Glossary of Railway Operation and Control
last update: 2018-06-26
Abbr. to AUTOMATIC BLOCK SIGNALLING
See: BLOCK SECTION
ABSOLUTE PERMISSIVE BLOCK (APB)
An automatic block system on single lines on North American railways, which is completely controlled by track circuits providing protection against opposing and following movements without opposite locking.
Abbr. to ABSOLUTE PERMISSIVE BLOCK
1) A signal that must not be passed in stop position without permission from the operator.
2) An interlocking signal with a stop aspect that applies both to train movements and to shunting movements.
Form of route locking that comes into force after the train has occupied the approach section.
Another term for an outer home signal, which is mainly used in North American transit railway system.
A method to simulate railroad operations by stochastically generated train paths. The different train classes are generated one after the other (i.g. asynchronous) in accordance to their priority. Train path conflicts are solved by scheduling rules. (see also: SYNCHRONOUS SIMULATION)
Abbr. to AUTOMATIC ROUTE SETTING
Abbr. to AUTOMATIC TRAIN CONTROL
Abbr. to AUTOMATIC TRAIN OPERATION
Abbr. to AUTOMATIC TRAIN PROTECTION
Abbr. to AUTOMATIC TRAIN STOP
AUTOMATIC BLOCK SIGNALLING
A form of operation in which fixed block signals are controlled by an automatic block system.
AUTOMATIC POINT SETTING
An appliance that provides an automatic setting of switches when a route is lined up.
AUTOMATIC ROUTE SETTING (ARS)
A system that provides the automatic setting of the proper route when a train approaches a signal. (see also: DESTINATION-BASED AUTOMATIC ROUTE SETTING, TIMETABLE-BASED AUTOMATIC ROUTE SETTING)
A signal that is controlled automatically by the trains moving along the line.
AUTOMATIC TRAIN CONTROL (ATC)
1) Another term for a continuous automatic train protection (ATP) system
2) An automatic train protection (ATP) system that is combined with a device for automatic train operation (ATO).
AUTOMATIC TRAIN OPERATION (ATO)
A system that guides the train automatically by the information provided by an ATP system.
AUTOMATIC TRAIN PROTECTION (ATP)
A system that transmits information about movement authorities and speed limits from the line to the train to cause automatic braking if the train ignores the valid limits. (see also: INTERMITTENT ATP, CONTINUOUS ATP)
AUTOMATIC TRAIN STOP (ATS)
1) A simple form of an intermittent ATP system that only provides an automatic train stop when passing a stop signal but no braking curve supervision in approach to a stop signal.
2) The part of an ATP system that automatically applies the train brakes when the engineer fails to acknowledge a restrictive signal.
A track clear detection system consisting of counting points at both ends of a section and a counter connected to the counting points. The occupancy of a section is detected by comparing the number of axles which enter the section with the number of axles which leave the section.
BERTH TRACK CIRCUIT
The track circuit that is immediately on the approach to a signal. That term is mainly used in British signalling.
A signalling system for two-way working.
BLOCK AND LOCK SYSTEM
Another term for interlocked manual block.
A section of track in a fixed block system, which a train may only enter when it is not occupied by other vehicles.
A signal that governs train movements into a block section.
The percentage of the braking weight on the actual weight of a vehicle or train. The braking percentage may exceed 100 %. This value is mainly used for braking evaluation on UIC railways. (see also: BRAKING RATIO)
The brake cylinder force divided by the weight of the vehicle. This value is mainly use for braking evaluation on North American railways. (see also: BRAKING PERCENTAGE)
The weight, the brake of a vehicle can safely bring to a stop under specified conditions. The braking weight is determined by standardised braking tests and may exceed the actual weight of the vehicle. (see also: BRAKING PERCENTAGE, BRAKING RATIO)
Kind of a bumper as used by railways on which the vehicles are equipped with buffers.
An extra time that is added to the minimum line headway to avoid the transmission of small delays.
