| A | B |
|---|
| Absolute Block | A length of track in with no no train or engine is permitted to enter while occupied by another train or engine |
| Absolute Signal | A block or interlocking signal designated by an A marker or absence of a number plate |
| Automatic Block Signal system | ABS |
| Automatic block signal system | a series of consecutive blocks governed by block signals, cab signals or both, actuated by a train, or engine or by certain conditions affecting the use of a block. |
| Automatic cab signal system | (ACS) |
| Automatic cab signal system | A system which provides for automatic operation of the cab signals and cab warning whistle |
| Automatic train stop system | ( ATS) |
| Automatic train stop system | A system acuated by way side inductors, so equipped so that its operation will automatically result in the application of the brakes until the train has been brought to a stop |
| Block | a length of track between consecutive block signals or from a block signal to the end of block signal limits, governed by blocked signals cab signals or both |
| Block occupancy indicator | An indicator used to convey information regarding block occupancy |
| Block signal | A fixed signal at the entrance of a block to govern trains and engines entering and using that block |
| Block system | A blcok or series of consecutive blocks within abs, acs, ctc, or interlocking limits |
| Cab signal | a Signal in the engineers compartment or cab, indicating a condition affecting the movement of a train or engine and used in conjunction with interlocking signals and in conjuction with or in lieu or block signals |
| Centralized traffic control | (CTC) |
| Centalized traffic control | A remotely controlled block system under which train movements are authorized by block signals indications |
| Control point | A location where absolute signals are controlled by a control operator control point may be designated by number |
| Controlled siding | A siiding within CTC or interlocking limits, the authorization for use of whick is governed by signal indication or control operator |
| Controlled signal | A absolute signal, the aspect of which is controlled by a control opeator |
| Crossover | A track connection between two adjacent tracks |
| Current or traffic | The movement of trains on a main track in one direction specified by the rules |
| Direct traffic control | (DTC) |
| Direct traffic control | A dtc block or series of dtc blocks wherein the movement of trains is authorized and goverened directly by the train dispatcher |
| Distant signal | A fixed signal outside of a block system, used to govern the approach to a block or interlocking signal, it will not convey information as to conditions affecting the use of the track between the distant signal and block or interlocking signal to which approach is governed, it will be identified by a D marker |
| Division | A portion of the railroad designated by the timetable |
| Double track | (DT) |
| Double track | Two main tracks, that current is opposite on each track |
| Control switch | A power operated switch also equipped for hand operation |
| DTC block | A specified length of main track which is identified by name, the name and limits of the block will be identified by wayside signs reading "Begin (Name) Block" and end (Name) block" and by mile post location in time table. |
| Electric Switch Lock | An electrically controled locking device affixed to ahand operated switch or derail to control it's use |
| Engine | A unit propelled by any form of energy, or a combination of such units operated from a single control,used in trai or yard service |
| Fixed Signal | A signal of permanent location indicating a condition affecting the movement of a train |
| Interlocking | An arrangement of signal appliances so interconnected that their movements must succeed each other in proper sequence. It may be operated manually or automaticlly. |
