Signalling Intro Flashcards
Principle of most signalling systems?
One train in one section at one time
What is it called when more than one train is allowed in a section?
Permissive working
Types of signalling systems (3 answers)
Track circuit block
Absolute block system
Axle counter
Two examples of how trains can be detected by Signallers
Axle counters
Track circuits
3 types of colour light signalling
LED 2 aspect
4 Aspect
3 Aspect
Which signal can split up an AB section ?
Intermediate block home signal
Definition of a controlled signal
Operated by the Signaller , some of which may be set by the Signaller to work automatically
Meaning of a proceed aspect on a semaphore shunting signal?
Proceed at caution as far as the line is clear being prepared to stop at any obstruction, the next signal or buffer stop
What else could be indicated when you receive a cleared subsidiary semaphore signal? (2 answers)
C for calling on S for shunt ahead
What else may be associated with colour light flashing yellow signals ?
PRI preliminary route indicator
If a PRI is not lit what does it mean?
The signal is at danger
What is a single track referred to ?
One train working line
Two ways of controlling a single working line?
Token
Tokenless track circuit system
