Definition of Terms as they are applied to the Rules and Regulations of the Transportation Department.
ABSOLUTE-PERMISSIVE BLOCK. A block within which the movement of trains on a desigated section of track or tracks is directed by signals automatically controlled and without train-order authority and without superiority of trains.
A-PB. Abbreviation for Absolute-Permissive Block.
ABSOLUTE SIGNAL. A home signal, the indications of which authorize and govern the movement of trains and engines and supersede the superiority of trains.
APPROACH SIGNAL. A fixed signal used in connection with a home signal to govern the approach thereto.
AUTOMATIC BLOCK SIGNAL SYSTEM. A series of consecutive blocks governed by block signals actuated by a train, or by certain conditions affecting the use of a block.
ABS. Abbreviation for Automatic Block Signal System. ATS. Abbreviation for Automatic Train Stop.
BLOCK. A length of track between consecutive home signals governing in one direction; or from a home signal to sign reading "End of Block" or "Block System Limit"; the use of which by trains is governed by block signal.
BLOCK SIGNAL. A fixed signal at the entrance of a block, or within a block, to govern trains entering and using that block.
BLOCK SYSTEM. A series of consecutive blocks within A-PB, ABS, CTC and interlockings.
CENTRALIZED TRAFFIC CONTROL. A method of operation by means of which the movement of trains over routes and through blocks on a designated section of track or tracks is directed by signals and controlled from a designated point without requiring the use of train orders and without superiority of trains.
CTC. Abbreviation for Centralized Traffic Control.
CONTROLLED SIDING. A siding within CTC which may, or may not, have block signal control between fouling points on siding.
CROSSOVER. A connection between two adjacent parallel tracks.
CURRENT OF TRAFFIC. The movement of trains on a main track, in one direction, specified by the rules.
DISTANT SIGNAL. A fixed signal used in connection with a home signal to govern the approach thereto.
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