Page updated on 10 March 2024

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Terms

This web page states the definitions of railway terms.

A

ABS
Abbr. To Automatic Block Signalling
Absolute Block
See: Block Section
Absolute Block System
A fixed block system in which a train may enter a block section only after the last train ahead has completely cleared the block section and is protected by a stop signal.
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.
APB
Abbr. To Absolute Permissive Block
Absolute Signal
A signal that must not be passed in stop position without permission from the operator.
Analytical Capacity Research
A method of capacity research that calculates data from the infrastructure and timetable characteristics to determine and describe the capacity without simulation.
Approach-Controlled Signal
A signal that is cleared automatically on the approach of a train.
Approach Locking
Form of route locking that comes into force after the train has occupied the approach section.
Approach_Signal
Another term for an outer home signal, which is mainly used in North American transit railway system.
Approach Time
The running time between a signal that provides an approach aspect and the following signal.
Asynchronous Simulation
A method to simulate railroad operations by stochastically generated train paths. The different train classes are generated one after the other (i.e. asynchronous) in accordance to their priority. Train path conflicts are solved by scheduling rules. (see also: Synchronous Simulation)
ARS
Abbr. To Automatic Route Setting
ATC
Abbr. To Automatic Train Control
ATO
Abbr. To Automatic Train Operation
ATP
Abbr. To Automatic Train Protection
ATS
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 Block System
A block system in which the signals work automatically. Lines with an automatic block system must be equipped with track clear detection.
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)
Automatic Signal
A signal that is operated automatically.
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.
Axle counter
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.

B

Balise
A transponder that is used as a data point in an intermittent automatic train protection (ATP) system or as reference point for train location in radio-based train control.
Berth
The track section, on which a train comes to a halt at a stop signal. That term is mainly used in British signalling.
Berth Track Circuit
The track circuit that is immediately on the approach to a signal. That term is mainly used in British signalling.
Bidirectional Signalling
A signalling system for two-way working.
Block And Lock System
Another term for interlocked manual block.
Blocking
Assorting freight cars within a train into groups (blocks) bound for individual destinations.
Block Section
A section of track in a fixed block system, which a train may only enter when it is not occupied by other vehicles.
Block Signal
A signal that governs train movements into a block section.
Block System
A signalling system that provides a safe spacing of trains. Block systems may be divided into fixed block systems and moving block systems.
Blocking Time
The time interval in which a section of track is exclusively allocated to a train movement and therefore blocked for other trains.
Blocking Time Stairway
A graph displaying the blocking times of all block sections a train passes into a time-over-distance diagram.
Block Marker
A fixed sign that marks the limit of a block section in a cab signal territory.
Brakeman
A member of a train crew who assists the engineer in the train handling.
Braking Percentage
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)
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)
Braking Weight
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)
Branch line, Branch
A line diverging from a main line to serve smaller towns with low traffic.
Buffer Stop
Kind of a bumper as used by railways on which the vehicles are equipped with buffers.
Buffer Time
An extra time that is added to the minimum line headway to avoid the transmission of small delays.
Bumper
A device that prevents vehicles from overrunning the dead-end of a stub track.

