Code of Federal Regulations > Title 49 > Chapter II > Part 236 > Subpart C - Subpart C—Interlocking

U.S. Code of Federal Regulations

Regulations most recently checked for updates: Jan 21, 2026

STANDARDS

§ 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.

RULES AND INSTRUCTIONS

§ 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.

INSPECTION AND TESTS

§ 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.