 
conform to the standards for attachments set forth in Secs. 179.100-16 
and 179.200-19 of this subchapter.
    (5) No railroad tank car, regardless of its construction date, may 
be used for the transportation in commerce of any hazardous material 
with a self-energized manway located below the liquid level of the 
lading.
    (6) Unless otherwise specifically provided in this part:
    (i) When this subchapter designates a specific specification tank 
car, the same class tank car with a higher marked test pressure also 
may be used.
    (ii) When the tank car specification delimiter is an ``A,'' 
offerors may also use tank cars with a delimiter ``S,'' ``J'' or ``T''.
    (iii) When the tank car specification delimiter is an ``S,'' 
offerors may also use tank cars with a delimiter ``J'' or ``T''.
    (iv) When a tank car specification delimiter is a ``T'' offerors 
may also use tank cars with a delimiter of ``J''.
    (v) When a tank car specification delimiter is a ``J'', offerors 
may not use a tank car with any other specification delimiter.
    (b) Safety systems--(1) Coupler vertical restraint. Each tank car 
conforming to a DOT specification and any other tank car used for 
transportation of a hazardous material must be equipped with a coupler 
vertical restraint system that meets the requirements of Sec. 179.14 of 
this subchapter.
    (2) Pressure relief devices. (i) Pressure relief devices on tank 
cars must conform to Part 179 of this subchapter.
    (ii) Except for shipments of chloroprene, inhibited, in class DOT 
115 tank cars, tank cars used for materials meeting the definition for 
Division 6.1 liquid, Packing Group I or II, Class 2 materials, or Class 
3 or 4 liquids, must have self-closing pressure relief devices. 
However, a tank car built before January 1, 1991, and equipped with a 
non-closing pressure relief device may be used to transport a Division 
6.1 or Class 4 liquid if the liquid is not poisonous by inhalation. 
Unless otherwise specifically provided in this 

[[Page 49073]]
subchapter, frangible discs may not have breather holes.
    (3) Tank-head puncture-resistance requirements. The following tank 
cars must have a tank-head puncture-resistance system that conforms to 
the requirements in Sec. 179.16 of this subchapter, or to the 
corresponding requirements in effect at the time of installation:
    (i) Tank cars transporting a Class 2 material.
    (ii) Tank cars constructed from aluminum or nickel plate that are 
used to transport hazardous material.
    (iii) Except as provided in paragraph (b)(3)(iv) of this section, 
tank cars not requiring a tank-head puncture-resistance system prior to 
July 1, 1996, must have a tank-head puncture-resistance system 
installed no later than July 1, 2006.
    (iv) Class DOT 105A tank cars built prior to September 1, 1981, 
having a tank capacity less than 70 kl (18,500 gallons), and used to 
transport a Division 2.1 (flammable gas) material, must have a tank-
head puncture-resistant system installed no later than July 1, 2001.
    (4) Thermal protection requirements. The following tank cars must 
have thermal protection that conforms to the requirements of 
Sec. 179.18 of this subchapter:
    (i) Tank cars transporting a Class 2 material, except for class DOT 
105A tank cars transporting chlorine, carbon dioxide refrigerated 
liquid, or nitrous oxide refrigerated liquid, and class DOT 106, 107A, 
110, and 113 tank cars.
    (ii) Tank cars not requiring thermal protection prior to July 1, 
1996, must conform to this section no later than July 1, 2006.
    (5) Bottom-discontinuity protection requirements. No person may 
offer for transportation a hazardous material in a tank car unless the 
tank car has bottom-discontinuity protection that conforms to the 
requirements of E9.00 and E10.00 of the AAR Specifications for Tank 
Cars. Tank cars not requiring bottom-discontinuity protection under the 
terms of Appendix Y of the AAR Specifications for Tank Cars as of July 
1, 1996, must conform to these requirements no later than July 1, 2006. 
Tank cars modified before July 1, 1996, may conform to the bottom-
discontinuity protection requirements of Appendix Y of the 1992 edition 
of the AAR Specifications for Tank Cars.
    (6) Scheduling of modifications and progress reporting. The date of 
conformance for the continued use of tank cars subject to paragraphs 
(b)(3), (b)(4), (b)(5), (e)(2), and (f) of this section and 
Secs. 173.314(j) and 173.323(c)(1) is subject to the following 
conditions and limitations.
    (i) Each tank car owner shall modify, reassign, retire, or remove 
at least 50 percent of their in-service tank car fleet within the first 
half of the compliance period and the remainder of their in-service 
tank car fleet during the second half of the compliance period.
    (ii) Before July 1 of each year, each owner shall submit to the 
Associate Administrator for Safety, FRA (Attention: RRS-12) a progress 
report that shows the reporting mark of each tank car, the status of 
each tank car during the previous year, and the total number of those 
tank cars modified reassigned, retired, or removed the previous year.
    (c) Tank car test pressure. A tank car used for the transportation 
of a hazardous material must have a tank test pressure equal to or 
greater than the greatest of the following:
    (1) Except for shipments of carbon dioxide, anhydrous hydrogen 
chloride, vinyl fluoride, ethylene, or hydrogen, 133 percent of the sum 
of lading vapor pressure at the reference temperature of 46  deg.C (115 
 deg.F) for non-insulated tank cars or 41  deg.C (105  deg.F) for 
insulated tank cars plus static head, plus gas padding pressure in the 
vacant space of a tank car;
    (2) 133 percent of the maximum loading or unloading pressure, 
whichever is greater;
    (3) 20.7 Bar (300 psi) for materials that are poisonous by 
inhalation;
    (4) The minimum pressure prescribed by the specification in Part 
179 of this subchapter; or
    (5) The minimum test pressure prescribed for the specific hazardous 
material in the applicable packaging section in Subpart F or G of this 
Part.
    (d) Examination before shipping. (1) No person may offer for 
transportation a tank car containing a hazardous material or a residue 
of a hazardous material unless that person determines that the tank car 
is in proper condition and safe for transportation. As a minimum, each 
person offering a tank car for transportation must perform an external 
visual inspection that includes:
    (i) Except where insulation or a thermal protection system 
precludes an inspection, the tank shell and heads for abrasion, 
corrosion, cracks, dents, distortions, defects in welds, or any other 
condition that makes the tank car unsafe for transportation;
    (ii) The piping, valves, fittings, and gaskets for corrosion, 
damage, or any other condition that makes the tank car unsafe for 
transportation;
    (iii) For missing or loose bolts, nuts, or elements that make the 
tank car unsafe for transportation;
    (iv) All closures on tank cars and determine that the closures and 
all fastenings securing them are properly tightened in place by the use 
of a bar, wrench, or other suitable tool;
    (v) Protective housings for proper securement;
    (vi) The pressure relief device, including a careful inspection of 
the frangible disc in non-closing pressure relief devices, for 
corrosion or damage that may alter the intended operation of the 
device;
    (vii) Each tell-tale indicator after filling and prior to 
transportation to ensure the integrity of the frangible disc;
    (viii) The external thermal protection system, tank head puncture 
resistance system, coupler vertical restraint system, and other safety 
systems for conditions that make the tank car unsafe for 
transportation;
    (ix) The required markings on the tank car for legibility; and
    (x) The periodic inspection date markings to ensure that the 
inspection and test intervals are within the prescribed intervals.
    (2) Closures on tank cars are required, under this subchapter, to 
be designed and closed so that under conditions normally incident to 
transportation, including the effects of temperature and vibration, 
there will be no identifiable release of a hazardous material to the 
environment. In any action brought to enforce this section, the lack of 
securement of any closure to a tool-tight condition, detected at any 
point, will establish a rebuttable presumption that a proper inspection 
was not performed by the offeror of the car. That presumption may be 
rebutted only by evidence establishing that the car was subjected to 
abnormal treatment, e.g., a derailment or vandalism.
    (e) Special requirements for materials poisonous by inhalation--(1) 
Interior heater coils. Tank cars used for materials poisonous by 
inhalation may not have interior heater coils.
    (2) Tank car specifications. Except as otherwise provided in this 
subchapter, tank cars used for materials poisonous by inhalation must 
conform to at least a DOT 105S300W, 105S300ALW, 112J340W, or 114J340W 
specification. Hazardous materials not requiring the use of a class DOT 
105S300W, 105S300ALW, 112J340W, or 114J340W tank car prior to July 1, 
1996, must be transported in one of these specifications no later than 
July 1, 2006.
    (f) Special requirements for hazardous substances. (1) Before July 
1, 2006, each tank car used for transportation of a 

