Part 236 — Rules, Standards, and Instructions Governing the Installation, Inspection, Maintenance, and Repair of Signal and Train Control Systems, Devices, and Appliances
Current through Sep 25, 2026
Authority: 49 U.S.C. 20102-20103, 20107, 20133, 20141, 20157, 20301-20303, 20306, 20501-20505, 20701-20703, 21301-21302, 21304; 28 U.S.C. 2461 note; and 49 CFR 1.89.
Source: 33 FR 19684, Dec. 25, 1968, unless otherwise noted.
Sections
- § 236.0 Applicability, minimum requirements, and penalties.
- § 236.1 Plans, where kept.
- § 236.2 Grounds.
- § 236.3 Locking of signal apparatus housings.
- § 236.4 Interference with normal functioning of device.
- § 236.5 Design of control circuits on closed circuit principle.
- § 236.6 Hand-operated switch equipped with switch circuit controller.
- § 236.7 Circuit controller operated by switch-and-lock movement.
- § 236.8 Operating characteristics of electromagnetic, electronic, or electrical apparatus.
- § 236.9 Selection of circuits through indicating or annunciating instruments.
- § 236.10 Electric locks, force drop type; where required.
- § 236.11 Adjustment, repair, or replacement of component.
- § 236.12 Spring switch signal protection; where required.
- § 236.13 Spring switch; selection of signal control circuits through circuit controller.
- § 236.14 Spring switch signal protection; requirements.
- § 236.15 Timetable instructions.
- § 236.16 Electric lock, main track releasing circuit.
- § 236.17 Pipe for operating connections, requirements.
- § 236.18 Software management control plan.
- § 236.21 Location of roadway signals.
- § 236.22 Semaphore signal arm; clearance to other objects.
- § 236.23 Aspects and indications.
- § 236.24 Spacing of roadway signals.
- § 236.25 [Reserved]
- § 236.26 Buffing device, maintenance.
- § 236.51 Track circuit requirements.
- § 236.52 Relayed cut-section.
- § 236.53 Track circuit feed at grade crossing.
- § 236.54 Minimum length of track circuit.
- § 236.55 Dead section; maximum length.
- § 236.56 Shunting sensitivity.
- § 236.57 Shunt and fouling wires.
- § 236.58 Turnout, fouling section.
- § 236.59 Insulated rail joints.
- § 236.60 Switch shunting circuit; use restricted.
- § 236.71 Signal wires on pole line and aerial cable.
- § 236.72 [Reserved]
- § 236.73 Open-wire transmission line; clearance to other circuits.
- § 236.74 Protection of insulated wire; splice in underground wire.
- § 236.75 [Reserved]
- § 236.76 Tagging of wires and interference of wires or tags with signal apparatus.
- § 236.101 Purpose of inspection and tests; removal from service of relay or device failing to meet test requirements.
- § 236.102 Semaphore or searchlight signal mechanism.
- § 236.103 Switch circuit controller or point detector.
- § 236.104 Shunt fouling circuit.
- § 236.105 Electric lock.
- § 236.106 Relays.
- § 236.107 Ground tests.
- § 236.108 Insulation resistance tests, wires in trunking and cables.
- § 236.109 Time releases, timing relays and timing devices.
- § 236.110 Results of tests.
- § 236.201 Track-circuit control of signals.
- § 236.202 Signal governing movements over hand-operated switch.
- § 236.203 Hand operated crossover between main tracks; protection.
- § 236.204 Track signaled for movements in both directions, requirements.
- § 236.205 Signal control circuits; requirements.
- § 236.206 Battery or power supply with respect to relay; location.
- § 236.207 Electric lock on hand-operated switch; control.
- § 236.301 Where signals shall be provided.
- § 236.302 Track circuits and route locking.
- § 236.303 Control circuits for signals, selection through circuit controller operated by switch points or by switch locking mechanism.
- § 236.304 Mechanical locking or same protection effected by circuits.
- § 236.305 Approach or time locking.
- § 236.306 Facing point lock or switch-and-lock movement.
- § 236.307 Indication locking.
- § 236.308 Mechanical or electric locking or electric circuits; requisites.
- § 236.309 Loss of shunt protection; where required.
- § 236.310 Signal governing approach to home signal.
- § 236.311 Signal control circuits, selection through track relays or devices functioning as track relays and through signal mechanism contacts and time releases at automatic interlocking.
