[Title 49 CFR E]
[Code of Federal Regulations (annual edition) - October 1, 2006 Edition]
[Title 49 - TRANSPORTATION]
[Subtitle B - Other Regulations Relating to Transportation (Continued)]
[Chapter II - FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF]
[Part 236 - RULES, STANDARDS, AND INSTRUCTIONS GOVERNING THE]
[Subpart E - Automatic Train Stop, Train Control and Cab Signal Systems]
[From the U.S. Government Publishing Office]


49TRANSPORTATION42006-10-012006-10-01falseAutomatic Train Stop, Train Control and Cab Signal SystemsESubpart ETRANSPORTATIONOther Regulations Relating to Transportation (Continued)FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OFRULES, STANDARDS, AND INSTRUCTIONS GOVERNING THE
  Subpart E_Automatic Train Stop, Train Control and Cab Signal Systems

                                Standards



Sec. 236.501  Forestalling device and speed control.

    (a) An automatic train stop system may include a device by means of 
which the automatic application of the brakes can be forestalled.
    (b) Automatic train control system shall include one or more of the 
following features:
    (1) Low-speed restriction, requiring the train to proceed under slow 
speed after it has either been stopped by an automatic application of 
the brakes, or under control of the engineman, its speed has been 
reduced to slow speed, until the apparatus is automatically restored to 
normal because the condition which caused the restriction no longer 
affects the movement of the train.
    (2) Medium-speed restriction, requiring the train to proceed under 
medium speed after passing a signal displaying an approach aspect or 
when approaching a signal requiring a stop, or a stop indication point, 
in order to prevent an automatic application of the brakes.

    Note: Relief from the requirements of paragraphs (b) (1) and (2) of 
this section will be granted, insofar as speed limits fixed by 
definitions of Slow and Medium speeds are concerned, upon an adequate 
showing by an individual carrier where automatic train control systems 
now in service enforce speed restrictions higher than those required by 
definitions in Sec. Sec. 236.700 to 236.838 inclusive.

    (3) Maximum-speed restriction, effecting an automatic brake 
application whenever the predetermined maximum speed limit is exceeded.



Sec. 236.502  Automatic brake application, initiation by restrictive 

block conditions stopping distance in advance.

    An automatic train-stop or train-control system shall operate to 
initiate an automatic brake application at least stopping distance from 
the entrance to a block, wherein any condition described in Sec. 
236.205 obtains, and at each main track signal requiring a reduction in 
speed.



Sec. 236.503  Automatic brake application; initiation when 

predetermined rate of speed exceeded.

    An automatic train control system shall operate to initiate an 
automatic brake application when the speed of the train exceeds the 
predetermined rate as required by the setting of the speed control 
mechanism.



Sec. 236.504  Operation interconnected with automatic block-signal 

system.

    (a) A continuous inductive automatic train stop or train control 
system shall operate in connection with an automatic block signal system 
and shall be

[[Page 619]]

so interconnected with the signal system as to perform its intended 
function in event of failure of the engineer to acknowledge or obey a 
restrictive wayside signal or a more restrictive cab signal.
    (b) An intermittent inductive automatic train stop system shall 
operate in connection with an automatic block signal system and shall be 
so interconnected with the signal system that the failure of the 
engineer to acknowledge a restrictive wayside signal will cause the 
intermittent inductive automatic train stop system to perform its 
intended function.

[49 FR 3386, Jan. 26, 1984]



Sec. 236.505  Proper operative relation between parts along roadway 

and parts on locomotive.

    Proper operative relation between the parts along the roadway and 
the parts on the locomotive shall obtain under all conditions of speed, 
weather, wear, oscillation, and shock.



Sec. 236.506  Release of brakes after automatic application.

    The automatic train stop or train control apparatus shall prevent 
release of the brakes after automatic application until a reset device 
has been operated, or the speed of the train has been reduced to a 
predetermined rate, or the condition that caused the brake application 
no longer affects the movement of the train. If reset device is used it 
shall be arranged so that the brakes cannot be released until the train 
has been stopped, or it shall be located so that it cannot be operated 
by engineman without leaving his accustomed position in the cab.



Sec. 236.507  Brake application; full service.

    The automatic train stop or train control apparatus shall, when 
operated, cause a full service application of the brakes.



Sec. 236.508  Interference with application of brakes by means of 
brake valve.

    The automatic train stop, train control, or cab signal apparatus 
shall be so arranged as not to interfere with the application of the 
brakes by means of the brake valve and not to impair the efficiency of 
the brake system.

[49 FR 3386, Jan. 26, 1984]



Sec. 236.509  Two or more locomotives coupled.

    The automatic train stop, train control or cab signal apparatus 
shall be arranged so that when two or more locomotives are coupled, or a 
pushing or helping locomotive is used, it can be made operative only on 
the locomotive from which the brakes are controlled.