[[Page 49074]]
hazardous substance listed in paragraph (f)(2) of this section must 
conform to DOT 105S200W, DOT 112S200W with an 11-gauge steel jacket, 
DOT 112S340W, or DOT 112S200W constructed from AAR steel specification 
TC-128, normalized.
    (2) List of hazardous substances. Hazardous substances for which 
the provisions of this paragraph (f) apply are as follows:

Aldrin
Allyl chloride
alpha-BHC
beta-BHC
delta-BHC
gamma-BHC
Bis(2-chloroethyl) ether
Bromoform
Carbon tetrachloride
Chlordane
p-Chloroaniline
Chlorobenzene
Chlorobenzilate
p-Chloro-m-cresol
2-Chloroethyl vinyl ether
Chloroform
2-Chloronapthalene
o-Chlorophenol
3-Chloropropionitrile
DDE
DDT
1,2-Dibromo-3-chloropropane
m-Dichlorobenzene
o-Dichlorobenzene
p-Dichlorobenzene
3,3'-Dichlorobenzidine
1,4-Dichloro-2-butene
1,1-Dichloroethane
1,2-Dichloroethane
1,1-Dichloroethylene
Dichloroisopropyl ether
Dichloromethane @
2,4-Dichlorophenol
2,6-Dichlorophenol
1,2-Dichloropropane
1,3-Dichloropropene
Dieldrin
alpha-Endosulfan
beta-Endosulfan
Endrin
Endrin aldehyde
Heptachlor
Heptachlor epoxide
Hexachlorobenzene
Hexachlorobutadiene
Hexachloroethane
Hexachlorophene
Hexachloropropene
Isodrin
Kepone
Methoxychlor
4,4'-Methylenebis(2-chloroaniline)
Methylene bromide
Pentachlorobenzene
Pentachloroethane
Pentachloronitrobenzene (PCNB)
Pentachlorophenol
Polychlorinated biphenyls (PCBs)
Pronamide
Silvex (2,4,5-TP)
2,4,5-T
TDE
1,2,4,5-Tetrachlorobenzene
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD)
Tetrachloroethane
Tetrachloroethylene
2,3,4,6-Tetrachlorophenol
Toxaphene
1,2,4-Trichlorobenzene
1,1,1-Trichloroethane
1,1,2-Trichloroethane
Trichloroethylene
2,4,5-Trichlorophenol
2,4,6-Trichlorophenol
Tris(2,3-dibromopropyl) phosphate

    8. In Sec. 173.314, the section heading and paragraph (c) are 
revised, and paragraphs (j) through (o) are added to read as follows:


Sec. 173.314  Compressed gases in tank cars and multi-unit tank cars.

* * * * *
    (c) Authorized gases, filling limits for tank cars. A compressed 
gas in a tank car or a multi-unit tank car must be offered for 
transportation in accordance with Sec. 173.31 and this section. The 
named gases must be loaded and offered for transportation in accordance 
with the following table:

----------------------------------------------------------------------------------------------------------------
                                                          Outage and filling                                    
                  Proper shipping name                    limits (see note 1)      Authorized tank car class    
----------------------------------------------------------------------------------------------------------------
Ammonia, anhydrous, or ammonia solutions > 50 percent    Note 2..............  105, 112, 114.                   
 ammonia.                                                                                                       
                                                         Note 3..............  106.                             
Ammonia solutions with > 35 percent, but  50  Note 3..............  105, 109, 112, 114.              
 percent ammonia by mass.                                                                                       
Argon, compressed......................................  Note 4..............  107.                             
Boron trichloride......................................  Note 3..............  105, 106.                        
Carbon dioxide, refrigerated liquid....................  Note 5..............  105.                             
Chlorine...............................................  Note 6..............  105.                             
                                                         125.................  106.                             
Chlorine trifluoride...................................  Note 3..............  106, 110.                        
Chlorine pentafluoride.................................  Note 3..............  106, 110.                        
Dimethyl ether.........................................  Note 3..............  105, 106, 110.                   
Dimethylamine, anhydrous...............................  Note 3..............  105, 106, 112.                   
Dinitrogen tetroxide, inhibited........................  Note 3..............  105, 106, 110.                   
Division 2.1 materials not specifically identified in    Note 3..............  105, 106, 110, 112, 114.         
 this table.                                                                                                    
Division 2.2 materials not specifically identified in    Note 3..............  105, 106, 109, 110, 112, 114.    
 this table.                                                                                                    
Division 2.3 Zone A materials not specifically           None................  See Sec. 173.245.                
 identified in this table.                                                                                      
Division 2.3 Zone B materials not specifically           Note 3..............  105, 106, 110, 112, 114.         
 identified in this table.                                                                                      
Division 2.3 Zone C materials not specifically           Note 3..............  105, 106, 110, 112, 114.         
 identified in this table.                                                                                      
Division 2.3 Zone D materials not specifically           Note 3..............  105, 106, 109, 110, 112, 114.    
 identified in this table.                                                                                      
Ethylamine.............................................  Note 3..............  105, 106, 110, 112, 114.         
Helium, compressed.....................................  Note 4..............  107.                             
Hydrogen...............................................  Note 4..............  107.                             
Hydrogen chloride, refrigerated liquid.................  Note 7..............  105.                             
Hydrogen sulphide, liquified...........................  68..................  106.                             
Methyl bromide.........................................  Note 3..............  105, 106.                        
Methyl chloride........................................  Note 3..............  105, 106, 112.                   
Methyl mercaptan.......................................  Note 3..............  105, 106.                        
Methylamine, anhydrous.................................  Note 3..............  105, 106, 112.                   
Nitrogen, compressed...................................  Note 4..............  107.                             
Nitrosyl chloride......................................  124.................  105.                             
                                                         110.................  106.                             

[[Page 49075]]
                                                                                                                
Nitrous oxide, refrigerated liquid.....................  Note 5..............  105.                             
Oxygen, compressed.....................................  Note 4..............  107.                             
Phosgene...............................................  Note 3..............  106.                             
Sulfur dioxide, liquified..............................  125.................  105, 106, 110.                   
Sulfuryl fluoride......................................  120.................  105.                             
Vinyl fluoride, inhibited..............................  Note 8..............  105.                             
----------------------------------------------------------------------------------------------------------------
Notes:                                                                                                          
1. The percent filling density for liquefied gases is hereby defined as the ratio of the mass of gas in the tank
  to the mass of water the tank will hold. For determining the water capacity of the tank in kilograms, the mass
  of one liter (0.264 gallons) of water at 15.55  deg.C (60  deg.F.) in air is 1 kg (2.204 pounds).             
2. The liquefied gas must be so loaded so that the outage is at least two percent of the total capacity of the  
  tank at the reference temperature of 46  deg.C (115  deg.F.) for non-insulated tanks and 41  deg.C (105       
  deg.F.) for insulated tanks.                                                                                  
3. The requirements of Sec. 173.24b(a) apply.                                                                   
4. The gas pressure at 54.44  deg.C (130  deg.F.) in any non-insulated tank car may not exceed 7/10 of the      
  marked test pressure, except that a tank may be charged with helium to a pressure 10 percent in excess of the 
  marked maximum gas pressure at 54.44  deg.C (130  deg.F.) of each tank.                                       
5. The liquid portion of the gas at -17.77  deg.C (0  deg.F.) must not completely fill the tank.                
6. The maximum permitted filling density is 125 percent. The quantity of chlorine loaded into a single unit-tank
  car may not be loaded in excess of the normal lading weights nor in excess of 81.65 Mg (90 tons).             
7. 89 percent maximum to 80.1 percent minimum at a test pressure of 6.2 Bar (90 psi).                           
8. 59.6 percent maximum to 53.6 percent minimum at a test pressure of 7.2 Bar (105 psi).                        


