CFR › Title 49 › Part 236 Part 236 — Rules, Standards, and Instructions Governing the Installation, Inspection, Maintenance, and Repair of Signal and Train Control Systems, Devices, and Appliances Subpart A — Rules and Instructions: All Systems § 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. § 236.26 — 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. § 236.73 — Open-wire transmission line; clearance to other circuits. § 236.74 — Protection of insulated wire; splice in underground wire. § 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. Subpart B — Automatic Block Signal Systems Subpart C — Interlocking § 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. § 236.314 — 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. § 236.334 — 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. § 236.386 — Restoring feature on power switches. § 236.387 — Movable bridge locking. Subpart D — Traffic Control Systems Subpart E — Automatic Train Stop, Train Control and Cab Signal Systems Subpart F — Dragging Equipment and Slide Detectors and Other Similar Protective Devices Subpart G — Definitions § 236.700 — Definitions. § 236.701 — Application, brake; full service. § 236.702 — Arm, semaphore. § 236.703 — Aspect. § 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. § 236.717 — 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. § 236.749 — 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. § 236.782 — 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. Subpart H — Standards for Processor-Based Signal and Train Control Systems Subpart I — Positive Train Control Systems