Network Signalling Flashcards
What is rail Principle 2?
Rail vehicles must maintain safe separation via an appropriate method of signalling and/or operation.
Define Station Limits?
Includes all lines within the outermost signals or points on each line controlled by the signaller for the station, or as otherwise defined on S&I diagrams.
Define a Block Section?
A single section of line between the limits of two adjoining interlocked stations / junctions in either a single or multiple line area. The Block Section will permit movements in either both directions or one direction only.
Describe a Low Speed light and where it is attached to a signal mast?
When illuminated, low speed lights display a short range steady yellow light when at proceed. The lamps of low speed lights are backed by a white triangular metal plate with a yellow border.
They are attached directly below the light units of an absolute signal.
Describe a Restricted Speed light?
When illuminated Restricted speed lights display a short range steady white ‘R’ light when at proceed.
The lamps of restricted speed lights are backed by an orange square metal plate with a white border.
Describe an ‘A’ light?
Displays an illuminated letter ‘A’, visible at short range. ‘A’ lights are backed by a triangular metal plate painted black with a white border when at proceed.
Double unit signals with two multi aspect or two searchlight units (or a mixture of both) are provided where and for what reason?
- where one or more lines diverge from the main line
- at junctions
- at locations where a reduction to medium speed is required
- at locations approaching a signal where a reduction to medium speed is required
What do three position colour light signals indicate?
- Permissible speed, or
- Gives advance information about the next signal ahead
Define an
Outer Home Signal
Governs entry into a station and located in advance of a home signal.
Same as Home Signal but in advance of it.
Define a
Home Signal
Provided where necessary to govern entry into a station or junction.
Define a
Directing Signal
They are used in station limits to direct rail vehicles to the various platforms, sidings, or positions to which the signals apply and protect those lines to which they apply.
Define a
Departure Signal
Controls entry into a Block Section where movements are signalled in both directions.
Define a
Shunting Signal
Controls the passage of rail vehicles and shunting movements within station limits.
Define an
Intermediate Signal
Provided in Block sections to divide the line into shorter sections and control the entry of rail vehicles into such sections.
Name the three types of colour light Shunt Signals?
- Two-position colour light shunting signals
- Three-position colour light shunting signals
- Yellow low-speed light signals on a fixed signal mast
