Semaphore / AB Signalling Flashcards
What’s the area between the Distant signal and the Home signal called?
Serviceable braking distance.
What’s the back of a semaphore signal look like?
White background with either a black line (back of home/section) or black chevron (back of distant)
What’s a distant signal look like?
Fishtail board, yellow background, black chevron.
What’s a home/section signal look like?
Red background, with a solid white line.
What’s the area between the home signal and the section signal called?
Station limits.
What would you find before a distant signal and how far before?
AWS magnet / 180m
What stops signals being pulled in the wrong sequence?
Interlock
Where is the “Block Section”?
Between a section signal and the next home signal. Unless there’s an Intermediate Block signal then the block section would be between the IBS and next home signal.
How many home signals can there be?
4
Why is there sometimes more than 1 home signal?
To break up station limits into smaller sections to allow more trains at once into station limits.
What does IBS stand for?
Intermediate Block Signal
How do you identify an IBS?
Signal plate with a black vertical line.
Who controls the IBS?
The signal box before it.
What is an IBS made up of?
1 distant signal, 1 stop signal.
What does a white “diamond” <=> on a signal indicate and where would you find one?
The signal is track circuited, usually on a Home signal. (So the signaller knows you’re there.)
What’s the little semaphore signal (sometimes found below a normal signal) called?
Semaphore subsidiary signal.
What does a horizontal semaphore subsidiary signal mean?
Obey main signal
What does a cleared semaphore subsidiary signal authorise a driver to do?
Pass the main signal at danger and proceed at caution towards…
1. The next train
2. Signal
3. Buffer stop
And be prepared to stop short of any obstruction.
Sometimes semaphore subsidiary signals have a letter in a round circle below them. What are the letters and what do they mean?
C = Calling On
S = Shunt Ahead
What does proceeding at caution mean?
Being able to stop safely before..
1. Obstruction
2. Train
3. Signal
4. Buffer stop
What must you do if you get a semaphore shunt signal that has cleared?
Proceed at caution as far as the line is clear.
When might you see a distant board?
On approach to…
1. A colour light stop signal
2. A semaphore stop signal
3. A stop board
4. A points indicator
5. A buffer stop
What is a Fringe Box?
An area where coloured light signals change to semaphore signals, so Absolute Block rules apply.
What must you do when moving over points worked from a signal box where there is no signal associated with them?
You must get the signallers permission make sure they are clamped and check the points fit correctly.
How will a signaller in a signal box give permission to cross over points?
- Verbally
- Arm raises above head (daytime)
- White light moved quickly twisting wrist
Once cleared of points, if no shunter with you, advise signaller by one short blast of the horn.
What must you do when you’re detained at a signal?
Set DRA and put brake into full service.
What identifies a co-acting signal
A plate with “CA”