A device that prevents vehicles from overrunning the dead-end of a stub track.
A staffed car at the rear end of freight trains on US railways. Today, a caboose is only required on lines with time spacing.
The usage of methods of railroad operations research to determine the capacity of lines, interlockings, terminals and yards. (see also: ANALYTICAL CAPACITY RESEARCH, SYNCHRONOUS SIMULATION, ASYNCHRONOUS SIMULATION)
A form of tabular interlocking in which a route is established by a locking sequence which is effected by permanent and conditional lockings between points and signals. (see also: ROUTE-RELATED_LOCKING)
Signals that are displayed by trains on lines with timetable and train order operation to mark extra trains and trains that are divided in sections.
A track in the classification bowl designated to a specific destination.
CLOCK FACE TIMETABLE
Another term for a cyclic timetable
1) A fixed block system in which the line is blocked in normal state and only cleared when a train is going to enter the block section.
2) An automatic block system, in which the automatic block signals show a stop aspect as the normal indication.
CODED TRACK CIRCUIT
A track circuit in which the track current is overlaid by a code that contains signal information.
A delay that was transmitted from another train. (see also: INITIAL DELAY)
Another term for collateral delay.
The total time comsumed by headways within a considered period.
An ATP system in which the train receives data at all times in order to control the protection system.
CONTROLLED MANUAL BLOCK
A manual block system in which the signals are operated manually and controlled by continuous track circuits, requiring co-operation between the operators of adjacent block stations.
A signal that is locally or remotely controlled by an operator.
An arrangement of corresponding turnouts providing a connection between two parallel tracks.
Abbr. to CENTRALISED TRAFFIC CONTROL
A single car or a group of coupled cars that run down a hump.
A territory with a non-signalled operation.
A subyard of a classification yard in which trains are prepared for departure.
DEPENDENT POINT LOCK
A point lock that is actuated by the same device as that which drives the points.
DERAILER(brit.), DERAIL (am.)
A flank protection device that would derail an unsafe movement before it could join the protected route.
DESTINATION-BASED AUTOMATIC ROUTE SETTING
An automatic route setting system in which a route to the proper destination of a train is set up regardless of the scheduled train sequence in the timetable. (see also: TIMETABLE-BASED AUTOMATIC ROUTE SETTING)
Another term for a torpedo. This term is mainly used outside of North America.
The inner part of a crossing where the rails form a diamond shape.
A signal that provides an approach aspect to a following signal but that cannot show a stop aspect. A distant signal does not limit a block section.
DOUBLE SLIP SWITCH
North American Term for a double slip.
North American term for a special signal indication for authorizing yard movements.
Abbr. to DIRECT TRAFFIC CONTROL
DUAL CONTROL POINTS
Remote-controlled points, that can also be hand-operated.
DUAL PROTECTIVE POINTS
See: SELECTIVE PROTECTIVE POINTS
A brake system, in which the braking force is produced by the eddy-current iduced in the rails by an electro magnet moving above the rail without touching the rail surface. (see also: MAGNETIC RAIL BRAKE)
An interlocking system in which the interlocking is achieved by a mechanical lever frame with miniature levers and the switches and signals are operated by electric motors and are controlled electrically.
An interlocking system in which the interlocking is achieved by a mechanical lever frame and with miniature levers the switches and signals are operated by pneumatic cylinder drives and are controlled electrically.
EMERGENCY ROUTE RELEASE
A manually initiated release of a route or parts of a route if normal route release fails after the passage of a train. (see also: ROUTE CANCELLATION
A timetable for official use by railroad employees.
END OF TRAIN TELEMETRY (EOT), FLASHING REAR END DEVICE (FRED)
A device with an integrated rear end marker which is mounted at the rear car of a train and connected to the airbrake pipe to check train integrity by radio transmission to the leading engine.
A form of operating an interlocking machine by pushing a bottom at the entrance and the exit of a route.