- § 236.312 Movable bridge, interlocking of signal appliances with bridge devices.
- § 236.313 [Reserved]
- § 236.314 Electric lock for hand-operated switch or derail.
- § 236.326 Mechanical locking removed or disarranged; requirement for permitting train movements through interlocking.
- § 236.327 Switch, movable-point frog or split-point derail.
- § 236.328 Plunger of facing-point lock.
- § 236.329 Bolt lock.
- § 236.330 Locking dog of switch-and-lock movement.
- §§ 236.331-236.333 [Reserved]
- § 236.334 Point detector.
- § 236.335 Dogs, stops and trunnions of mechanical locking.
- § 236.336 Locking bed.
- § 236.337 Locking faces of mechanical locking; fit.
- § 236.338 Mechanical locking required in accordance with locking sheet and dog chart.
- § 236.339 Mechanical locking, maintenance requirements.
- § 236.340 Electromechanical interlocking machine; locking between electrical and mechanical levers.
- § 236.341 Latch shoes, rocker links, and quadrants.
- § 236.342 Switch circuit controller.
- § 236.376 Mechanical locking.
- § 236.377 Approach locking.
- § 236.378 Time locking.
- § 236.379 Route locking.
- § 236.380 Indication locking.
- § 236.381 Traffic locking.
- § 236.382 Switch obstruction test.
- § 236.383 Valve locks, valves, and valve magnets.
- § 236.384 Cross protection.
- § 236.385 [Reserved]
- § 236.386 Restoring feature on power switches.
- § 236.387 Movable bridge locking.
- § 236.401 Automatic block signal system and interlocking standards applicable to traffic control systems.
- § 236.402 Signals controlled by track circuits and control operator.
- § 236.403 Signals at controlled point.
- § 236.404 Signals at adjacent control points.
- § 236.405 Track signaled for movements in both directions, change of direction of traffic.
- § 236.406 [Reserved]
- § 236.407 Approach or time locking; where required.
- § 236.408 Route locking.
- § 236.409 [Reserved]
- § 236.410 Locking, hand-operated switch; requirements.
- § 236.426 Interlocking rules and instructions applicable to traffic control systems.
- § 236.476 Interlocking inspections and tests applicable to traffic control systems.
- § 236.501 Forestalling device and speed control.
- § 236.502 Automatic brake application, initiation by restrictive block conditions stopping distance in advance.
- § 236.503 Automatic brake application; initiation when predetermined rate of speed exceeded.
- § 236.504 Operation interconnected with automatic block-signal system.
- § 236.505 Proper operative relation between parts along roadway and parts on locomotive.
- § 236.506 Release of brakes after automatic application.
- § 236.507 Brake application; full service.
- § 236.508 Interference with application of brakes by means of brake valve.
- § 236.509 Two or more locomotives coupled.
- § 236.510 [Reserved]
- § 236.511 Cab signals controlled in accordance with block conditions stopping distance in advance.
- § 236.512 Cab signal indication when locomotive enters block where restrictive conditions obtain.
- § 236.513 Audible indicator.
- § 236.514 Interconnection of cab signal system with roadway signal system.
- § 236.515 Visibility of cab signals.
- § 236.516 Power supply.
- § 236.526 Roadway element not functioning properly.
- § 236.527 Roadway element insulation resistance.
- § 236.528 Restrictive condition resulting from open hand-operated switch; requirement.
- § 236.529 Roadway element inductor; height and distance from rail.
- § 236.530 [Reserved]
- § 236.531 Trip arm; height and distance from rail.
- § 236.532 Strap iron inductor; use restricted.
- § 236.533 [Reserved]
- § 236.534 Entrance to equipped territory; requirements.
- § 236.551 Power supply voltage; requirement.
- § 236.552 Insulation resistance; requirement.
- § 236.553 Seal, where required.
- § 236.554 Rate of pressure reduction; equalizing reservoir or brake pipe.
- § 236.555 Repaired or rewound receiver coil.
- § 236.556 Adjustment of relay.
- § 236.557 Receiver; location with respect to rail.
- §§ 236.558-236.559 [Reserved]
- § 236.560 Contact element, mechanical trip type; location with respect to rail.
- § 236.561 [Reserved]
- § 236.562 Minimum rail current required.
- § 236.563 Delay time.
- § 236.564 Acknowledging time.
- § 236.565 Provision made for preventing operation of pneumatic brake-applying apparatus by double-heading cock; requirement.
