Automatic Train Stop

equipment for automatically stopping a railroad train in case the locomotive engineer does not react to the signal which indicates a stop or a reduction in speed.

The automatic train stop system includes track elements (such as transmitters, relays, and inductors) which are connected to the signaling equipment and which are automatically switched on so they can act on the locomotive’s braking system if the signal indicates a stop or a reduction in speed. Subways in the USSR use a mechanically acting type of automatic train stop. If the engineer receives the light signal in time, he can switch off the track element of the automatic train stop before it has a chance to activate the brakes. He can then control the braking manually. Switching off the automatic train stop is done by a manually controlled mechanism known as the rukoiatka bditel’ nosti (alert lever). Use of the automatic train stop eliminates the possibility of accidents caused by locomotive engineers’ lack of attention to signal lights.