* * * * *
    (j) Special requirements for materials having a primary or 
secondary Division 2.1 (flammable gas) hazard. For single unit tank 
cars, interior pipes of loading and unloading valves, sampling devices, 
and gauging devices with an opening for the passage of the lading 
exceeding 1.52 mm (0.060 inch) diameter must be equipped with excess 
flow valves. For single unit tank cars constructed before January 1, 
1972, gauging devices must conform to this paragraph by no later than 
July 1, 2006. The protective housing cover must be provided with an 
opening, with a weatherproof cover, above each safety relief valve that 
is concentric with the discharge of the safety relief valve and that 
has an area at least equal to the valve outlet area. Class DOT 109 tank 
cars and tank cars manufactured from aluminum or nickel plate are not 
authorized.
    (k) Special requirements for chlorine. Tank cars built after 
September 30, 1991, must have an insulation system consisting of 5.08 
cm (2 inches) glass fiber placed over 5.08 cm (2 inches) of ceramic 
fiber. Tank cars must have excess flow valves on the interior pipes of 
liquid discharge valves. Tank cars constructed to a DOT 105A500W 
specification may be marked as a DOT 105A300W specification with the 
size and type of safety relief valves required by the marked 
specification.
    (l) Special requirements for hydrogen sulphide. Each multi-unit 
tank car must be equipped with adequate safety relief devices of the 
fusible plug type having a yield temperature not over 76.66  deg.C (170 
 deg.F.), and not less than 69.44  deg.C (157  deg.F.). Each device 
must be resistant to extrusion of the fusible alloy and leak tight at 
55  deg.C (130  deg.F.). Each valve outlet must be sealed by a threaded 
solid plug. In addition, all valves must be protected by a metal cover.
    (m) Special requirements for nitrosyl chloride. Single unit tank 
cars and their associated service equipment, such as venting, loading 
and unloading valves, and safety relief valves, must be made of metal 
or clad with a material that is not subject to rapid deterioration by 
the lading. Multi-unit tank car tanks must be nickel-clad and have 
safety relief devices incorporating a fusible plug having a yield 
temperature of 79.44  deg.C (175  deg.F.). Safety relief devices must 
be vapor tight at 54.44  deg.C (130  deg.F.).
    (n) Special requirements for hydrogen chloride. Each tank car must 
be equipped with one or more safety relief devices. The discharge 
outlet for each safety relief device must be connected to a manifold 
having a non-obstructed discharge area of at least 1.5 times the total 
discharge area of the safety relief devices connected to the manifold. 
All manifolds must be connected to a single common header having a non-
obstructed discharge pointing upward and extending above the top of the 
car. The header and the header outlet must each have a non-obstructed 
discharge area at least equal to the total discharge area of the 
manifolds connected to the header. The header outlet must be equipped 
with an ignition device that will instantly ignite any hydrogen 
discharged through the safety relief device.
    (o) Special requirements for carbon dioxide, refrigerated liquid 
and nitrous oxide, refrigerated liquid. Each tank car must have an 
insulation system so that the thermal conductance is not more than 
0.613 kilojoules per hour, per square meter, per degree Celsius (0.03 
B.t.u. per square foot per hour, per degree Fahrenheit) temperature 
differential. Each tank car must be equipped with one safety relief 
valve set to open at a pressure not exceeding 75 percent of the tank 
test pressure and one frangible disc design to burst at a pressure less 
than the tank test pressure. The discharge capacity of each safety 
relief device must be sufficient to prevent building up of pressure in 
the tank in excess of 82.5 percent of the test pressure of the tank. 
Tanks must be equipped with two regulating valves set to open at a 
pressure not to exceed 24.1 Bar (350 psi) on DOT 105A500W tanks and at 
a pressure not to exceed 27.6 Bar (400 psi) on DOT 105A600W tanks. Each 
regulating valve and safety relief device must have its final discharge 
piped to the outside of the protective housing.
    9. In Sec. 173.319, new paragraph (e) is added to read as follows:


Sec. 173.319  Cryogenic liquids in tank cars.

* * * * *
    (e) Special requirements for class DOT 113 tank cars. (1) A class 
DOT-113 tank car need not be periodically pressure tested; however, 
each shipment must be monitored to determine the average daily pressure 
rise in the tank car. If the average daily pressure rise during any 
shipment exceeds 0.2 Bar (3 psi) per day, the tank must be tested for 
thermal integrity prior to any subsequent shipment.
    (2) Thermal integrity test. When required by paragraph (e)(1) of 
this section, either of the following thermal integrity tests may be 
used:
    (i) Pressure rise test. The pressure rise in the tank may not 
exceed 0.34 Bar (5 psi) in 24 hours. When the pressure rise test is 
performed, the absolute pressure in the annular space of the loaded 
tank car may not exceed 75 microns of 

[[Page 49076]]
mercury at the beginning of the test and may not increase more than 25 
microns during the 24-hour period; or
    (ii) Calculated heat transfer rate test. The insulation system must 
be performance tested as prescribed in Sec. 179.400-4 of this 
subchapter. When the calculated heat transfer rate test is performed, 
the absolute pressure in the annular space of the loaded tank car may 
not exceed 75 microns of mercury at the beginning of the test and may 
not increase more than 25 microns during the 24-hour period. The 
calculated heat transfer rate in 24 hours may not exceed:
    (A) 120 percent of the appropriate standard heat transfer rate 
specified in Sec. 179.401-1 of this subchapter, for DOT-113A60W and 
DOT-113C120W tank cars;
    (B) 122.808 joules (0.1164 Btu/day/lb.) of inner tank car water 
capacity, for DOT-113A175W tank cars;
    (C) 345.215 joules (0.3272 Btu/day/lb.) of inner tank car water 
capacity, for DOT-113C60W and 113D60W tank cars; or
    (D) 500.09 joules (0.4740 Btu/day/lb.) of inner tank car water 
capacity, for DOT-113D120W tank cars.
    (3) A tank car that fails a test prescribed in paragraph (e)(2) of 
this section must be removed from hazardous materials service. A tank 
car removed from hazardous materials service because it failed a test 
prescribed in paragraph (e)(2) of this section may not be used to 
transport a hazardous material unless the tank car conforms to all 
applicable requirements of this subchapter.
    (4) Each frangible disc must be replaced with a new frangible disc 
every 12 months, and the replacement date must be marked on the car 
near the pressure relief valve information.
    (5) Pressure relief valves and alternate pressure relief valves 
must be tested every five years. The start-to-discharge pressure and 
vapor tight pressure requirements for the pressure relief valves must 
be as specified in Sec. 179.401-1 of this subchapter. The alternate 
pressure relief device values specified in Sec. 179.401-1 of this 
subchapter for a DOT-113C120W tank car apply to a DOT-113D120W tank 
car.


Sec. 173.319  [Amended]

    10. In addition, in Sec. 173.319, in paragraph (a)(4)(iii), the 
parenthetical reference ``(see Sec. 173.31(c)(13))'' is removed.
    11. In Sec. 173.323, paragraph (c)(1) is revised to read as 
follows:


Sec. 173.323  Ethylene oxide.

* * * * *
    (c) * * *
    (1) Tank cars. Class DOT 105J tank cars: Notwithstanding the 
requirements of Sec. 173.31(c), each tank car must have a tank test 
pressure of at least 20.7 Bar (300 psi) no later than July 1, 2006.
* * * * *

PART 179--SPECIFICATIONS FOR TANK CARS

    2. The authority citation for part 179 continues to read as 
follows:

    Authority: 49 App. U.S.C. 5101-5127; 49 CFR 1.53.


Sec. 179.1  [Amended]

    13. In Sec. 179.1, in paragraph (c), the section reference 
``Sec. 173.31'' is revised to read ``Sec. 180.507''.
    14. In Sec. 179.2, paragraph (a)(10) is redesignated as paragraph 
(a)(11) and a new paragraph (a)(10) is added to read as follows:


Sec. 179.2  Definitions and abbreviations.

    (a) * * *
    (10) Tank car facility means an entity that manufactures, repairs, 
inspects, or tests a tank car to ensure that the tank car conforms to 
this part and subpart F of part 180 of this subchapter, that alters the 
certificate of construction of the tank car, that ensures the 
continuing qualification of a tank car by performing a function 
prescribed in parts 179 or 180 of this subchapter, or that makes any 
representation indicating compliance with one or more of the 
requirements of parts 179 or 180 of this subchapter.
* * * * *
    15. Section 179.7 is added to subpart A to read as follows:


Sec. 179.7 Quality assurance program.