C

Caboose
A staffed car at the rear end of freight trains on US railways. Today, a caboose is only required on lines with time spacing.
Cab Signalling
A signalling system that displays the movement authorities on the control panel in the locomotive cab.
Call-On Signal
A subsidiary signal that allows a train cautiously to pass a stop signal.
Capacity
The maximum traffic flow a piece of infrastructure (line, interlocking, terminal, yard) can handle under specified operating conditions.
Capacity Research
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)
Car Retarder
See: Retarder
Cascade Locking
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)
Centralised Traffic Control (CTC)
A control system in which the local interlockings are remote-controlled by a dispatcher and the trains are governed by signal indication.
Classification
Assembling freight cars into trains bound for specific destinations.
Classification Bowl
A sub yard of a classification yard which contains the classification tracks.
Classification Signal
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.
Classification Track
A track in the classification bowl designated to a specific destination.
Classification Yard (US)
A freight yard in which incoming cars are classified for new train destinations. (see also: Gravity Yard, Flat Yard)
Clearing Point
A point a train must have cleared completely before a signal or an interlocked route may be released.
Clock Face Timetable
Another term for a cyclic timetable
Closed Block
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.
Coded Track Circuit
A track circuit in which the track current is overlaid by a code that contains signal information.
Collateral Delay
A delay that was transmitted from another train. (see also: Initial Delay)
Colour Light Signal
A light signal that displays the Aspects by the colour of lights.
Colour Position Light Signal
A light signal which displays the aspects by the colour and the position of lights.
Command Interlocking
An interlocking system in which a signal in a dependent interlocking station can only be cleared after it has been remotely unlocked from the command interlocking station.
Command Interlocking Station
An interlocking station from which an interlocking signal in the district of a dependent interlocking station must be remotely unlocked to be cleared for a route.
Common Signal
A signal that applies to any of a group of converging tracks.
Conditional Crosslock
A crosslock that is only in effect as long as a route is set up or a signal is cleared. (see also: Permanent Crosslock)
Conditional Locking
An interlocking between points and a signal in which the locking of the points by clearing the signal depends on the position of other points.
Conductor
The head of a train crew.
Conflicting Locking
The interlocking between two conflicting routes that require one or more POINTS set in opposite positions. (see also: Plain Conflicting Routes, Opposing Locking)
Conflicting Routes
Interlocked routes that must not be set up at the same time. (see also: Plain Conflicting Routes, Special Conflicting Routes)
Consecutive Delay
Another term for collateral delay.
Consolidated Yard
Australian term for an area where interlockings controlled by one signalling location have intervening automatic signals.
Consumed Capacity
The total time comsumed by headways within a considered period.
Continuous ATP
An ATP system in which the train receives data at all times in order to control the protection system.
Control Centre
A centralised control system that controls the train movements in a large territory.
Controlled Cut
A humping control procedure, in which the cuts are retarded semi continuously by densely spaced small retarders. (see also: Free Cut)
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.
Controlled Point
A station where signals are remote-controlled from a control station.
Controlled Siding (CS)
A circuited siding in which train movements are governed by signals under control of a dispatcher or operator.
Controlled Signal
A signal that is locally or remotely controlled by an operator.
Control Length Of A Signal
The length of track beyond a signal that must be safe and clear as long the signal displays a proceed aspect.
Control Station

The dispatcher's office or the location where an operator is on duty and from which remote-controlled signal appliances are operated.

Crossing
An intersection of two tracks at grade.
Crosslock
An appliance that provides a permanent interlocking of points with a derailer or with other points.
Crossover
An arrangement of corresponding turnouts providing a connection between two parallel tracks.
Cross Traffic
Cars that arrive in the wrong system of a double-sided classification yard, so that these cars have to go over both humps to reach their destination train.
CTC
Abbr. To Centralised Traffic Control
Current Of Traffic
A direction specified by the rules for all train movements on a main track.
Cut
A single car or a group of coupled cars that run down a hump.
Cyclic Timetable
A timetable in which trains that belong to the same route are scheduled with fixed time intervals between their train paths.