- § 236.566 Locomotive of each train operating in train stop, train control or cab signal territory; equipped.
- § 236.567 Restrictions imposed when device fails and/or is cut out en route.
- § 236.568 Difference between speeds authorized by roadway signal and cab signal; action required.
- § 236.576 Roadway element.
- § 236.577 Test, acknowledgement, and cut-in circuits.
- § 236.586 Daily or after trip test.
- § 236.587 Departure test.
- § 236.588 Periodic test.
- § 236.589 Relays.
- § 236.590 Pneumatic apparatus.
- § 236.601 Signals controlled by devices; location.
- § 236.700 Definitions.
- § 236.701 Application, brake; full service.
- § 236.702 Arm, semaphore.
- § 236.703 Aspect.
- § 236.704 [Reserved]
- § 236.705 Bar, locking.
- § 236.706 Bed, locking.
- § 236.707 Blade, semaphore.
- § 236.708 Block.
- § 236.709 Block, absolute.
- § 236.710 Block, latch.
- § 236.711 Bond, rail joint.
- § 236.712 Brake pipe.
- § 236.713 Bridge, movable.
- § 236.714 Cab.
- §§ 236.715-236.716 [Reserved]
- § 236.717 Characteristics, operating.
- § 236.718 Chart, dog.
- § 236.719 Circuit, acknowledgment.
- § 236.720 Circuit, common return.
- § 236.721 Circuit, control.
- § 236.722 Circuit, cut-in.
- § 236.723 Circuit, double wire; line.
- § 236.724 Circuit, shunt fouling.
- § 236.725 Circuit, switch shunting.
- § 236.726 Circuit, track.
- § 236.727 Circuit, track; coded.
- § 236.728 Circuit, trap.
- § 236.729 Cock, double heading.
- § 236.730 Coil, receiver.
- § 236.731 Controller, circuit.
- § 236.732 Controller, circuit; switch.
- § 236.733 Current, foreign.
- § 236.734 Current of traffic.
- § 236.735 Current, leakage.
- § 236.736 Cut-section.
- § 236.737 Cut-section, relayed.
- § 236.738 Detector, point.
- § 236.739 Device, acknowledging.
- § 236.740 Device, reset.
- § 236.741 Distance, stopping.
- § 236.742 Dog, locking.
- § 236.743 Dog, swing.
- § 236.744 Element, roadway.
- § 236.745 Face, locking.
- § 236.746 Feature, restoring.
- § 236.747 Forestall.
- § 236.748 [Reserved]
- § 236.749 Indication.
- § 236.750 Interlocking, automatic.
- § 236.751 Interlocking, manual.
- § 236.752 Joint, rail, insulated.
- § 236.753 Limits, interlocking.
- § 236.754 Line, open wire.
- § 236.755 Link, rocker.
- § 236.756 Lock, bolt.
- § 236.757 Lock, electric.
- § 236.758 Lock, electric, forced drop.
- § 236.759 Lock, facing point.
- § 236.760 Locking, approach.
- § 236.761 Locking, electric.
- § 236.762 Locking, indication.
- § 236.763 Locking, latch operated.
- § 236.764 Locking, lever operated.
- § 236.765 Locking, mechanical.
- § 236.766 Locking, movable bridge.
- § 236.767 Locking, route.
- § 236.768 Locking, time.
- § 236.769 Locking, traffic.
- § 236.770 Locomotive.
- § 236.771 Machine, control.
- § 236.772 Machine, interlocking.
- § 236.773 Movements, conflicting.
- § 236.774 Movement, facing.
- § 236.775 Movement, switch-and-lock.
- § 236.776 Movement, trailing.
- § 236.777 Operator, control.
- § 236.778 Piece, driving.
- § 236.779 Plate, top.
- § 236.780 Plunger, facing point lock.
- § 236.781 [Reserved]
- § 236.782 Point, controlled.
- § 236.783 Point, stop-indication.
- § 236.784 Position, deenergized.
- § 236.785 Position, false restrictive.
- § 236.786 Principle, closed circuit.
- § 236.787 Protection, cross.
- § 236.787a Railroad.
- § 236.788 Receiver.
- § 236.789 Relay, timing.
- § 236.790 Release, time.
- § 236.791 Release, value.
- § 236.792 Reservoir, equalizing.
- § 236.793 Rod, lock.
- § 236.794 Rod, up-and-down.
- § 236.795 Route.