    (a) At a minimum, each tank car facility shall have a quality 
assurance program, approved by AAR, that--
    (1) Ensures the finished product conforms to the requirements of 
the applicable specification and regulations of this subchapter;
    (2) Has the means to detect any nonconformity in the manufacturing, 
repair, or testing of the tank car; and
    (3) Prevents non-conformities from recurring.
    (b) At a minimum, the quality assurance program must have the 
following elements
    (1) Statement of authority and responsibility for those persons in 
charge of the quality assurance program.
    (2) An organizational chart showing the interrelationship between 
managers, engineers, purchasing, construction, inspection, testing, and 
quality control personnel.
    (3) Procedures to ensure that the latest applicable drawings, 
design calculations, specifications, and instructions are used in 
manufacture, inspection, testing, and repair.
    (4) Procedures to ensure that the fabrication and construction 
materials received are properly identified and documented.
    (5) A description of the manufacturing, inspection, and testing 
program so that an inspector can determine specific inspection and test 
intervals.
    (6) Monitoring and control of processes and product characteristics 
during production.
    (7) Procedures for correction of imperfections.
    (8) Provisions indicating that the requirements of the AAR 
Specifications for Tank Cars, Specification M-1002, apply.
    (9) Qualification requirements of personnel performing ultrasonic, 
radiographic, dye penetrant, magnetic particle, or other non-
destructive inspections and tests.
    (10) Qualification requirements of personnel performing optically 
aided visual inspections (including fiber optic, borescope, and video-
image-scope systems). Under these requirements, the examiner must have 
the capability to consistently and repetitively find flaws under test 
conditions. Furthermore, the requirements must include visual acuity 
criteria where detectability (minimum size of a flaw that an examiner 
can find); resolution (minimum distance at which two flaws may be seen 
separately); and contrast sensitivity (minimum detectable thickness 
change (convolutions) over a surface area) further define the 
qualifications of the examiner.
    (11) Procedures for evaluating the inspection and test technique 
employed, including the accessibility of the area and the sensitivity 
of the inspection and test technique and minimum detectable crack 
length.
    (12) Procedures for the periodic calibration and measurement of 
inspection and test equipment.
    (13) A system for the maintenance of records, inspections, tests, 
and the interpretation of inspection and test results.
    (c) Each tank car facility shall ensure that only personnel 
qualified for each non-destructive inspection and test perform that 
particular operation.
    (d) Each tank car facility shall establish written procedures for 
their employees to ensure that the work performed on the tank car 
conforms to the specification and AAR approval for the tank car.
    (e) Each tank car facility shall train its employees in accordance 
with Subpart 

[[Page 49077]]
H of part 172 of this subchapter on the program and procedures 
specified in paragraph (b) of this section to ensure quality.
    (f) Date of conformance. After July 1, 1998, no tank car facility 
may manufacture, repair, inspect, or test tank cars subject to 
requirements of this subchapter, unless it is operating in conformance 
with a quality assurance program and written procedures required by 
paragraphs (a) and (b) of this section.
    16. Section 179.16 is added to subpart B to read as follows:


Sec. 179.16  Tank-head puncture-resistance systems.

    (a) Performance standard. When the regulations in this subchapter 
require a tank-head puncture-resistance system, the system shall be 
capable of sustaining, without any loss of lading, coupler-to-tank-head 
impacts at relative car speeds of 29 km/hour (18 mph) when:
    (1) The weight of the impact car is at least 119,295 kg (263,000 
pounds);
    (2) The impacted tank car is coupled to one or more backup cars 
that have a total weight of at least 217,724 kg (480,000 pounds) and 
the hand brake is applied on the last ``backup'' car; and
    (3) The impacted tank car is pressurized to at least 6.9 Bar (100 
psi).
    (b) Compliance with the requirements of paragraph (a) of this 
section shall be verified by full-scale testing according to Appendix A 
of this part or by installing full-head protection (shields) or full 
tank-head jackets on each end of the tank car conforming to the 
following
    (1) The tank-head puncture-resistance system must be at least 1.27 
cm (0.5 inch) thick, shaped to the contour of the tank head and made 
from steel having a tensile strength greater than 379.21 N/mm\2\ 
(55,000 psi).
    (2) The design and test requirements of the tank-head puncture-
resistance system must meet the impact test requirements of Section 5.3 
of the AAR Specifications for Tank Cars.
    (3) The workmanship must meet the requirements of Section C, Part 
II, Chapter 5 of the AAR Specifications for Design, Fabrication, and 
Construction of Freight Cars.
    17. Section 179.18 is added to subpart B to read as follows:


Sec. 179.18  Thermal protection systems.

    (a) Performance standard. When the regulations in this subchapter 
require thermal protection on a tank car, the tank car must have 
sufficient thermal resistance so that there will be no release of any 
lading within the tank car, except release through the safety relief 
valve, when subjected to:
    (1) A pool fire for 100 minutes; and
    (2) A torch fire for 30 minutes.
    (b) Thermal analysis. (1) Compliance with the requirements of 
paragraph (a) of this section shall be verified by modeling the fire 
effects on the entire surface of the tank car according to the 
procedures outlined in ``Temperatures, Pressures and Liquid Levels of 
Tank Cars Engulfed in Fires,'' DOT/FRA/OR&D-84/08.11, (1984), Federal 
Railroad Administration, Washington D.C. (available from National 
Technical Information Service, Springfield, VA 22161), or other 
procedure approved by the AAR Committee on Tank Cars. The analysis must 
also consider the fire effects on and the heat flux through tank 
discontinuities, protective housings, underframes, metal jackets, 
insulation, and thermal protection. A complete record of each analysis 
shall be made, retained and, upon request, made available for 
inspection and copying by an authorized representative of the 
Department.
    (2) When the analysis shows the thermal resistance of the tank car 
does not conform to paragraph (a) of this section, the thermal 
resistance of the tank car must be increased by using a system listed 
by the Department under paragraph (c) of this section or by testing an 
unlisted system and verifying it according to appendix B of this part.
    (c) Systems that no longer require test verification. The 
Department maintains a list of thermal protection systems that comply 
with the requirements of appendix B of this part and that no longer 
require test verification. Information necessary to equip tank cars 
with one of these systems is available in the Dockets Unit, Research 
and Special Programs Administration, 400 Seventh Street, SW., 
Washington, D.C. 20590-0001.
    18. Section 179.20 is added to subpart B to read as follows:


Sec. 179.20  Service equipment; protection systems.

    If an applicable tank car specification authorizes location of 
filling or discharge connections in the bottom shell, the connections 
must be designed, constructed, and protected according to paragraphs 
E9.00 and E10.00 of the AAR Specifications for Tank Cars, M-1002.
    19. Section 179.22 is added to subpart B to read as follows:


Sec. 179.22  Marking.

    In addition to any other marking requirement in this subchapter, 
the following marking requirements apply:
    (a) Each tank car must be marked according to the requirements in 
Appendix C of the AAR Specifications for Tank Cars.
    (b) Each tank car that is equipped with a tank-head puncture-
resistance system must have the letter ``S'' substituted for the letter 
``A'' in the specification marking.
    (c) Each tank car that is equipped with a tank-head puncture-
resistance system, a thermal protection system, and a metal jacket must 
have the letter ``J'' substituted for the letter ``A'' or ``S'' in the 
specification marking.
    (d) Each tank car that is equipped with a tank-head puncture-
resistance system, a thermal protection system, and no metal jacket 
must have the letter ``T'' substituted for the letter ``A'' or ``S'' in 
the specification marking.


Sec. 179.100-4  [Amended]

    20. In Sec. 179.100-4, in paragraph (a), the last sentence is 
amended by removing the phrase ``except that a protective coating is 
not required when foam-in-place insulation that adheres to the tank or 
jacket is applied''.


Secs. 179.100-21 and 179.100-23  [Removed]

    21. Sections 179.100-21 and 179.100-23 are removed.
    22. In Sec. 179.101-1, in paragraph (a), Note 4 following the table 
is revised to read as follows:


Sec. 179.101-1  Individual specification requirements.

    (a) * * *
    \4\ Tank cars not equipped with a thermal protection or an 
insulation system used for the transportation of a Class 2 
(compressed gas) material must have at least the upper two-thirds of 
the exterior of the tank, including manway nozzle and all 
appurtenances in contact with this area, finished with a reflective 
coat of white paint.
* * * * *


Sec. 179.103-1  [Amended]

    23. In Sec. 179.103-1, paragraph (c) is removed and reserved.
    24. In Sec. 179.103-2, paragraph (a) is revised to read as follows:


Sec. 179.103-2  Manway cover.