D

Dark Territory
A territory with a non-signalled operation.
Departure Yard
A sub yard 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.
Dependent Interlocking Station
An interlocking station in which a signal can only be cleared after it has been remotely unlocked from the command interlocking station.
Derailer(UK), Derail (US)
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)
Destination Signal
An interlocking signal at the exit of an interlocked route. It is also called the exit signal of that route. (see also: Entrance Signal)
Detonator
Another term for a torpedo. This term is mainly used outside of North America.
Diamond
The inner part of a crossing where the rails form a diamond shape.
Direction Locking
A form of opposite locking in which a locked direction of travel is established on a block line that may consist of several block sections.
Direct Traffic Control (DTC)
A radio-based occupation control system for non-signalled lines in which the train crews receive exclusive authority to occupy one or more block sections.
Dispatcher
An employee who supervises the train movements of a line or a certain area. In CTC territory the dispatcher also does the work of an operator.
Distant Signal
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
A track layout that combines a crossing with four pairs of points to provide slip connections at both sides of the crossing.
Double Slip Switch (US)
North American Term for a double slip.
Drill Signal (US)
North American term for a special signal indication for authorizing yard movements.
DTC
Abbr. to DIRECT TRAFFIC CONTROL
Dual Control Points
Remote-controlled points, that can also be hand-operated.
Dual Protective Points
See: SELECTIVE PROTECTIVE POINTS
Dwarf Signal
A ground mounted signal.
Dwell Time
The total elapsed time from the time that a train stops in a station until the time it resumes moving.

E

Early Target Shooting
A humping control procedure, in which the braking target is the begin of the classification track. (see also: Target Shooting)
Eddy-Current Brake
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)
Electric Interlocking
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.
Electronic Interlocking
See: Microcomputer Interlocking
Electro-Pneumatic Interlocking
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
Employee's Timetable
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.
Engineer (US)
North American term for a train driver.
Entrance-Exit Operation
A form of operating an interlocking machine by pushing a bottom at the entrance and the exit of a route.
Entrance Signal
An interlocking signal at the entrance of an interlocked route. (see also: Exit Signal)
EOT
Abbr. To End Of Train Telemetry
ETCS
Abbr. To European Train Control System.
ETCS Level 1
An intermittent ATP system following the ETCS standard that uses controlled Eurobalises for transmission of control data. (see also: ETCS Level 2, ETCS Level 3)
ETCS Level 2
An continuous ATP system following the ETCS standard that that combines radio-based train control with a fixed block system. (see also: ETCS Level 2, ETCS Level 3)
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)
Eurobalise
A standardised balise for use in the European Train Control System
European Train Control System (ETCS)
European standard for an interoperable automatic train protection system for European railways. (see also: ETCS Level 1, ETCS lLevel 2, ETCS Level 3)
Exit Signal
  1. A 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)
Exploitation Rate
The percentage of the consumed capacity
Extra Train
A train that does not run on a scheduled train path.

F

Facing Point Movement
A movement on a turnout in which the points face approaching traffic.
Fixed Block System
A block system in which the track behind a train is sectionally cleared in form of fixed block sections.
Fixed Interval Timetable
Another term for a clock face timetable.
Flagman
A member of the train crew who provides flag protection.
Flag Protection
A method to protect a train by a member of the train crew who gives stop signals (fusees, flag signals, torpedos) to following and (if required) opposing trains.
Flank Area
The section of track between a flank protection device and the fouling point of the route to be protected.
Flank Locking
The locking of flank points in the protective position
Flank Protection
A method to prevent vehicles from running into a route, which is cleared for a train movement.
Flank Points
A points that are locked in a protective position to provide flank protection.
Flank Transfer Points
Points that are located between an element that provides remote flank protection and the route to be protected.
Flashing Rear End Device (FRED)
See: End Of Train Telemetry
Flat Shunting
A shunting method in which vehicles are moved by a locomotive. (see also: Gravity Shunting)
Flat Yard
A classification yard in which classification is done by flat shunting. (see also: Hump Yard)
Fleeted Signal
An interlocking signal on which fleeting is in effect.
Fleeting
  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.
Formation Yard
Another term for a classification yard (mainly used outside of North America).
Fouling Point
The limit of occupation of converging tracks at turnouts and crossings.
Fouling Point Indicator
A ground mounted sign to mark the fouling point. Interlocking Area
FRED
Abbr. To Flashing Rear End Device
Free Cut
A humping control procedure, in which the cuts are retarted only at a few locations by powerful retarders. (see also: Controlled Cut)
FROG
The part of a turnout, a crossing, or a gantlet, where the rails have an intersection which allows the wheel flanges to cross the running rail.

