Railway Glossary
Definitions of common railway infrastructure and engineering terms.
- Axle Counter
- A device at the end of a track section that counts the number of train wheels passing over it to determine if the section is clear.
- Ballast
- Crushed stone used to provide a stable, draining bed for railway sleepers and track.
- Block Section
- A defined section of track that, under normal conditions, only one train may occupy at a time.
- Bogie
- A chassis or framework carrying wheels, attached to a train, allowing negotiation of curves.
- Cant (Superelevation)
- The raising of the outer rail on a curve to allow trains to negotiate the curve at higher speeds safely.
- Catenary
- The system of overhead wires used to supply electricity to a locomotive, pantograph, or tram.
- Control Centre
- A facility where signallers manage the routing and movement of trains over a wide area.
- Crossover
- A pair of switches that connects two parallel railway tracks, allowing a train to change tracks.
- Derailer
- A safety device used to prevent unauthorized movements of trains from fouling a main line.
- ETCS
- European Train Control System; a modern digital signalling and train protection system.
- Fishplate
- A metal plate bolted to the ends of two rails to join them together in jointed track.
- Formation
- The prepared surface of the ground upon which the track ballast is laid.
- Headway
- The time or distance interval between two trains travelling in the same direction on the same track.
- Interlocking
- An arrangement of signal apparatus that prevents conflicting movements through an arrangement of tracks such as junctions or crossings.
- Level Crossing
- An intersection where a railway line crosses a road or path at the same level.
- Loading Gauge
- The maximum physical dimensions (height and width) that a railway vehicle can be to safely clear lineside structures.
- Overhead Line Equipment (OLE)
- The physical wires, structures, and insulators that deliver electricity to trains.
- Pantograph
- An apparatus mounted on the roof of an electric train to collect power through contact with an overhead line.
- Platform
- A raised area alongside a track providing safe access for passengers boarding and alighting trains.
- Points (Switches)
- The movable sections of track that guide a train from one track to another.
- RRI
- Route Relay Interlocking; a signalling system using electro-magnetic relays for logic.
- Signal
- A mechanical or electrical device erected beside a railway line to pass information relating to the state of the line ahead.
- Sleeper (Tie)
- A rectangular object used as a base for railway tracks, maintaining the correct gauge.
- Subgrade
- The native soil underneath a constructed railway formation.
- Third Rail
- A method of providing electric power to a railway train through a semi-continuous rigid conductor placed alongside or between the rails of a railway track.
- Track Circuit
- An electrical circuit spanning a section of track to detect the presence or absence of a train.
- Track Gauge
- The specified perpendicular distance between the inside faces of the two rails of a railway track.
- Treadle
- A mechanical or electrical device attached to the rail which is actuated by the flange of a passing train wheel.
- Turnout
- The complete assembly of a switch and crossing, permitting a train to pass from one track to another.
- Wayleave
- A right of way granted by a landowner, generally for purposes such as access for railway maintenance.