    (a) The manway cover must be an approved design.
* * * * *


Sec. 179.103-5  [Amended]

    25. In Sec. 179.103-5, paragraph (a)(1) is amended by removing the 
first two sentences.


Secs. 179.105, 179.105-1--179.105-8  [Removed]

    26. Sections 179.105, 179.105-1 through 179.105-8 are removed.
    27. In Sec. 179.200-4, in paragraph (a), the last sentence is 
revised to read as follows:

[[Page 49078]]



Sec. 179.200-4  Insulation.

    (a) * * * The exterior surface of a carbon steel tank and the 
inside surface of a carbon steel jacket must be given a protection 
coating.
* * * * *


Secs. 179.200-25 and 179.200-27  [Removed]

    28. Sections 179.200-25 and 179.200-27 are removed.


Secs. 179.203, 179.203-1--179.203-3  [Removed]

    29. Sections 179.203, 179.203-1 through 179.203-2 are removed.
    30. Appendixes A and B are added to Part 179 to read as follows:

Appendix A to Part 179--Procedures for Tank-Head Puncture-Resistance 
Test

    1. This test procedure is designed to verify the integrity of 
new or untried tank-head puncture-resistance systems and to test for 
system survivability after coupler-to-tank-head impacts at relative 
speeds of 29 km/hour (18 mph).
    2. Tank-head puncture-resistance test. A tank-head puncture-
resistance system must be tested under the following conditions:
    a. The ram car used must weigh at least 119,295 kg (263,000 
pounds), be equipped with a coupler, and duplicate the condition of 
a conventional draft sill including the draft yoke and draft gear. 
The coupler must protrude from the end of the ram car so that it is 
the leading location of perpendicular contact with the impacted test 
car.
    b. The impacted test car must be loaded with water at six 
percent outage with internal pressure of at least 6.9 Bar (100 psi) 
and coupled to one or more ``backup'' cars which have a total weight 
of 217,724 kg (480,000 pounds) with hand brakes applied on the last 
``backup'' car.
    c. At least two separate tests must be conducted with the 
coupler on the vertical centerline of the ram car. One test must be 
conducted with the coupler at a height of 53.3 cm (21 inches), plus-
or-minus 2.5 cm (1 inch), above the top of the sill; the other test 
must be conducted with the coupler height at 79 cm (31 inches), 
plus-or-minus 2.5 cm (1 inch), above the top of the sill. If the 
combined thickness of the tank head and any additional shielding 
material is less than the combined thickness on the vertical 
centerline of the car, a third test must be conducted with the 
coupler positioned so as to strike the thinnest point of the tank 
head.
    3. One of the following test conditions must be applied:

------------------------------------------------------------------------
                                 Minimum                                
 Minimum weight of attached    velocity of                              
   ram cars in kg (pounds)    impact in km/          Restrictions       
                                hour (mph)                              
------------------------------------------------------------------------
119,295 (263,000)...........  29 (18)......  One ram car only.          
155,582 (343,000)...........  25.5 (16)....  One ram car or one car plus
                                              one rigidly attached car. 
311,164 (686,000)...........  22.5 (14)....  One ram car plus one or    
                                              more rigidly attached     
                                              cars.                     
------------------------------------------------------------------------

    4. A test is successful if there is no visible leak from the 
standing tank car for at least one hour after impact.

Appendix B to Part 179--Procedures for Simulated Pool and Torch-Fire 
Testing

    1. This test procedure is designed to measure the thermal 
effects of new or untried thermal protection systems and to test for 
system survivability when exposed to a 100-minute pool fire and a 
30-minute torch fire.
    2. Simulated pool fire test. 
    a. A pool-fire environment must be simulated in the following 
manner:
    (1) The source of the simulated pool fire must be hydrocarbon 
fuel with a flame temperature of 871  deg.C (1,600  deg.F), plus-or-
minus 37.8  deg.C (100  deg.F), throughout the duration of the test.
    (2) A square bare plate with thermal properties equivalent to 
the material of construction of the tank car must be used. The plate 
dimensions must be not less than one foot by one foot by nominal 1.6 
cm (0.625 inch) thick. The bare plate must be instrumented with not 
less than nine thermocouples to record the thermal response of the 
bare plate. The thermocouples must be attached to the surface not 
exposed to the simulated pool fire and must be divided into nine 
equal squares with a thermocouple placed in the center of each 
square.
    (3) The pool-fire simulator must be constructed in a manner that 
results in total flame engulfment of the front surface of the bare 
plate. The apex of the flame must be directed at the center of the 
plate.
    (4) The bare plate holder must be constructed in such a manner 
that the only heat transfer to the back side of the bare plate is by 
heat conduction through the plate and not by other heat paths.
    (5) Before the bare plate is exposed to the simulated pool fire, 
none of the temperature recording devices may indicate a plate 
temperature in excess of 37.8  deg.C (100  deg.F) nor less than 0 
deg.C (32  deg.F).
    (6) A minimum of two thermocouple devices must indicate 427 
deg.C (800  deg.F) after 13 minutes, plus-or-minus one minute, of 
simulated pool-fire exposure.
    b. A thermal protection system must be tested in the simulated 
pool-fire environment described in paragraph 2a of this appendix in 
the following manner:
    (1) The thermal protection system must cover one side of a bare 
plate as described in paragraph 2a(2) of this appendix.
    (2) The non-protected side of the bare plate must be 
instrumented with not less than nine thermocouples placed as 
described in paragraph 2a(2) of this appendix to record the thermal 
response of the plate.
    (3) Before exposure to the pool-fire simulation, none of the 
thermocouples on the thermal protection system configuration may 
indicate a plate temperature in excess of 37.8  deg.C (100  deg.F) 
nor less than 0  deg.C (32  deg.F).
    (4) The entire surface of the thermal protection system must be 
exposed to the simulated pool fire.
    (5) A pool-fire simulation test must run for a minimum of 100 
minutes. The thermal protection system must retard the heat flow to 
the plate so that none of the thermocouples on the non-protected 
side of the plate indicate a plate temperature in excess of 427 
deg.C (800  deg.F).
    (6) A minimum of three consecutive successful simulation fire 
tests must be performed for each thermal protection system.
    3. Simulated torch fire test. 
    a. A torch-fire environment must be simulated in the following 
manner:
    (1) The source of the simulated torch must be a hydrocarbon fuel 
with a flame temperature of 1,204  deg.C (2,200  deg.F), plus-or-
minus 37.8  deg.C (100  deg.F), throughout the duration of the test. 
Furthermore, torch velocities must be 64.4 km/h  16 km/h 
(40 mph  10 mph) throughout the duration of the test.
    (2) A square bare plate with thermal properties equivalent to 
the material of construction of the tank car must be used. The plate 
dimensions must be at least four feet by four feet by nominal 1.6 cm 
(0.625 inch) thick. The bare plate must be instrumented with not 
less than nine thermocouples to record the thermal response of the 
plate. The thermocouples must be attached to the surface not exposed 
to the simulated torch and must be divided into nine equal squares 
with a thermocouple placed in the center of each square.
    (3) The bare plate holder must be constructed in such a manner 
that the only heat transfer to the back side of the plate is by heat 
conduction through the plate and not by other heat paths. The apex 
of the flame must be directed at the center of the plate.
    (4) Before exposure to the simulated torch, none of the 
temperature recording devices may indicate a plate temperature in 
excess of 37.8  deg.C (100  deg.F) or less than 0  deg.C (32 
deg.F).
    (5) A minimum of two thermocouples must indicate 427  deg.C (800 
 deg.F) in four minutes, plus-or-minus 30 seconds, of torch 
simulation exposure.
    b. A thermal protection system must be tested in the simulated 
torch-fire environment described in paragraph 3a of this appendix in 
the following manner:
    (1) The thermal protection system must cover one side of the 
bare plate identical to that used to simulate a torch fire under 
paragraph 3a(2) of this appendix.
    (2) The back of the bare plate must be instrumented with not 
less than nine thermocouples placed as described in 

[[Page 49079]]
paragraph 3a(2) of this appendix to record the thermal response of the 
material.
    (3) Before exposure to the simulated torch, none of the 
thermocouples on the back side of the thermal protection system 
configuration may indicate a plate temperature in excess of 37.8 
deg.C (100  deg.F) nor less than 0  deg.C (32  deg.F).
    (4) The entire outside surface of the thermal protection system 
must be exposed to the simulated torch-fire environment.
    (5) A torch-simulation test must be run for a minimum of 30 
minutes. The thermal protection system must retard the heat flow to 
the plate so that none of the thermocouples on the backside of the 
bare plate indicate a plate temperature in excess of 427  deg.C (800 
 deg.F).
    (6) A minimum of two consecutive successful torch-simulation 
tests must be performed for each thermal protection system.
PART 180--CONTINUING QUALIFICATION AND MAINTENANCE OF PACKAGINGS
    31. The authority citation for part 180 continues to read as 
follows:

    Authority: 49 U.S.C. 5101-5127; 49 CFR 1.53.

