Dictionary
Alphabetical list of signalling terms and a short explanation.
A
Aspect - signal aspect.
ATB - The Dutch train protection system, developed in the 1950s. Based on the American Pulse Code Cab Signaling. The system is basic and only protects five speeds. There has been developed more extensions to ATB, such as ATB+ and ATB-Vv. Wikipedia.
ATC - Automatic Train Control, a general class of train protection systems for railways that includes speed control in addition to signal detection. List of ATC systems
ATP (Aarhus Letbane) - A simple version of ETCS Level 1, used to control speed and prevent passing signals showing the Stop aspect.
AWS - Automatic Warning System, British system warning the driver of restrictive signals. See more
B
Balise - electromagnetic device near the tracks that transmits signal information wirelessly to the train.
Block post - a signal box where a block signal is managed by a human.
BOStrab - German light rail, metro and tram regulations. Wikipedia
C
Cab Signalling - information about movement authority and speed limits are presented to the driver in the cab. For example ETCS.
CBTC - a railway signaling system that makes use of telecommunications between the train and track equipment for traffic management and infrastructure control. Wikipedia
C-APT - a former signalling system implemented along the British WCML for use alongside the Advanced Passenger Train. Wikipedia
D
E
ERTMS - European Rail Traffic Management System, a system of standards for the managing and interoperation of European railways. Wikipedia
ETCS - European Train Control System, the signalling component of ERTMS, a Positive Train Control system. Wikipedia
F
G
H
I
Interlocking - a system that prevents points from moving when a signal path has been set. It can work electronically or mechanically.
J
K
L
LZB/ Linienzugbeeinflussung is a more advanced signaling system compared to PZB, and is mostly used on high-speed lines.
P
Points also switch, turnout. A mechanical installation enabling railway trains to be guided from one track to another, such as at a railway junction or where a spur or siding branches off. Wikipedia
Positive Train Control a general term for a train protection system that prevents movement without permission. For example ETCS.
PZB/Punktförmige Zugbeeinflussung is the basic, most used train protection system in Germany.
Q
R
S
Station - definition varies by country. See individual pages for each country.
Switch also point, turnout. A mechanical installation enabling railway trains to be guided from one track to another, such as at a railway junction or where a spur or siding branches off. Wikipedia
Switchback also Zig Zag. A method of climbing and descending steep gradients, where shallow-gradient track reverses direction for a while, and then reverses again to continue in the original direction.
T
Token - a token is used to ensure only one train is on a track segment at one point in time. Mostly replaced by electronic signal systems.
Track Circuit is a way of detecting trains by sending a small electrical signal along the tracks and detecting the presence of a train electrically. One of the most common train detection systems in use today. Wikipedia
Track Warrant - an instruction authorizing the staff of a train to perform specific train movements.
Train Order - part of Train Order Operation, a mostly obsolete method of managing trains. Wikipedia
Trainset - a set of wagons permanently coupled together to form one unit, see also Multiple Unit
Treadle - a mechanical device that detects the passage of a vehicle at a specific location. Not to be confused with an axle counter.
Turnout also point, switch. A mechanical installation enabling railway trains to be guided from one track to another, such as at a railway junction or where a spur or siding branches off. Wikipedia
Turntable - a piece of track which is possible to rotate horizontally such that a locomotive or a wagon can be reversed or moved onto tracks radiating out from the turntable.
U
V
Vacuum brake - a brake system that uses a vacuum to release brakes and atmospheric air pressure to apply the brakes from the driver's position. Today mostly superseded by the air brake
W
Wayside objects, wayobjects - objects part of the railway infrastructure besides the tracks. Signals, signs, overhead lines, support poles, platforms, barriers, among other things.
Wheel Slip - loss of adhesion of the wheel on the track. May lead to flat spots on the wheel surface. Can be caused by slippery tracks.
Wheeltapper - a railway worker employed to check the condition of certain train components by tapping on them. Most often axle boxes and brake pads.
Westinghouse Air Brake - Invented in 1869, it used air pressure to apply the brakes directly from the locomotive. A predecessor to modern day air brake systems.
Whistle - used to warn the sorroundings or to communicate with other train staff. Modern vehicle almost all use a horn instead.
Wrong-side failure - a failure that puts the system in an unsafe state, as opposed to “Right-side failure” or “Fail-to-safe”. Wikipedia
X
Y
Yard - an arrangement of tracks where rolling stock is shunted to and from trains, cargo is loaded and unloaded, and where rolling stock can be parked.