G

GANTLET
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.
Geographical Interlocking
An interlocking system in which the track elements are represented by logical objects connected to each other in form of the track layout.
Gravity Shunting
A shunting method in which vehicles run down a gradient driven by gravity into their classification tracks. (see also: Flat Shunting, Hump Yard, Gravity Yard)
Gravity Yard
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)
Gridiron Yard
An type of a gravity yard in which several successive ladders form a gridiron shaped track layout.
Ground Frame
A ground mounted small lever frame to enable a group of points to be locally controlled by train or yard crews.
Group Retarder
A retarder that serves a group of classification tracks. (see also: Master Retarder)

H

Headway
The time interval between two successive trains.
Home Signal
  1. A signal governing entrance to an interlocking.
  2. A signal governing entrance to a station track.
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.
Hump
An artificial hill in a hump yard where vehicles are pushed over to let gravity drive them into the classification tracks.
Humping
The procedure of gravity shunting in a hump yard.
Hump Yard
A classification yard in which the vehicles run down a hump into the classification bowl. (see also: Flat Yard, Gravity Yard)

I

Impedance Bonds
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.
Initial Delay
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.
Interlocking Area
An area with interlocked points and signals.
Interlocking
  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.
Interlocking Limits (US)
North American Term for the tracks between the outer opposing absolute signals of an interlocking.
Interlocking Plant (US)
North American term for the the trackage within the limits of an interlocking.
Interlocking Signal
A signal that governs a route through an interlocking.
Interlocking Station
A location from which an interlocking is operated.
Interlocking System
A control system of an interlocking area
Interlocking Table
Another term for a locking table.
Interlocking Tower (US)
North American term for an interlocking station.
Intermediate Block Signal
A block signal that is located between different interlockings.
Intermediate Interlocking Signal
An interlocking signal that is neither a home signal nor it governs a route to leave the interlocking area.
Intermediate Points
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.
Intermittent ATP
An ATP system in which the data is transmitted to the train at discrete points along the track.

J

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.
Junction
An arrangement of tracks and turnouts in which a line is joined by another one.

L

Ladder
A group of parallel tracks connected by a ladder track.
Ladder Track
A track that provides access to a series of parallel tracks.
Leaving Signal (US)
North American term for a signal that governs train movements to leave a siding, yard, or branchline.
Leverman
An employee who operates an interlocking machine (lever frame) under supervision of a train director.
Lever Sequence
The sequence in which the levers have to be operated to line up a route on an interlocking machine with cascade locking.
Light Signal

A signal in which the aspects are given by the color and/or position of lights.

Line Headway
The headway that results from the blocking time stairways of two successive trains.
Line Resistance
The runnings resistance produced by the grade and the curvature of the line. (see also: Train Resistance)
Locking Frame
A mechanical locking system that effects the interlocking between the levers of a mechanical, electric or electro-pneumatic interlocking machine.
Locking Sheet
Another term for a locking table.
Locking Table
A tabular sheet that contains all interlocking dependencies of an interlocking.
Loop
A track that is used for passing and overtaking trains. This term is mainly used outside of North America. (see also: Siding)

M

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)
Main Route
An interlocked route governed by a main signal.
Main Signal
A signal that governs train moMarshalling Yardvements. This term is used by railroads outside of North America to distinguish these signals from shunting signals.
Maintained Locking
Another term for route holding.
Main Tracks
The tracks that may be used for regular train movements.
Manual Block
A fixed block system in which the signals are operated manually and the clearing of the block sections is checked by local operators watching the rear end markers.
Manual Signal
A signal that is operated manually.
Marshalling Yard (UK)
Another term for a classification yard (mainly used outside of North America).
Master Retarder
The first retarder vehicles pass while running down a hump. (see also: Group Retarder)
Mechanical Interlocking
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.
Microcomputer Interlocking
An interlocking system in which the interlocking is achieved by software.
Minimum Running Time
The shortest running time as a result from a running time calculation.
Movable Frog
A pivoting or flexible frog that is operated by a point machine to close the rail gap at the frog in accordance to the route that is set up.
Movement Authority
The authority to move a train through a section of track up to a specified limit. (see also: Timetable Authority)
Moving Block System
A block system in which the track behind a train is cleared continously. (see also: Fixed Block System, Virtual Block System)
Moving-Up Signal
A signal placed between the home signal and the platform to allow a train to pass the home signal while a departing train ahead has not yet completely cleared the platform section.
Multiple-Block Signalling
A signalling system in which the main signals provide information about the clearance of more than one block section.
Multiple Home Signals
Another term for a signal arrangement in which a home signal is followed by one or more moving-up signals.
Multi-Unit Light Signal
A colour light signal with independent light units and every unit using one light.