Abbr. to END OF TRAIN TELEMETRY
Abbr. to EUROPEAN TRAIN CONTROL SYSTEM
ETCS level 3
An continuous ATP system following the ETCS standard that that combines radio-based train control with radio-based train separation based on moving block or virtual block. (see also: ETCS level 2, ETCS level 2)
1) An interlocking signal that governs train movements to leave a station track. It is also called a station exit signal. (mainly used outside North America).
2) North American term for the opposing interlocking signal a train passes when leaving interlocking limits.
3) An interlocking signal at the exit of an interlocked route. (see also: ENTRANCE SIGNAL)
The percentage of the consumed capacity
A train that does not run on a scheduled train path.
FACING POINT MOVEMENT
A movement on a turnout in which the points face approaching traffic.
FIXED INTERVAL TIMETABLE
Another term for a clock face timetable.
A member of the train crew who provides flag protection.
The locking of flank points in the protective position
Another term for a flank area.
FLASHING REAR END DEVICE (FRED)
See: END OF TRAIN TELEMETRY
A shunting method in which vehicles are moved by a locomotive. (see also: GRAVITY SHUNTING)
1) An automatic mode of an interlocking signal in which the route remains in a locked state and the signal works like an automatic block signal
2) A scheduling principle in which trains of equal speed or direction are assembled into fleets.
Another term for a classification yard (mainly used outside of North America).
FOULING POINT INDICATOR
A ground mounted sign to mark the fouling point.
Abbr. to FLASHING REAR END DEVICE
A track arrangement found on double-track lines that uses a frog to cross the inner rail of one track over the inner rail of another.
An interlocking system in which the track elements are represented by logical objects connected to each other in form of the track layout.
A classification yard that is set up on a continuous falling gradient. Compared with a hump yard, a gravity yard requires less use of shunting locomotives. (see also: FLAT YARD, GRIDIRON YARD)
HOME SIGNAL LIMITS
A track layout that is protected by opposing home signals. On North American railways, the home signal limits always equal the interlocking limits. On most railways outside of North America home signal limits may contain station tracks and successive interlocking signals.
The procedure of gravity shunting in a hump yard.
An electrical appliance that enables the return current of electric traction to pass insulated rail joints.
INDEPENDENT POINT LOCK
A point lock that is actuated by a separate device from that which drives the points.
A delay that was not transmitted from another train. (see also: COLLATERAL DELAY)
INSULATED RAIL JOINT
A rail joint that ensures electrical insulation of adjacent rails to limit a track circuit.
INTERLOCKED MANUAL BLOCK
A manual block system in which the block instruments are interlocked with the signals.
An area with interlocked points and signals.
1) Interconnection of signalling components and systems designed so that no conflicting movements can be signalled.
2) An arrangement of points and signals interconnected in a way that each movement follows the other in a proper and safe sequence.
North American term for the the trackage within the limits of an interlocking.
A signal that governs a route through an interlocking.
A location from which an interlocking is operated.
A control system of an interlocking area
Another term for a locking table.
North American term for an interlocking station.
Points that are located between two interlocking signals in a way that a train that is waiting at the signal ahead would not clear the points. Intermediate switches must be interlocked both with the signal in rear and with the signal in advance.
An ATP system in which the data is transmitted to the train at discrete points along the track.
JOINTLESS TRACK CIRCUIT
A track circuit that uses an AC audio frequency current, so that the working length is limited by the capacitive and inductive track characteristics without a need for insulated rail joints.
An arrangement of tracks and turnouts in which a line is joined by another one.
A group of parallel tracks connected by a ladder track.
The runnings resistance produced by the grade and the curvature of the line. (see also: TRAIN RESISTANCE)
Another term for a locking table.
A tabular sheet that contains all interlocking dependencies of an interlocking.