Sec. 236.510  [Reserved]



Sec. 236.511  Cab signals controlled in accordance with block 

conditions stopping distance in advance.

    The automatic cab signal system shall be arranged so that cab 
signals will be continuously controlled in accordance with conditions 
described in Sec. 236.205 that obtain at least stopping distance in 
advance.



Sec. 236.512  Cab signal indication when locomotive enters block where 

restrictive conditions obtain.

    The automatic cab signal system shall be arranged so that when a 
locomotive enters or is within a block, wherein any condition described 
in Sec. 236.205 obtains, the cab signals shall indicate ``Proceed at 
Restricted Speed.''



Sec. 236.513  Audible indicator.

    (a) The automatic cab signal system shall be so arranged that when 
the cab signal changes to display a more restrictive aspect, an audible 
indicator will sound continuously until silenced by manual operation of 
an acknowledging device.
    (b) The audible cab indicator of automatic cab signal, automatic 
train stop, or automatic train control system shall have a distinctive 
sound and be clearly audible throughout the cab under all operating 
conditions.

[49 FR 3386, Jan. 26, 1984]

[[Page 620]]



Sec. 236.514  Interconnection of cab signal system with roadway signal 

system.

    The automatic cab signal system shall be interconnected with the 
roadway-signal system so that the cab signal indication will not 
authorize operation of the train at a speed higher than that authorized 
by the indication of the roadway signal that governed the movement of a 
train into a block except when conditions affecting movement of trains 
in the block change after the train passes the signal.



Sec. 236.515  Visibility of cab signals.

    The cab signals shall be plainly visible to member or members of the 
locomotive crew from their stations in the cab.

[49 FR 3386, Jan. 26, 1984]



Sec. 236.516  Power supply.

    Automatic cab signal, train stop, or train control device hereafter 
installed shall operate from a separate or isolated power supply.

[49 FR 3386, Jan. 26, 1984]

                     Rules and Instructions; Roadway



Sec. 236.526  Roadway element not functioning properly.

    When a roadway element except track circuit of automatic train stop, 
train control or cab signal system is not functioning as intended, the 
signal associated with such roadway element shall be caused manually to 
display its most restrictive aspect until such element has been restored 
to normal operative condition.



Sec. 236.527  Roadway element insulation resistance.

    Insulation resistance between roadway inductor and ground shall be 
maintained at not less than 10,000 ohms.

[49 FR 3386, Jan. 26, 1984]



Sec. 236.528  Restrictive condition resulting from open hand-operated 

switch; requirement.

    When a facing point hand-operated switch is open one-fourth inch or 
more, a trailing point hand-operated switch three-eighths inch or more, 
or hand-operated switch is not locked where facing point lock with 
circuit controller is used, the resultant restrictive condition of an 
automatic train stop or train control device of the continuous type or 
the resultant restrictive cab signal indication of an automatic cab 
signal device on an approaching locomotive shall be maintained to within 
300 feet of the points of the switch.



Sec. 236.529  Roadway element inductor; height and distance from rail.

    Inductor of the inert roadway element type shall be maintained with 
the inductor pole faces at a height above the plane of the tops of the 
rails, and with its inner edge at a hmrizontal distance from the gage 
side of the nearest running rail, in accordance with specifications of 
the carrier.

[49 FR 3386, Jan. 26, 1984]



Sec. 236.530  [Reserved]



Sec. 236.531  Trip arm; height and distance from rail.

    Trip arm of automatic train stop device when in the stop position 
shall be maintained at a height above the plane of the tops of the 
rails, and at a horizontal distance from its center line to gage side of 
the nearest running rail, in accordance with specifications of the 
carrier.

[49 FR 3386, Jan. 26, 1984]



Sec. 236.532  Strap iron inductor; use restricted.

    No railroad shall use strap iron inductor or other roadway element 
with characteristics differing from its standard type on track where 
speed higher than restricted speed is permitted.

[49 FR 3386, Jan. 26, 1984]



Sec. 236.533  [Reserved]



Sec. 236.534  Entrance to equipped territory; requirements.

    Where trains are not required to stop at the entrance to equipped 
territory, except when leaving yards and stations and speed until 
entering equipped territory does not exceed restricted speed, the 
automatic train stop, train control, or cab signal device shall be 
operative

[[Page 621]]

at least stopping distance from the entrance to such territory except 
where the approach thereto is governed by automatic approach signal.

                   Rules and Instructions; Locomotives



Sec. 236.551  Power supply voltage; requirement.

    The voltage of power supply shall be maintained within 10 percent of 
rated voltage.



Sec. 236.552  Insulation resistance; requirement.