    32. A new Subpart F is added to part 180 to read as follows:
Subpart F--Qualification and Maintenance of Tank Cars
Sec.
180.501  Applicability.
180.503  Definitions.
180.505  Quality assurance program.
180.507  Qualification of tank cars.
180.509  Requirements for inspection and test of specification tank 
cars.
180.511  Acceptable results of inspections and tests.
180.513  Repairs, alterations, conversions, and modifications.
180.515  Markings.
180.517  Reporting and record retention requirements.
180.519  Periodic retest and inspection of tank cars other than 
single-unit tank car tanks.
Subpart F--Qualification and Maintenance of Tank Cars
Sec. 180.501  Applicability.

    (a) This subpart prescribes requirements, in addition to those 
contained in parts 107, 171, 172, 173, and 179 of this subchapter, 
applicable to any person who manufactures, fabricates, marks, 
maintains, repairs, inspects, or services tank cars to ensure that the 
tank cars are in proper condition for transportation.
    (b) Any person who performs a function prescribed in this part 
shall perform that function in accordance with this part.
Sec. 180.503  Definitions.

    The definitions contained in Secs. 171.8 and 179.2 of this 
subchapter apply.


Sec. 180.505  Quality assurance program.

    The quality assurance program requirements of Sec. 179.7 of this 
subchapter apply.


Sec. 180.507  Qualification of tank cars.

    (a) Each tank car marked as meeting a ``DOT'' specification or any 
other tank car used for the transportation of a hazardous material must 
meet the requirements of this subchapter or the applicable 
specification to which the tank was constructed.
    (b) Tank car specifications no longer authorized for construction. 
(1) Tank cars prescribed in the following table are authorized for 
service provided they conform to all applicable safety requirements of 
this subchapter:

------------------------------------------------------------------------
Specification prescribed in the                                         
      current regulations         Other specifications permitted   Notes
------------------------------------------------------------------------
105A200W.......................  105A100W.......................       1
105A200ALW.....................  105A100ALW.....................       1
105A300W.......................  ICC-105, 105A300...............        
105A400W.......................  105A400........................        
105A500W.......................  105A500........................        
105A600W.......................  105A600........................        
106A500X.......................  ICC-27, BE-27, 106A500.........        
106A800X.......................  106A800........................        
107A * * * *...................  ...............................       2
------------------------------------------------------------------------
Note 1: Tanks built as Specification DOT 105A100W or DOT 105A100ALW may 
  be altered and converted to DOT 105A200W and DOT 105A200ALW,          
  respectively.                                                         
Note 2: The test pressures of tanks built in the United States between  
  January 1, 1941 and December 31, 1955, may be increased to conform to 
  Specification 107A. Original and revised test pressure markings must  
  be indicated and may be shown on the tank or on a plate attached to   
  the bulkhead of the car. Tanks built before 1941 are not authorized.  

    (2) For each tank car conforming to and used under an exemption 
issued before October 1, 1984, which authorized the transportation of a 
cryogenic liquid in a tank car, the owner or operator shall remove the 
exemption number stenciled on the tank car and stamp the tank car with 
the appropriate Class DOT-113 specification followed by the applicable 
exemption number. For example: DOT-113D60W-E * * * * (asterisks to be 
replaced by the exemption number). The owner or operator marking a tank 
car in this manner shall retain on file a copy of the last exemption in 
effect during the period the tank car is in service. No person may 
modify a tank car marked under this paragraph unless the modification 
is in compliance with an applicable requirement or provision of this 
subchapter.
    (3) Specification DOT-113A175W, DOT-113C60W, DOT-113D60W, and DOT-
113D120W tank cars may continue in use, but new construction is not 
authorized.
    (4) Class DOT 105A and 105S tank cars used to transport hydrogen 
chloride, refrigerated liquid under the terms of DOT-E 3992 may 
continue in service, but new construction is not authorized.


Sec. 180.509  Requirements for inspection and test of specification 
tank cars.

    (a) General. (1) Each tank car facility shall evaluate a tank car 
according to the requirements specified in Sec. 180.511.
    (2) Each tank car that successfully passes a periodic inspection 
and test must be marked as prescribed in Sec. 180.515.
    (3) A written report as specified in Sec. 180.517(b) must be 
prepared for each tank car that is inspected and tested under this 
section.
    (b) Conditions requiring inspection and test of tank cars. Without 
regard to any other periodic inspection and test requirement, a tank 
car must have an inspection and test according to this section if:
    (1) The tank car shows evidence of abrasion, corrosion, cracks, 
dents, distortions, defects in welds, or any other condition that makes 
the tank car unsafe for transportation.
    (2) The tank car was in an accident and damaged to an extent that 
may adversely affect its capability to retain its contents.
    (3) The tank bears evidence of damage caused by fire.
    (4) The Associate Administrator for Safety, FRA, requires it based 
on the existence of probable cause that a tank car or a class or design 
of tank cars may be in an unsafe operating condition.
    (c) Frequency of inspection and tests. Each tank car shall have an 
inspection and test according to the requirements of this paragraph.
    (1) For Class 107 tank cars and tank cars of riveted construction, 
the tank car must have a hydrostatic pressure test and visual 
inspection conforming to the requirements in effect prior to July 1, 
1996, for the tank specification.
    (2) For Class DOT 113 tank cars, see Sec. 173.319(e) of this 
subchapter.
    (3) For fusion welded tank cars, each tank car must have an 
inspection and test in accordance with paragraphs (d) through (k) of 
this section.
    (i) For cars transporting materials not corrosive to the tank, 
every 10 years for the tank and service equipment (i.e., filling and 
discharge, venting, safety, heating, and measuring devices).
    (ii) For non-lined or non-coated tank cars transporting materials 
corrosive to the tank, an interval based on the following formula, but 
in no case shall 

[[Page 49080]]
the interval exceed 10 years for the tank and 5 years for service 
equipment:

                                                                        
                                      t1-t2                             
                              i =  ----------                           
                                        r                               
                                                                        

where:
i  is the inspection and test interval.
t1  is the actual thickness.
t2  is the allowable minimum thickness under paragraph (g) of this 
section.
r  is the corrosion rate per year.

    (iii) For lined or coated tank cars transporting a material 
corrosive to the tank, every 10 years for the tank, 5 years for the 
service equipment, and when a lining or coating is applied to protect 
the tank shell from the lading, an interval based on the owner's 
determination for the lining or coating, but not greater than every 10 
years.
    (A) When a lining or coating is applied to protect the tank shell 
from the lading, each owner of a lining or coating shall determine the 
periodic inspection interval and test technique for the lining or 
coating. The owner must maintain all supporting documentation used to 
make such a determination, such as the lining or coating manufacturer's 
recommended inspection interval and test technique, at the owner's 
principal place of business.
    (B) The supporting documentation used to make such inspection and 
test interval determinations and technique must be made available to 
FRA upon request.
    (d) Visual inspection. At a minimum, each tank car facility must 
visually inspect the tank externally and internally as follows:
    (1) An internal inspection of the tank shell and heads for 
abrasion, corrosion, cracks, dents, distortions, defects in welds, or 
any other condition that makes the tank car unsafe for transportation, 
and except in the areas where insulation or a thermal protection system 
precludes it, an external inspection of the tank shell and heads for 
abrasion, corrosion, cracks, dents, distortions, defects in welds, or 
any other condition that makes the tank car unsafe for transportation;
    (2) An inspection of the piping, valves, fittings, and gaskets for 
indications of corrosion and other conditions that make the tank car 
unsafe for transportation;
    (3) An inspection for missing or loose bolts, nuts, or elements 
that make the tank car unsafe for transportation;
    (4) An inspection of all closures on the tank car for proper 
securement in a tool tight condition and an inspection of the 
protective housings for proper securement;
    (5) An inspection of excess flow valves having threaded seats for 
tightness; and
    (6) An inspection of the required markings on the tank car for 
legibility.
    (e) Structural integrity inspections and tests. At a minimum, each 
tank car facility shall inspect the tank car for structural integrity 
as specified in this section. The structural integrity inspection and 
test shall include all transverse fillet welds greater than 0.64 cm 
(0.25 inch) within 121.92 cm (4 feet) of the bottom longitudinal center 
line; the termination of longitudinal fillet welds greater than 0.64 cm 
(0.25 inch) within 121.92 cm (4 feet) of the bottom longitudinal center 
line; and all tank shell butt welds within 60.96 cm (2 feet) of the 
bottom longitudinal center line by one or more of the following 
inspection and test methods to determine that the welds are in proper 
condition:
    (1) Dye penetrant test;
    (2) Radiography test;
    (3) Magnetic particle test;
    (4) Ultrasonic test; or
    (5) Optically-aided visual inspection (e.g., magnifiers, 
fiberscopes, borescopes, and machine vision technology).
    (f) Thickness tests. (1) Each tank car facility shall measure the 
thickness of the tank car shell, heads, sumps, domes, and nozzles on 
each tank car by using a device capable of accurately measuring the 
thickness to within 0.05 mm (0.002 inch).
    (2) After repairs, alterations, conversions or modifications of a 
tank car that result in a reduction to the tank car shell thickness, 
the tank car facility shall measure the thickness of the tank car shell 
in the area of reduced shell thickness to ensure that the shell 
thickness conforms to paragraph (g) of this section.
    (g) Service life shell thickness allowance. (1) A tank car found 
with a shell thickness below the required minimum thickness after 
forming for its specification, as stated in part 179 of this 
subchapter, may continue in service if:
     (i) Construction of the tank car shell and heads is from carbon 
steel, stainless steel, aluminum, nickel, or manganese-molybdenum 
steel; and
     (ii) Any reduction in thickness of the tank shell or head is not 
more than that provided in the following table:

                                      Allowable Shell Thickness Reductions                                      
----------------------------------------------------------------------------------------------------------------
                     Class DOT 103, 104, 111, and 115 tank       Class DOT 105, 109, 112, and 114 tank cars     
                                     cars                  -----------------------------------------------------
    Damage type    ----------------------------------------                                                     
                         Top shell         Bottom shell         Top shell                 Bottom shell          
----------------------------------------------------------------------------------------------------------------
Corrosion.........  3.17 mm (0.125      1.58 mm (0.063      0.79 mm (0.031     0.79 mm (0.031 inch).            
                     inch).              inch).              inch).                                             
Corrosion and       3.17 mm (0.125      1.58 mm (0.063      0.79 mm (0.031     0.79 mm (0.031 inch).            
 mechanical.         inch).              inch).              inch).                                             
Corrosion, local..  4.76 mm (\3/16\     3.17 mm (0.125      1.58 mm (0.063     1.58 mm (0.063 inch).            
                     inch).              inch).              inch).                                             
Mechanical, local.  3.17 mm (0.125      1.58 mm (0.063      1.58 mm (0.063     1.58 mm (0.063 inch).            
                     inch).              inch).              inch).                                             
Corrosion and       4.76 mm (\3/16\     3.17 mm (0.125      1.58 mm (0.063     1.58 mm (0.063 inch).            
 mechanical, local.  inch).              inch).              inch).                                             
----------------------------------------------------------------------------------------------------------------
Notes:                                                                                                          
1. The perimeter for a local reduction may not exceed a 60.96 cm (24 inch) perimeter. Local reductions in the   
  top shell must be separated from other reductions in the top shell by at least 40.64 cm (16 inches). The      
  cumulative perimeter for local reductions in the bottom shell may not exceed 182.88 cm (72 inches).           
2. Any reduction in the tank car shell may not affect the structural strength of the tank car so that the tank  
  car shell no longer conforms to Section 6.2 of the AAR Specifications for Tank Cars.                          
3. Any reduction applies only to the outer shell for Class DOT 115 tank cars.                                   
4. For Class DOT 103 and 104 tank cars, the inside diameter may not exceed 243.84 cm (96 inches).               

     (h) Safety system inspections. At a minimum, each tank car 
facility must inspect:
    (1) Tank car thermal protection systems, tank head puncture 
resistance systems, coupler vertical restraint systems, and systems 
used to protect discontinuities (i.e., skid protection and protective 
housings) to ensure their integrity. 

[[Page 49081]]

     (2) Reclosing pressure relief devices by:
    (i) Removing the safety relief device from the tank car for 
inspection; and
    (ii) Testing the safety relief device with air or another gas to 
ensure that it conforms to the start-to-discharge pressure for the 
specification or hazardous material in this subchapter.
    (i) Lining and coating inspection and test. When this subchapter 
requires a lining or coating, at a minimum, each tank car facility must 
inspect the lining or coating installed on the tank car according to 
the inspection interval and test technique established by the owner of 
the lining or coating in accordance with paragraph (c)(3)(iii) of this 
section.
    (j) Leakage pressure test. (1) At a minimum, each tank car facility 
shall perform a leakage pressure test on the tank fittings and 
appurtenances. The leakage pressure test must include product piping 
with all valves and accessories in place and operative, except that 
during the pressure test the tank car facility shall remove or render 
inoperative any venting devices set to discharge at less than the test 
pressure. Test pressure must be maintained for at least 5 minutes. 
Leakage test pressure may not be less than 2.1 Bar (30 psig) for tank 
cars having a test pressure less than or equal to 13.8 Bar (200 psig), 
or 3.4 Bar (50 psig) for tank cars having a tank test pressure greater 
than 13.8 Bar (200 psig).
    (2) Interior heater systems must be tested hydrostatically at 13.87 
Bar (200 psi) and must show no signs of leakage.
    (k) Alternative inspection and test procedures. In lieu of the 
other requirements of this section, a person may use an alternative 
inspection and test procedure or interval based on a damage-tolerance 
fatigue evaluation (that includes a determination of the probable 
locations and modes of damage due to fatigue, corrosion, or accidental 
damage), when the evaluation is examined by the Association of American 
Railroads Tank Car Committee and approved by the Associate 
Administrator for Safety, FRA.
    (l) Inspection and test compliance date for tank cars with metal 
jackets or thermal protection systems. (1) After July 1, 2000, each 
tank car with a metal jacket or with a thermal protection system shall 
have an inspection and test conforming to this section no later than 
the date the tank car requires a periodic hydrostatic pressure test 
(i.e., the marked due date on the tank car for the hydrostatic test).
    (2) After July 1, 1998, each tank car without a metal jacket shall 
have an inspection and test conforming to this section no later than 
the date the tank car requires a periodic hydrostatic pressure test 
(i.e., the marked due date on the tank car for the hydrostatic test).
    (3) For tank cars on a 20-year periodic hydrostatic pressure test 
interval (i.e., Class DOT 103W, 104W, 111A60W1, 111A100W1, and 
111A100W3 tank cars), the next inspection and test date is the midpoint 
between the compliance date in paragraph (l)(1) or (2) of this section 
and the remaining years until the tank would have had a hydrostatic 
pressure test.


Sec. 180.511  Acceptable results of inspections and tests.

    Provided it conforms with other applicable requirements of this 
subchapter, a tank car is qualified for use if it successfully passes 
the following inspections and tests conducted in accordance with this 
subpart:
    (a) Visual inspection. A tank car successfully passes the visual 
inspection when the inspection shows no structural defect that may 
cause leakage from or failure of the tank before the next inspection 
and test interval.
    (b) Structural integrity inspection and test. A tank car 
successfully passes the structural integrity inspection and test when 
it shows no structural defect that may initiate cracks or propagate 
cracks and cause failure of the tank before the next inspection and 
test interval.
    (c) Service life shell thickness. A tank car successfully passes 
the service life shell thickness inspection when the tank shell and 
heads show no thickness reduction below that allowed in 
Sec. 180.509(g).
    (d) Safety system inspection. A tank car successfully passes the 
safety system inspection when each thermal protection system, tank head 
puncture resistance system, coupler vertical restraint system, and 
system used to protect discontinuities (e.g., breakage grooves on 
bottom outlets and protective housings) on the tank car conform to this 
subchapter.
    (e) Lining and coating inspection. A tank car successfully passes 
the lining and coating inspection and test when the lining or coating 
shows no evidence of holes or degraded areas.
    (f) Leakage pressure test. A tank car successfully passes the 
leakage pressure test when all product piping, fittings and closures 
show no indication of leakage.
    (g) Hydrostatic test. A Class 107 tank car or a riveted tank car 
successfully passes the hydrostatic test when it shows no leakage, 
distortion, excessive permanent expansion, or other evidence of 
weakness that might render the tank car unsafe for transportation 
service.