A track that is used for passing and overtaking trains. This term is mainly used outside of North America. (see also: SIDING)
MAGNETIC RAIL BRAKE
A brake system in which the braking force is produced by an electro magnet pressed on the rail surface. (see also: EDDY-CURRENT BRAKE)
An interlocked route governed by a main signal.
Another term for route holding.
The tracks that may be used for regular train movements.
Another term for a classification yard (mainly used outside of North America).
An interlocking system in which the interlocking is achieved by a mechanical lever frame and the switches and signals are operated by muscle power with rod or wire transmission.
An interlocking system in which the interlocking is achieved by software.
NON SIGNAL-CONTROLLED OPERATION
An operating procedure in which the traffic is controlled by verbal or written authority. A non signal-controlled operation may be combined with a signalling system as a safety overlay. (see also: SIGNAL-CONTROLLED OPERATION)
A form of a non signal-controlled operation in which the traffic is controlled by verbal or written authority and the train separation is not protected by a signalling system.
Abbr. to ENTRANCE-EXIT OPERATION
ONE-TRAIN WORKING (OTW)
An operating procedure for single track branches based on the rule that on the entire line, only one train is allowed at a time.
1)A fixed block system in which the line is cleared (open) in normal state and only blocked as long as a train has occupied the block section.
2) An automatic block system, in which the automatic block signals show a proceed aspect as the normal indication.
An employee who operates signalling appliances. (see also: TRAIN CONTROL OPERATOR)
A system of operating rules and technical appliances to operate trains on a railway infrastructure.
Another term for initial delay.
A certain length of track beyond a signal that must not be occupied as long a train is approaching this signal.
Another term for shared overlaps.
Another term for a clock face timetable.
A signal that may be cautiously passed in stop position after the train has stopped at the signal. After passing a permissive signal in stop position the movement in the next block section must be made at restricted speed.
A sign that indicates the position of points.
The movable parts of a turnout that are operated to set up different routes.
POSITIVE TRAIN CONTROL (PTC)
An advanced automatic arain protection system that enforces movement authorities, speed restrictions (signal and civil), and protection of roadway workers. This term is mainly used for radio-based systems in North America.
Another term for initial delay.
Another term for a flank points
Abbr. to POSITIVE TRAIN CONTROL
RADIO-BASED TRAIN CONTROL
A form of operation in which the movement authorities are issued by a radio block centre.
RADIO ELECTRONIC TOKEN BLOCK (RETB)
A form of radio-based train control in which the movement authority for a block section is issued in form of an electronic token, which is transmitted by radio from the radio block CENTRE to the train. After the train has cleared the section the token is send back to the radio block centre.
REAR END MARKER
A marker at the rear end of a train.
A subyard of classification yard in which the incoming trains arrive.
RECOVERABILITY OF THE TIMETABLE
The ability of a timetable to reduce the consequences of delays.
An interlocking system in which the interlocking is achieved by relay circuits.
REMOTE FLANK PROTECTION
A flank protection that is provided by an element that is not directly adjacent to the route to be protected.
An interlocking appliance that prevents a second operation of a control unit after certain conditions have been met.
A path through an interlocking, along which an authorised movement is to be made.
A manually initiated release of a locked route after having restored the signal. (see also: EMERGENCY ROUTE RELEASE)
ROUTE CLEARING POINT
A point that a train must have cleared completely before a locked route or sections of a locked route may be released.
ROUTE CONFLICT RATE
The number of conflicting route combinations divided by the total number of route combinations of a route node.
ROUTE CONFLICT TABLE
A sheet used for capacity research containing all route conflicts of a route node.
The selection of a route while a conflicting route has not yet released. After the conflicting route has released the preselected route will be setted up automatically.
A form of tabular interlocking in which all elements of a route are locked at once by a route locking element that releases the signal to be cleared. The points and signals are not directly connected by locking sequences. (see also: CASCADE LOCKING)
A signalling system in which the facing point signals indicate the route respectively the direction in which the train is being sent.
Another term for a main track.