    When periodic test prescribed in Sec. 236.588 is performed, 
insulation resistance between wiring and ground of continuous inductive 
automatic cab signal system, automatic train control system, or 
automatic train stop system shall be not less than one megohm, and that 
of an intermittent inductive automatic train stop system, not less than 
250,000 ohms. Insulation resistance values between periodic tests shall 
be not less than 250,000 ohms for a continuous inductive automatic cab 
signal system, automatic train control system, or automatic train stop 
system, and 20,000 ohms for an intermittent inductive automatic train 
stop system.

[49 FR 3387, Jan. 26, 1984]



Sec. 236.553  Seal, where required.

    Seal shall be maintained on any device other than brake-pipe cut-out 
cock (double-heading cock), by means of which the operation of the 
pneumatic portion of automatic train-stop or train-control apparatus can 
be cut out.



Sec. 236.554  Rate of pressure reduction; equalizing reservoir or 

brake pipe.

    The equalizing-reservoir pressure or brake-pipe pressure reduction 
during an automatic brake application shall be at a rate not less than 
that which results from a manual service application.



Sec. 236.555  Repaired or rewound receiver coil.

    Receiver coil which has been repaired or rewound shall have the same 
operating characteristics which it possessed originally or as currently 
specified for new equipment.



Sec. 236.556  Adjustment of relay.

    Change in adjustment of relay shall be made only in a shop equipped 
for that purpose except when receiver coils, electro-pneumatic valve, or 
other essential part of the equipment is replaced. Irregularities in 
power-supply voltage or other variable factors in the circuit shall not 
be compensated for by adjustment of the relay.



Sec. 236.557  Receiver; location with respect to rail.

    (a) Receiver of intermittent inductive automatic train stop device 
of the inert roadway element type shall be maintained with bottom of the 
receiver at a height above the plane of the tops of the rails, and with 
its outer edge at a horizontal distance from the gage side of the 
nearest rail, in accordance with specifications of the carrier.
    (b) Receiver of continuous inductive automatic cab signal, train 
stop, or train control device of locomotive equipped with onboard test 
equipment, shall be maintained with the bottom of the receiver at a 
height above the plane of the tops of the rails, and with its outer edge 
at a horizontal distance from the gage side of the nearest rail, in 
accordance with specifications of the carrier.

[49 FR 3387, Jan. 26, 1984]



Sec. Sec. 236.558-236.559  [Reserved]



Sec. 236.560  Contact element, mechanical trip type; location with 

respect to rail.

    Contact element of automatic train stop device of the mechanical 
trip type shall be maintained at a height above the plane of the tops of 
the rails, and at a horizontal distance from the gage side of the rail, 
in accordance with specifications of the carrier.

[49 FR 3387, Jan. 26, 1984]



Sec. 236.561  [Reserved]



Sec. 236.562  Minimum rail current required.

    The minimum rail current required to restore the locomotive 
equipment of continuous inductive automatic train stop or train control 
device to normal

[[Page 622]]

condition or to obtain a proceed indication of automatic cab signal 
device (pick-up) shall be in accordance with specifications of the 
carrier.

[49 FR 3387, Jan. 26, 1984]



Sec. 236.563  Delay time.

    Delay time of automatic train stop or train control system shall not 
exceed 8 seconds and the spacing of signals to meet the requirements of 
Sec. 236.24 shall take into consideration the delay time.



Sec. 236.564  Acknowledging time.

    Acknowledging time of intermittent automatic train-stop device shall 
be not more than 30 seconds.



Sec. 236.565  Provision made for preventing operation of pneumatic 

brake-applying apparatus by double-heading cock; requirement.

    Where provision is made for preventing the operation of the 
pneumatic brake-applying appartus of an automatic train stop or train 
control device when the double-heading cock is placed in double-heading 
position, the automatic train stop or train control device shall not be 
cut out before communication is closed between the engineman's automatic 
brake valve and the brake pipe, when operating double-heading cock 
toward double-heading position.



Sec. 236.566  Locomotive of each train operating in train stop, train 

control or cab signal territory; equipped.

    The locomotive from which brakes are controlled, of each train 
operating in automatic train stop, train control, or cab signal 
territory shall be equipped with apparatus responsive to the roadway 
equipment installed on all or any part of the route traversed, and such 
apparatus shall be in operative condition.



Sec. 236.567  Restrictions imposed when device fails and/or is cut out 

en route.

    Where an automatic train stop, train control, or cab signal device 
fails and/or is cut out enroute, train may proceed at restricted speed 
or if an automatic block signal system is in operation according to 
signal indication but not to exceed medium speed, to the next available 
point of communication where report must be made to a designated 
officer. Where no automatic block signal system is in use train shall be 
permitted to proceed at restricted speed or where automatic block signal 
system is in operation according to signal indication but not to exceed 
medium speed to a point where absolute block can be established. Where 
an absolute block is established in advance of the train on which the 
device is inoperative train may proceed at not to exceed 79 miles per 
hour.