N

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)
Non-Signalled 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.
Normal Running Time
The scheduled running time as the sum of the minimum running time and the recovery time.
Nx Operation
Abbr. To Entrance-Exit Operation

O

One-Block Signalling
A signalling system in which the main signals provide information about the clearance of only one block section.
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.
Open Block
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.
Open Line
Main tracks outside of station areas (not used in North American and British signalling).
Operating Procedure
A system of operating rules and technical appliances to operate trains on a railway infrastructure.
Operator
An employee who controls train movements.
Opposing Locking
The interlocking between opposing routes leading into the same track section.
Opposite Locking
The part of an interlocked block system to prevent opposing movements in single line operations. (see also: Direction Locking)
Original Delay
Another term for initial delay.
Outer Home Signal
An interlocking signal in approach to a home signal that does not directly protect points but that is interlocked with points within the overlap beyond the home signal.
Overlap
A certain length of track beyond a signal that must not be occupied as long a train is approaching this signal.
Overlapping Overlaps
Another term for shared overlaps.

P

Periodic Timetable
Another term for a clock face timetable.
Permanent Crosslock
A crosslock that is permanently in effect. (see also: Conditional Crosslock)
Permissive Signal
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.
Plain Conflicting Routes
Conflicting routes that require points set in opposite positions. (see also: Special Conflicting Routes)
Point Indicator
A sign that indicates the position of points.
Point Lock
A locking device that mechanically locks the points in a proper position to prevent unattended movements of the points and movable frogs.
Point Machine
A machine that is used to operate points, movable frogs or derailers.
Points
The movable parts of a turnout that are operated to set up different routes.
Position Light Signal
A light signal that indications are given by the position of two or more lights.
Positive Train Control (PTC) (US)
An advanced automatic train 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.
Primary Delay
Another term for initial delay.
Protection Signal
A signal that displays a stop aspect for protection purposes but that is not used to authorise regular train movements.
Protective Points
Another term for a flank points
PTC
Abbr. To Positive Train Control
Pure Running Time
The shortest possible running time between scheduled stops as a result from a running time calculation.

R

Radio-Based Train Control
A form of operation in which the movement authorities are issued by a radio block centre.
Radio Block Centre
A control centre to supervise and control train movements in a territory with radio-based train control.
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.
Receiving Yard
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.
Recovery Time
A time supplement that is added to the pure running time to enable a train to make up small delays.
Relay Interlocking
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.
Restricted Speed (US)
A speed that allows to stop short of a vehicle or obstruction. This term is mainly used on North American railways.
Retarder
A trackside braking device used in gravity shunting to control cars running down a hump.
Rigid Crossing
A crossing without movable frogs.
Rotation Locking
An interlocking appliance that prevents a second operation of a control unit after certain conditions have been met.
Route
A path through an interlocking, along which an authorised movement is to be made.
Route Cancellation
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 an interlocking.
Route Holding
A locking function that maintains all locking conditions of a route until the train has passed clear the clearing point of the relevant route elements.
Route Locking
The locking of all points as long a route is established.
Route Monitoring
A continuous procedure that checks all signalling conditions of a route and transfers the information towards the entrance signal.
Route Preselection
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 autUntitled1omatically.
Route-Related Locking
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)
Route Release
The release of locked points after the train has cleared the clearing point of a route.
Route Signalling
A signalling system in which the facing point signals indicate the route respectively the direction in which the train is being sent.
Running Line (UK)
British term for a main track.
Running Movement (UK)
British term for a normal train movement under control of a main signal.