SCHEDULED WAITING TIME
The waiting time that is needed for a scheduled passing and overtaking and to synchronise the schedules of a cyclic interval timetable.
A colour light signal with light units in which the aspect is given by a mechanism placing one of a number of roundels of the colour required, situated near the focus of the lens unit, in front of the lamp.
Another term for collateral delay.
North American term for tracks that are not used for regular train movements.
British term for a signal that governs train movements to leave station limits.
A form of overlap protection, in which the operator, when setting up a route, can select one of several possible overlaps. In difference to swinging overlaps, once the signal has been cleared, the overlap cannot be changed without cancelling the route.
SELF-SELECTIVE PROTECTIVE POINTS
flank points that would receive competing flank protection requests for both positions from different route elements of the same route. There must determined a position for the points to be locked in.
A controlled signal that my be switched into automatic mode.
Two or more overlaps simultanously leading into the same track section without causing a route conflict.
A proceed aspect allowing a shunting move to pass a signal.
Movements other than train movements accomplished at restricted speed within designated limits for making up trains, moving vehicles between tracks and similar purposes.
SHUNTING LIMIT BOARD
A fixed sign that must not be passed by shunting movements.
SHUNTING SIGNAL, SHUNT SIGNAL
A signal that is used to authorise shunting movements.
An locomotive with or without other vehicles that is authorised to run as a shunting movement.
1) North American term for a loop
2) Outside of North America, a shunting track that may not be used for regular train movements.
The appearance of a lineside signal, as viewed from the direction of an approaching train, or the appearance of a cab signal.
British term for an interlocking station.
Another term for an interlocking station.
SIGNAL CLEARING POINT
The point at the end of the overlap a train must have cleared completely to release the block section in approach of the signal.
A form of DTC in which the line is equipped with a simplified signalling system as a safety overlay.
A form of TWC in which the line is equipped with a simplified signalling system as a safety overlay.
The information that is given by a signal aspect.
British term for a TRAIN CONTROL OPERATOR
A method of capacity research in which, different from analytical capacity research, the running operational processes are modelled (mostly in a computer model). See also: ASYNCHRONOUS_SIMULATION, SYNCHRONOUS_SIMULATION.
SINGLE SLIP SWITCH
North American Term for a single slip.
SPUR TRACK, SPUR
A short stretch of track diverging from a main or branchline to serve a customer located away from the primary trackage.
1) A place designated in the timetable by name.
2) A place with a platform stop for passenger trains.
3) A short term for a station area (not used in North American and British signalling).
British term for the line from the home signal and the last section signal (starter signal) of the same direction which is controlled from the same signal box. This does not apply on a track circuit block line.
Another term for a station area.
STATION TRAFFIC DIAGRAM
A diagram that displays the scheduled occupation of the tracks in large stations and interlockings.
A dead-end track, usually equipped with a bumper.
SUBSEQUENT FLANK PROTECTION
selective protective points that, after the protected route element has released, will subsequently move to the protective position for another route element.
A train having precedence over another train.
North American term for shunting.
A method to simulate railway operations by modelling all partial processes of the operation in real time sequences. (see also: ASYNCHRONOUS SIMULATION)
An interlocking system in which the locking between signals and points is achieved in form of a locking table that contains all locking conditions for all routes. Tabular interlocking can be effected by cascade locking or by route-related locking.
Abbr. to TRAIN CONTROL OFFICER
TELEGRAPH ORDER SYSTEM
A South African train message system in which local operators exchange train messages over a section with intermediate unsignalled and unstaffed passing loops. At the entrance of the section a train gets an order that determines the meeting points with opposing trains within this section.
An assemblage of facilities provided at a terminus or at intermediate points of a line for the purpose of assembling, assorting, classifying and relaying trains.
TIME BLOCK SYSTEM
See: TIME SPACING
TIME SPACING, TIME BLOCK SYSTEM
A method of train separation in which a train must not follow another train until a specified time interval (usually 10 minutes) after the preceeding train has departed. In case of a delay, flag protection is required.
