Signals Flashcards
What do 3 position signals indicate? (2)
permissible speed, and
give advance information about the next signal ahead.
What is a Distant signal?
A fixed signal located outside a home signal at a station equipped with two position signals.
What is a Home signal?
Provided where necessary to govern entry into a station or junction.
What is an Outer Home signal?
Governs entry into a station and located in advance of a home signal. Provided in situations where station limits are extended from the home signal.
What is a Starting signal?
Controls the entrance of trains to the section ahead where movements are signalled in one direction. Where specified in S&I diagrams, three position colour light shunting signals will also be used as starting signals.
What is a Directing signal?
They are used in station limits to direct trains to the various platforms, sidings, or positions to which the signals apply and protect those lines to which they apply. Where specified in S&I diagrams, three position colour light shunting signals will also be used as directing signals.
What is a shunting signal?
Controls the passage of trains and shunting movements within station limits. Where shunting signals are provided, they must be used for shunting movements.
What is a departure signal?
Controls the entry into a block section where movements are signalled in both directions.
What is an approach signal?
They may be provided where it is necessary to control the speed of trains approaching junctions, points, or other interlocked areas. An approach signal is an absolute signal placed in the rear of another absolute signal.
What is an intermediate signal?
Where necessary, in ASR areas, divide the line into shorter sections and control the entry of trains into such sections. These signals may also be provided approaching a station and within station limits where the station is equipped with three position signals.
What are the 3 classes of signals
Absolute
Permissive
Departure
What speed is low speed?
not exceeding 25km/h able to stop short of any obstruction
What is medium speed
not exceeding 25km/h unless a speed board/ dynamic speed indicator/ ETCS authorises a higher speed
What is restricted speed?
not exceeding 40km/h and able to stop clear of half the distance of clear line ahead
What is normal speed?
not exceeding the maximum speed for the locality
What aspect is always on top for a medium speed incation?
red on top of either yellow or green
When are R lights used?
drop tracks
assisting a disabled train in the following direction
train stacking
blacked out/imperfectly displayed signal
When are A lights used?
track may be occupied or obstructed
rail may be broken or displaced
LX alarms may not be working
When is a low speed used?
when the track may be occupied or obstructed
e.g. drop tracks, coupling, double berthing/stacking
What does a horizontal aspect on a BI repeat?
red aspect
what does a 45 degree aspect on a BI repeat?
yellow aspect
what does a vertical aspect on a BI repeat?
green aspect