S

Safety Points
Points that are installed to provide flank protection.
Schedule
The designation of train description, day, route, speed, arrival and departure times of a train.
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.
Searchlight Signal
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.
Secondary Delay
Another term for collateral delay.
Secondary Tracks (US)
North American term for tracks that are not used for regular train movements.
Section Signal (UK)
British Untitled...1....term for a signal that governs train movements to leave station limits.
Selective Overlap
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.
Selective Protective Points, Dual Protective Points
A flank points that may receive flank protection requests for both positions at the same time. See also: Subsequent Flank Protection
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.
Semaphore Signal
A signal that gives the indication by the position of movable arms or disks.
Semi-Automatic Signal
A controlled signal that my be switched into automatic mode.
Shared Overlaps
Two or more overlaps simultanously leading into the same track section without producing a route conflict.
Shunting
Movements other than train movements accomplished at restricted speed within designated limits for making up trains, moving vehicles between tracks and similar purposes.
Shunting Limits
A territory limited by shunting limit boards or other points designated in the operating instructions, where shunting units may enter main tracks. (see also: Yard Limits)
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.
Shunting Unit
An locomotive with or without other vehicles that is authorised to run as a shunting movement.
Shunt Route
A locked route used for shunting movements and signalled by a proceed aspect of a shunting signal .
Siding
  1. North American term for a loop.
  2. Outside of North America, a shunting track that may not be used for regular train movements.
Signal Aspect
The appearance of a lineside signal, as viewed from the direction of an approaching train, or the appearance of a cab signal.
Signal Box (UK)
British term for an interlocking station.
Signal Cabin
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.
Signal-Controlled Operation
A form of operation in which train movements are governed by signal indication.
Signaled DTC
A form of DTC in which the line is equipped with a simplified signalling system as a safety overlay.
Signaled Operation
A form of operation in which train movements are governed by signal indication.
Signaled TWC
A form of TWC in which the line is equipped with a simplified signalling system as a safety overlay.
Signal Headway
The headway that results from the blocking times of two successive trains in one single block section.
Signal Indication
The information that is given by a signal aspect.
Signaller (UK)
British term for an operator who is in charge of authorising train movements.
Simulation
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
A track layout that combines a crossing with two pairs of points to provide slip connections at one side of the crossing.
Single Slip Switch (US)
North American Term for a single slip.
Slip Switch (US)
North American Term for a crossing that is combined with movable points for slip connections.
Special Conflicting Routes
Conflicting routes that do not differ in the position of points. (see also: Plain Conflicting Routes)
Speed Signalling
A signalling system in which the signals indicate the speed not to be exceeded by a train.
Spring Switch
A points that may be passed by trailing point movements in wrong position and returns to normal position under spring load after the passage.
Spur Track, Spur
A short stretch of track diverging from a main or branchline to serve a customer located away from the primary trackage.
Staggered Home Signals
Another term for a signal arrangement in which a home signal is followed by one or more moving-up signals.
Starter Signal (UK)
Old British term for a signal that governs train movements to leave station limits. It is now called a section signal.
Station
  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).
Station Area
An arrangement of station tracks limited by opposing home signals (not used in North American and British signalling).
Station Exit Signal (UK)
A interlocking signal that governs train movements to leave a station track (mainly used outside North America).
Station Limits (UK)
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.
Station Track (UK)
A main track between successive interlocking signals within the same home signal limits (mainly used outside of North America).
Station Yard
Another term for a station area.
Station Traffic Diagram
A diagram that displays the scheduled occupation of the tracks in large stations and interlockings.
Stub Track
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.
Superior Train
A train having precedence over another train.
Swinging Overlap
A form of overlap protection using a conditional crosslock that allows switching the overlap into another track without cancelling the route.
Switch (US)
North American term for a pair of points. In North American railway operations and signalling turnouts are usually referred to as switches.
Switch Diamond
A diamond crossing with movable frogs.
Switching (US)
North American term for shunting.
Synchronous Simulation
A method to simulate railway operations by modelling all partial processes of the operation in real time sequences. (see also: Asynchronous Simulation)

