Definitions Flashcards
Block section
A single section of line between the limits of two adjoining interlocked stations / junctions in either single or multi-line area. The Block Section will permit movements in either both directions or one direction only.
Interlocked Station
A station or portion of a station with automatic signalling provided to prevent conflicting movements.
Interlocked Junction
A junction between single and multi-lines or a crossover between multi-lines.
Interlocking
Points and signalling that are electrically or mechanically arranged so as to prevent conflicting train movements from being operated.
Intermediate Section
Any portion of a Block Section divided into two or more intermediate sections. Entrance to subsequent intermediate sections is governed by an Intermediate signal.
Station Limits
Includes all lines within the outer most signals, station entry boards or points on each line controlled by the Signaller for the station.
Note: Where fixed signals are not provided, station limits include all lines within the first facing points or Points Indicator met approaching the station on the main line from either direction or as otherwise defined on S&I diagrams.
Main Line
The principal line.
Branch Line
A secondary line diverging from a more significant Main Line.
Sidings
All lines other than main lines and crossing loops. May be used for marshalling, stabling, loading, and unloading or servicing of rail vehicles.
Blocking
Holding signals at stop or points set to prevent rail movements from entering a section of line
Track Circuit
An electric circuit where current is carried through the rails and used to detect the presence of trains.
Bond Wire
Wire connection between two adjoining rails carrying signalling or traction power.
Axle Counter
A form of train detection equipment provided in place of the conventional track circuit.
The system typically consists of wheel sensors and (electronic) evaluation units for counting axles (technically wheels) of the train both into and out of a section.
The section will remain occupied until the number of axles out equals the number of wheels in, or a reset has been completed by an authorised person.
Points
A mechanical installation enabling rail vehicles to be guided from one track to another, such as at a junction or where a siding branches off. also known as turnout.
Catch Points
Placed on main lines as required to intercept runaway rail vehicles.
Safety Points
Placed on crossing loops and sidings as required to prevent vehicles entering on or fouling the main line. Safety points are also placed on the main line where shown on S&I diagrams.
Trap Points
Single blade derailing switches provided for the protection of the main line, crossing loop, or other places as shown on S&I diagrams.
Signal
A visual display device which conveys instructions, or provides warning of instructions regarding the Operator’s authority to proceed.
Fixed Signal
Colour-light signals classified according to use, are as shown in the Network Signals, Indicators and Boards Manual.
Station Entry Board
Provided in multi-line areas where a signal is not available and defines a boundary for entry into an Interlocked Station.
Block Entry Board
Provided in Multi-line areas where a signal is not available and defines a boundary for entry into a Block Section.
Shunting
To move a rail vehicle into a different location / track using a MPU for this purpose.
Sleepers
A rectangular shaped tie laid perpendicular to the rails which keeps the rails correctly spaced apart and transfers the load it receives from the rail in to the ballast.
Ballast
A layer of crushed stone to form the track bed on which the railway sleepers and track are laid.