Sec. 236.568  Difference between speeds authorized by roadway signal 

and cab signal; action required.

    If for any reason a cab signal authorizes a speed different from 
that authorized by a roadway signal, when a train enters the block 
governed by such roadway signal, the lower speed shall not be exceeded.

                      Inspection and Tests; Roadway



Sec. 236.576  Roadway element.

    Roadway elements, except track circuits, including those for test 
purposes, shall be gaged monthly for height and alinement, and shall be 
tested at least every 6 months.



Sec. 236.577  Test, acknowledgement, and cut-in circuits.

    Test, acknowledgement, and cut-in circuits shall be tested at least 
once every twelve months.

[49 FR 3387, Jan. 26, 1984]

                    Inspection and Tests; Locomotive



Sec. 236.586  Daily or after trip test.

    (a) Except where tests prescribed by Sec. 236.588 are performed at 
intervals of not more than 2 months, each locomotive equipped with an 
automatic cab signal or train stop or train control device operating in 
equipped territory shall be inspected for damage to the equipment and 
tested at least once each calendar day or within 24 hours before 
departure upon each trip.
    (b) Each equipped locomotive shall be tested to determine the 
locomotive equipment is responsive to the wayside equipment and shall be 
cycled to determine the device functions as intended.

[[Page 623]]

    (c) Each locomotive equipped with intermittent inductive automatic 
train stop or non-coded continuous inductive automatic train stop or 
non-coded continuous inductive automatic train control device shall be 
tested to determine that the pickup of the device is within specified 
limits.

[49 FR 3387, Jan. 26, 1984]



Sec. 236.587  Departure test.

    (a) The automatic train stop, train control, or cab signal apparatus 
on each locomotive, except a locomotive or a multiple-unit car equipped 
with mechanical trip stop, shall be tested using one of the following 
methods:
    (1) Operation over track elements;
    (2) Operation over test circuit;
    (3) Use of portable test equipment; or
    (4) Use of onboard test device.
    (b) The test shall be made on departure of the locomotive from its 
initial terminal unless that apparatus will be cut out between the 
initial terminal and the equipped territory. If the apparatus is cut out 
between the initial terminal and the equipped territory the test shall 
be made prior to entering equipped territory.
    (c) If a locomotive makes more than one trip in any 24-hour period, 
only one departure test is required in such 24-hour period.
    (d)(1) Whoever performs the test shall certify in writing that such 
test was properly performed. The certification and the test results 
shall be posted in the cab of the locomotive and a copy of the 
certification and test results left at the test location for filing in 
the office of the supervisory official having jurisdiction.
    (2) If it is impractical to leave a copy of the certification and 
test results at the location of the test, the test results shall be 
transmitted to either (i) the dispatcher or (ii) one other designated 
individual at each location, who shall keep a written record of the test 
results and the name of the person performing the test. These records 
shall be retained for at least 92 days.

[49 FR 3387, Jan. 26, 1984, as amended at 53 FR 37313, Sept. 26, 1988]

    Effective Date Note: At 49 FR 3387, Jan. 26, 1984, Sec. 236.587 was 
revised. This section contains information collection and recordkeeping 
requirements and will not become effective until approval has been given 
by the Office of Management and Budget.



Sec. 236.588  Periodic test.

    Except as provided in Sec. 236.586, periodic test of the automatic 
train stop, train control, or cab signal apparatus shall be made at 
least once every 92 days, and on multiple-unit cars as specified by the 
carrier, subject to approval by the FRA.

[49 FR 3387, Jan. 26, 1984]



Sec. 236.589  Relays.

    (a) Each relay shall be removed from service, subjected to thorough 
test, necessary repairs and adjustments made, and shall not be replaced 
in service unless its operating characteristics are in accordance with 
the limits within which such relay is designed to operate, as follows:
    (1) Master or primary relays of torque type depending on spring 
tension to return contacts to deenergized position in noncoded 
continuous inductive automatic train stop or train control system, at 
least once every two years; and
    (2) All other relays, at least once every six years.
    (b) [Reserved]

[49 FR 3387, Jan. 26, 1984]



Sec. 236.590  Pneumatic apparatus.

    Automatic train stop, train control, or cab signal pneumatic 
apparatus shall be inspected, cleaned, and the results of such 
inspection recorded as provided by Sec. 229.29(a). When a locomotive 
with automatic train stop, train control, or cab signal pneumatic 
apparatus receives out-of-use credit pursuant to Sec. 229.33, the 
automatic train stop, train control, or cab signal apparatus shall be 
tested in accordance with Sec. 236.588 prior to the locomotive being 
placed in service.

[61 FR 33873, July 1, 1996]

[[Page 624]]