T

Tabular Interlocking
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.
Target Shooting
A humping control procedure, in which the braking target is the end of the car line in the classification track. (see also: Early Target Shooting)
TCO
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.
Train Resistance
The runnings resistance produced by the running characteristics of the train. (see also: Line Resistance)
Telephone Block
A manual block system in which the occupation of the block sections is controlled by telephone communication between the block operators.
Terminal
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 Locking
An application that will hold a route locked for a specified time after the signal has been manually restored..
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.
Timetable
A document that contains the schedules of all trains of a line.
Timetable And Train Order Operation (US)
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 Authority
The authority to run a train through the network along a pre-defined train path and under operating conditions specified in the timetable. (see also: Movement Authority)
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)
Timetable Capacity
The maximum number of train paths that could be scheduled on a line without considering buffer times.
Token Block System
A block system for single track lines in which the movement authority for a block section depends on the possession 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.
Torpedo
An explosive signalling device, placed on the railhead and detonated by a passing vehicle.
Tower
See: Interlocking Tower
Track Clear Detection
A device that detects the occupation and clearance of a track section.
Track Circuit
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 (UK)
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.
Track Warrant
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.
Traffic Controller (US)
Another term for a dispatcher. This term is used on some railways outside of North America.
Traffic Density
The number of trains that are running at the same time on a certain portion of a line.
Traffic Diagram
A diagram that contains the train paths of all trains that run on a line.
Traffic Energy
The traffic flow multiplied by the average train speed.
Traffic Flow
The number of trains per unit of time.
Trailing Point Movement
A movement on a turnout where the frog faces approaching traffic.
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.
Train Control
The method of authorising train movements.
Train Control Officer
South African term for an operator who is in charge of authorising train movements.
Train describer
A system that identifies trains which occupy a block section on the display at the panel of the operator or dispatcher.
Train Description
A number or an alphanumeric code for identification of a train and its schedule.
Train Director, Train Movement Director
An operator who has full responsibility to issue movement authorities to trains. A train director may supervise a number of levermen.
Train Messages
Messages exchanged between the operators of locally controlled stations for train movement control.
Train Message System
An European form of train control in which local operators exchange train messages.
Train Order
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 Path
A time-distance graph that represents the schedule of a train in a traffic diagram.
Train Register Book
British term for a train record.
Train Record
A written sheet in which an operator records all train movements and train messages.
Train Route
A locked route for the safe passage of a train through an interlocking. (see also: Main Route, Shunt Route)
Yard Movement Trainsheet
A document in which the dispatcher records all train movements and movement authorities.
Trip Stop
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.
Turnout
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.
TWC
Abbr. To Track Warrant Control
Two-Way Working
An operating mode for double track lines where the tracks may be operated in both directions under block signal control.

U

Yard Movement Unsignalled Operation
Another term for a non-signalled operation.

V

Virtual Block System
A block system, in which virtual block sections are established in the control computer without having physical block sections on the line. (see also: Moving Block System)

W

Waiting Time Diagram
A diagram displaying the waiting time as a function of the traffic flow.
Warner Route (UK)
British term for a train route with a reduced overlap. A warner route is Yard Movement governed by an approach controlled signal that will only clear after the train has passed a warning aspects at the signal in rear.
Yard Movement WYE
A triangle track arrangement consisting of three turnouts or of two turnouts and a high angle crossing.

Y

Yard
  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)
Yard Engine (US)
North American term fo a locomotive in yard service that may occupy main tracks only within yard limits.
Yard Limits
  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.
Yard Movement
A movement in a yard or within yard limits for shunting purposes.