AWS and TPWS Flashcards
What is the purpose of the AWS?
To provide the driver with an audible and visual indication of upcoming signals.
What two audible cues can be delivered by the AWS?
Bell or warning horn
What does the bell signify?
Proceed signals
What does the warning horn signify?
For danger/caution signals or dangers ahead
What should the audible cue prompt the driver to do?
Look out of the window to identify what the system is warning you about.
Once the driver has identified what the system is warning him about, what must he do?
Acknowledge the warning by pressing the AWS cancellation button.
How long does the driver have to acknowledge the warning by pressing the AWS cancellation button?
3 seconds
How does the train know to deliver an AWS audible cue?
When the train passes over a 2 sided magnet that is located 180m from the signal or danger that the system is warning the driver about. The AWS receiver located underneath the train then receives signal from this magnet.
What are the two sides of the magnet?
The permanent magnet and the electromagnet
What does the permanent magnet do?
Triggers the warning horn
What does the electromagnet do?
Triggers the bell
What will you receive when the electromagnet is energised and the permanent magnet is de-energised?
Bell
What will you receive when the electromagnet is de-energised and the permanent magnet is energised?
Warning horn
What protects AWS in the driving cab?
The AWS circuit breaker
If the AWS circuit breaker is tripped, what will happen to AWS?
It will stop AWS from working.
Is it possible to isolate AWS in the cab? If so, what restrictions will be in place?
Yes but speed restrictions will apply if this is done.
If you are driving alone without the AWS, what is the maximum speed you can travel at?
60mph
If you are driving with a competent person without the AWS, what is the maximum speed you can travel at?
Line Speed
If you are driving alone in fog, what is the maximum speed you can travel at?
40mph
If you are driving with a competent person in fog, what is the maximum speed you can travel at?
40mph
Name 4 pieces of AWS/TPWS in-cab equipment
Horn speaker, cancellation button, sunflower for visual indication, TPWS panel
What might have happened if you receive a warning horn before a signal that is displaying a proceed aspect?
This could be a right side failure or it could be the case that a warning board or emergency indicator is positioned in close proximity to a signal and the AWS warning applies to this and not the signal.
What happens to the AWS magnet where it is positioned ahead of a warning board or emergency indicator?
The permanent magnet is permanently energised and the electromagnet is permanently suppressed so that you will always receive a warning horn for this whilst these boards are in place.
In semaphore signalled areas, which type of semaphore signals will you receive AWS warnings for?
Semaphore distant signals only. Not semaphore stop signals.
Could you receive an AWS warning if a semaphore stop signal and a semaphore distant signal are mounted on the same post?
Yes, but the warning horn or bell will apply to the distant signal and not the stop signal.
Will you receive an AWS warning for a fixed distant signal?
Yes but as these signals never clear, the AWS magnet will always have the permanent magnet energised and the electromagnet suppressed so that you always receive a warning horn for these signals.
What are the requirements of an AWS gap area?
If the location has a line speed of 30mph or under and the layout is considered to be complex, you may not receive AWS warnings.
In an AWS gap area would you receive any AWS warnings?
No, you would not receive any AWS warnings.
If an ESR or TSR is implemented within an AWS gap area, would you receive an AWS warning for this and why?
Yes, you may do if a temporary magnet has been implemented.
What is a depot test magnet?
A permanent magnet used to test the operation of AWS equipment after maintenance has been carried out on it. These are normally located at the exit of certain maintenance depots.
What does a black sunflower indication mean?
The associated signal is showing green aspect.
This may also advise the driver that the audible warning has not been acknowledged- if not acknowledged after 3 seconds, the brakes will apply.
What does a yellow and black sunflower indication mean?
Advises the driver that a warning indication has been acknowledged.
Do you need to acknowledge AWS bells?
No, only warning horns.
Where is the AWS cancellation button usually located?
On the driver’s desk.