A document that contains the schedules of all trains of a line.
TIMETABLE AND TRAIN ORDER OPERATION
A traditional but today obsolete form of non-signalled operation on US railways in which trains are governed by the timetable. In dark territory, trains are separated by time spacing combined with flag protection. The traffic is regulated by priority rules and train orders which are issued by the dispatcher.
TIMETABLE-BASED AUTOMATIC ROUTE SETTING
An automatic route setting system in which all routes are set up both in compliance with the proper destination of the trains and with the scheduled train sequence of the timetable. (see also: DESTINATION-BASED AUTOMATIC ROUTE SETTING)
TOKEN BLOCK SYSTEM
A block system for single track lines in which the movement authority for a block section depends on the posession of a token which is handed out the train driver and handed back after clearing the section.
TOKENLESS BLOCK SYSTEM
A block system that works without exchanging a token between the control apparatus and the train driver.
See: INTERLOCKING TOWER
A track clear detection device consisting of an electrical circuit of which the rails of a section form a part. The clearance of the section is detected by a detection device at one end of the section which receives a current from a source at the other end of the section.
TRACK CIRCUIT BLOCK
British term for a method of working trains on a track where safety is ensured by continuous track clear detection devices (track circuits, axle counters) without the requirement to visually confirm that trains are complete.
A written form for authorisation of train movements in TWC territory.
TRACK WARRANT CONTROL (TWC)
A radio-based occupation control system for non-signalled lines in which trains may occupy main tracks only on the basis of the possession of a track warrant covering a precisely defined track segment of any length.
Another term for a dispatcher. This term is used on some railways outside of North America.
A diagram that contains the train paths of all trains that run on a line.
The traffic flow multiplied by the average train speed.
TRAIN, TRAIN MOVEMENT
A locomotive or self-propelled vehicle, alone or coupled to one or more vehicles, displaying a rear end marker with the authority to operate on main tracks in accordance to rules specified for train movements.
The method of authorising train movements.
TRAIN CONTROL OFFICER
South African term for an train control operator.
A number or an alphanumeric code for identification of a train and its schedule.
TRAIN DIRECTOR, TRAIN MOVEMENT DIRECTOR
An train control operator who controls a local interlocking or terminal area. A train director may supervise a number of levermen. This term is mainly used in the North American rules.
An order form that is used for traffic regulation on lines operated by timetable and train order.
TRAIN ORDER SIGNAL
A signal that indicates that an approaching train has to pick up train orders.
TRAIN ORDER STATION
A station where train orders may be picked up by trains.
TRAIN REGISTER BOOK
British term for a train record.
A document in which the dispatcher records all train movements and movement authorities.
Most simple form of an automatic train stop system (ATS) that is operated by mechanical contact between a trackside trip arm and a brake trip switch on the train.
A principle of protecting opposing movements on automatic block lines in which automatic signals of both directions are cleared in normal state but automatically restored to stop position when an opposing move has entered the line.
An assembly of rails, movable points and a frog, which effects the tangential branching of tracks and allows trains or vehicles to run over one track or another.
Abbr. to TRACK WARRANT CONTROL
An operating mode for double track lines where the tracks may be operated in both directions under block signal control.
Another term for a non-signalled operation.
WAITING TIME DIAGRAM
A diagram displaying the waiting time as a function of the traffic flow.
British term for a train route with a reduced overlap. A warner route is governed by an approach controlled signal that will only clear after the train has passed a warning aspects at the signal in rear.
1) An arrangement of tracks, other than main tracks, used for making up trains, storing cars and trains and other purposes
2) Australian term for the track system of a station area. (see also: CONSOLIDATED YARD)
1) North American term for a territory where yard engines may enter main tracks under simplified conditions without authority from the dispatcher
2) Australian term for the limits of a station area (see Autralian use of the term yard) that separates this area from the sections of the open line.