Railway Signaling and Operations

Study Notes

An Absolute Block is a block that cannot be occupied by more than one train at a time.
An "A" Car is a rail car equipped with an Engineer's cab.

Adjacent Tracks are two or more tracks with track centerlines spaced less than 25 feet apart.
Adjacent Controlled Tracks are controlled tracks with track centers spaced 19 feet or less from the occupied track.

An Aspect is the appearance of a fixed signal viewed from the direction of an approaching train (e.g. green light).
An Automatic Block Signal System is a series of track sections governed by block signals actuated by trains, controlling the spacing of trains.
Automatic Block Signals are fixed signals at the entrance of a block or track section, governing the movement of approaching trains, identified by a number and the letter Z or D.

Automatic Train Control (ATC) is a system to enforce compliance with cab and wayside signal indications.
Automatic Train Operation (ATO) is a system where carborne equipment operates the train to and from stations, and opens and closes the doors, supervised by the Conductor and the Train Engineer.
An Automatic Train Stop is a device that causes a full emergency application of the brakes if a train fails to stop prior to a signal indicating STOP.

Ballast is sized rock or concrete placed on the roadbed to support the track structure, ties, and rail, and to hold the track in line and surface.

A Block is a length of track of defined limits, governed by block signals or verbal block indication.
Bridging occurs when a rail car becomes a conducting element between an energized section and a de-energized section of Third Rail.
A "C" Car is a rail car without an Engineer's cab.
Clearance is the suitable amount of space or distance required to allow a train or other vehicle to pass without obstruction.
A Collector Train is a train operated without customers for the collection of revenue at stations.
A Consist is two or more cars coupled together to make up a train.
A Contact Shoe is a device that conducts electrical current from the Third Rail to the railcar.
The Control Center is the central location from which PATH operations are controlled.