- § 236.796 Routes, conflicting.
- § 236.797 Route, interlocked.
- § 236.798 Section, dead.
- § 236.799 Section, fouling.
- § 236.800 Sheet, locking.
- § 236.801 Shoe, latch.
- § 236.802 Shunt.
- § 236.802a Siding.
- § 236.803 Signal, approach.
- § 236.804 Signal, block.
- § 236.805 Signal, cab.
- § 236.806 Signal, home.
- § 236.807 Signal, interlocking.
- § 236.808 Signals, opposing.
- § 236.809 Signal, slotted mechanical.
- § 236.810 Spectacle, semaphore arm.
- § 236.811 Speed, medium.
- § 236.812 Speed, restricted.
- § 236.813 Speed, slow.
- § 236.813a State, most restrictive.
- § 236.814 Station, control.
- § 236.815 Stop.
- § 236.816 Superiority of trains.
- § 236.817 Switch, electro-pneumatic.
- § 236.818 Switch, facing point.
- § 236.819 Switch, hand operated.
- § 236.820 Switch, interlocked.
- § 236.820a Switch, power-operated.
- § 236.821 Switch, sectionalizing.
- § 236.822 Switch, spring.
- § 236.823 Switch, trailing point.
- § 236.824 System, automatic block signal.
- § 236.825 System, automatic train control.
- § 236.826 System, automatic train stop.
- § 236.827 System, block signal.
- § 236.828 System, traffic control.
- § 236.829 Terminal, initial.
- § 236.830 Time, acknowledging.
- § 236.831 Time, delay.
- § 236.831a Track, main.
- § 236.832 Train.
- § 236.833 Train, opposing.
- § 236.834 Trip.
- § 236.835 Trunking.
- § 236.836 Trunnion.
- § 236.837 Valve, electro-pneumatic.
- § 236.838 Wire, shunt.
- § 236.901 Purpose and scope.
- § 236.903 Definitions.
- § 236.905 Railroad Safety Program Plan (RSPP).
- § 236.907 Product Safety Plan (PSP).
- § 236.909 Minimum performance standard.
- § 236.911 Exclusions.
- § 236.913 Filing and approval of PSPs.
- § 236.915 Implementation and operation.
- § 236.917 Retention of records.
- § 236.919 Operations and Maintenance Manual.
- § 236.921 Training and qualification program, general.
- § 236.923 Task analysis and basic requirements.
- § 236.925 Training specific to control office personnel.
- § 236.927 Training specific to locomotive engineers and other operating personnel.
- § 236.929 Training specific to roadway workers.
- § 236.1001 Purpose and scope.
- § 236.1003 Definitions.
- § 236.1005 Requirements for Positive Train Control systems.
- § 236.1006 Equipping locomotives operating in PTC territory.
- § 236.1007 Additional requirements for high-speed service.
- § 236.1009 Procedural requirements.
- § 236.1011 PTC Implementation Plan content requirements.
- § 236.1013 PTC Development Plan and Notice of Product Intent content requirements and Type Approval.
- § 236.1015 PTC Safety Plan content requirements and PTC System Certification.
- § 236.1017 Independent third party Verification and Validation.
- § 236.1019 Main line track exceptions.
- § 236.1020 [Reserved]
- § 236.1021 Discontinuances, material modifications, and amendments.
- § 236.1023 Errors and malfunctions.
- § 236.1025 [Reserved]
- § 236.1027 PTC system exclusions.
- § 236.1029 PTC system use and failures.
- § 236.1031 Previously approved PTC systems.
- § 236.1033 Communications and security requirements.
- § 236.1035 Field testing requirements.
- § 236.1037 Records retention.
- § 236.1039 Operations and Maintenance Manual.
- § 236.1041 Training and qualification program, general.
- § 236.1043 Task analysis and basic requirements.
- § 236.1045 Training specific to office control personnel.
- § 236.1047 Training specific to locomotive engineers and other operating personnel.
- § 236.1049 Training specific to roadway workers.
- Appendix A to Part 236 [Reserved]
- Appendix B to Part 236—Risk Assessment Criteria
- Appendix C to Part 236—Safety Assurance Criteria and Processes
- Appendix D to Part 236—Independent Review of Verification and Validation
- Appendix E to Part 236—Human-Machine Interface (HMI) Design
- Appendix F to Part 236—Minimum Requirements of FRA Directed Independent Third-Party Assessment of PTC System Safety Verification and Validation