Sec. 180.513  Repairs, alterations, conversions, and modifications.

    (a) In order to repair tank cars, the tank car facility must comply 
with the requirements of Appendix R of the AAR Specifications for Tank 
Cars.
    (b) Unless the exterior tank car shell or interior tank car jacket 
has a protective coating, after a repair that requires the complete 
removal of the tank car jacket, the exterior tank car shell and the 
interior tank car jacket must have a protective coating applied to 
prevent the deterioration of the tank shell and tank jacket.


Sec. 180.515  Markings.

    (a) When a tank car passes the required inspection and test with 
acceptable results, the tank car facility shall mark the date of the 
inspection and test and the due date of the next inspection and test on 
the tank car in accordance with paragraph (b) of this section. When a 
tank car facility performs multiple inspection and test at the same 
time, one date may be used to satisfy the requirements of this section. 
One date also may be shown when multiple inspection and test have the 
same due date.
    (b) The tank car facility must comply with the marking requirements 
of Appendix C of the AAR Specifications for Tank Cars.
    (c) Converted tank cars must have the new specification and 
conversion date permanently marked in letters and figures at least 0.95 
cm (0.375 inch) high on the outside of the manway nozzle or the edge of 
the manway nozzle flange on the left side of the car. The marking may 
have the last numeral of the specification number omitted (e.g., ``DOT 
111A100W'' instead of ``DOT 111A100W1'').
    (d) When pressure tested within six months of installation and 
protected from deterioration, the test date marking of a safety relief 
device is the installation date on the tank car.


Sec. 180.517  Reporting and record retention requirements.

    (a) Certification and representation. Each owner of a specification 
tank car shall retain the certificate of construction (AAR Form 4-2) 
and related papers certifying that the manufacture of the specification 
tank car identified in the documents is in accordance with the 
applicable specification. The owner shall retain the documents 
throughout the period of ownership of the specification tank car and 
for one year thereafter. Upon a 

[[Page 49082]]
change of ownership, the requirements of Section 1.3.15 of the AAR 
Specifications for Tank Cars apply.
    (b) Inspection and test reporting. Each tank car that is inspected 
as specified in Sec. 180.509 must have a written report, in English, 
prepared according to this paragraph. The owner must retain a copy of 
the inspection and test reports until successfully completing the next 
inspection and test of the same type. The inspection and test report 
must include the following:
    (1) Type of inspection and test performed (a checklist is 
acceptable);
    (2) The results of each inspection and test performed;
    (3) Owner's reporting mark;
    (4) DOT Specification;
    (5) Inspection and test date (month and year);
    (6) Location and description of defects found and method used to 
repair each defect;
    (7) The name and address of the tank car facility and the signature 
of inspector.


Sec. 180.519  Periodic retest and inspection of tank cars other than 
single-unit tank car tanks.

    (a) General. Unless otherwise provided in this subpart, tanks 
designed to be removed from cars for filling and emptying and tanks 
built to a Class DOT 107A specification and their safety relief devices 
must be retested periodically as specified in Retest Table 1 of 
paragraph (b)(5) of this section. Retests may be made at any time 
during the calendar year the retest falls due.
    (b) Pressure test. (1) Each tank, except as provided in paragraph 
(b)(8) of this section, must be subjected to the specified hydrostatic 
pressure and its permanent expansion determined. Pressure must be 
maintained for 30 seconds and far as long as necessary to secure 
complete expansion of the tank. Before testing, the pressure gauge must 
be shown to be accurate within 1 percent at test measure. The expansion 
gauge must be shown to be accurate, at test pressure, to within 1 
percent. Expansion must be recorded in cubic centimeters. Permanent 
volumetric expansion may not exceed 10 percent of total volumetric 
expansion at test pressure and the tank must not leak or show evidence 
of distress.
    (2) Each tank, except tanks built to specification DOT 107A, must 
also be subjected to interior air pressure test of at least 100 psi 
under conditions favorable to detection of any leakage. No leaks may 
appear.
    (3) Safety relief valves must be retested by air or gas, must start 
to discharge at or below the prescribed pressure and must be vapor 
tight at or above the prescribed pressure.
    (4) Frangible discs and fusible plugs must be removed from the tank 
and visually inspected.
    (5) Tanks must be retested as specified in Retest Table 1 of this 
paragraph (b)(5), and before returning to service after repairs 
involving welding or heat treatment:

                                                 Retest Table 1                                                 
----------------------------------------------------------------------------------------------------------------
                                     Retest interval--years   Minimum Retest pressure--    Safety relief valve  
                                   --------------------------          p.s.i.               pressure--p.s.i.    
                                                             ---------------------------------------------------
           Specification                            Safety        Tank                                          
                                        Tank        relief    hydrostatic    Tank air    Start-to-   Vapor tight
                                                   devicesd    expansionc      test      discharge              
----------------------------------------------------------------------------------------------------------------
DOT 27............................            5            2          500          100          375          300
106A500...........................            5            2          500          100          375          300
106A500X..........................            5            2          500          100          375          300
106A800...........................            5            2          800          100          600          480
106A800X..........................            5            2          800          100          600          480
106A800NCI........................            5            2          800          100          600          480
107A * * * *......................           d5           a2          (b)         None         None         None
110A500-W.........................            5            2          500          100          375          300
110A600-W.........................            5            2          600          100          500          360
110A800-W.........................            5            2          800          100          600          480
110A1000-W........................            5            2        1,000          100          750          600
BE-275............................            5            2          500          100          375          300
----------------------------------------------------------------------------------------------------------------
Notes:                                                                                                          
aIf DOT 107A * * * * tanks are used for transportation of flammable gases, one frangible disc from each car must
  be burst at the interval prescribed. The sample disc must burst at a pressure not exceeding the marked test   
  pressure of the tank and not less than 70 percent of the marked test pressure. If the sample disc does not    
  burst within the prescribed limits, all discs on the car must be replaced.                                    
bThe hydrostatic expansion test pressure must at least equal the marked test pressure.                          
cSee Sec. 180.519(b)(1).                                                                                        
dSafety relief valves of the spring-loaded type on tanks used exclusively for fluorinated hydrocarbons and      
  mixtures thereof which are free from corroding components may be retested every 5 years.                      

    (6) The month and year of test, followed by a ``V'' if visually 
inspected as described in paragraph (d)(8) of this section, must be 
plainly and permanently stamped into the metal of one head or chime of 
each tank with successful test results; for example, 1-60 for January 
1960. On DOT 107A**** tanks, the date must be stamped into the metal of 
the marked end, except that if all tanks mounted on a car have been 
tested, the date may be stamped into the metal of a plate permanently 
applied to the bulkhead on the ``A'' end of the car. Dates of previous 
tests and all prescribed markings must be kept legible.
    (c) Visual inspection. Tanks of Class DOT 106A and DOT 110A-Z 
specifications (Secs. 179.300, 179.301, 179.302 of this subchapter) 
used exclusively for transporting fluorinated hydrocarbons and mixtures 
thereof, and that are free from corroding components, may be given a 
periodic complete internal and external visual inspection in place of 
the periodic hydrostatic retest. Visual inspections shall be made only 
by competent persons. The tank must be accepted or rejected in 
accordance with the criteria in CGA Pamphlet C-6.
    (d) Written records. The results of the pressure test and visual 
inspection must be recorded on a suitable data sheet. Completed copies 
of these reports must be retained by the owner and by the person 
performing the pressure test and visual inspection as long as the tank 
is in service. The information to be recorded and checked on these data 


[[Page 49083]]
sheets are: Date of test and inspection; DOT specification number; tank 
identification (registered symbol and serial number, date of 
manufacture and ownership symbol); type of protective coating (painted, 
etc., and statement as to need for refinishing or recoating); 
conditions checked (leakage, corrosion, gouges, dents or digs, broken 
or damaged chime or protective ring, fire, fire damage, internal 
condition); test pressure; results of tests; and disposition of tank 
(returned to service, returned to manufacturer for repair, or 
scrapped); and identification of the person conducting the retest or 
inspection.

    Issued in Washington, DC, on September 7, 1995 under authority 
delegated in 49 CFR Part 1.
D.K. Sharma,
Administrator.
[FR Doc. 95-22771 Filed 9-20-95; 8:45 am]
BILLING CODE 4910-60-P