AWS Flashcards
What does AWS stand for
Automatic warning system
What is the purpose of AWS
The original purpose was to give the driver an audible and visual indication weather the next distant signal was clear or at caution.
What track equipment is associated with AWS
Track equipment consists of an AWS magnet that is normally 180 metres on the approach to a signal
This can vary depending on how fast or slow trains are permitted to travel.
How far before the signal is the AWS track magnet usually positioned.
The magnet that is normally 180 metres on the approach to a signal
This can vary depending on how fast or slow trains are permitted to travel.
Are AWS magnets used at semaphore stop signals
No, only at semaphore distant signals
Where would the AWS magnet be positioned if the permissible speed over 60mph needed to be reduced by more than a third
The AWS magnet would be provided 180 metres away from the speed warning indicator
What else can AWS be used to warn drivers of
Level crossing warning boards or indicators
Temporary speed restrictions warning boards
Emergency speed restrictions warning boards and emergency indicators
What are the 5 types of AWS magnet used.
Permanent magnet, when passed over gives an AWS warning to the driver
Electromagnet, when passed gives the driver a “clear” indication when approaching a green signal
Suppressor magnet, used to suppress permanent magnets when not required
Depot test magnet, used in the depot to test AWS system
Portable magnet, used to give a warning to the driver on approach to temporary and emergency speed restrictions
What on train AWS equipment is there
The receiver, located under the train to detect the sequence and polarities of magnetic fields from AWS track magnets
Audible indicator, gives a bell sound if clear or horn sound as a warning
Visual indicator, an all black indicator when black you have green aspect
AWS/TPWS button, this is used to acknowledge an AWS audible warning.
If not pressed with in 2-3 seconds the emergency brakes will apply
What does a start and finish of AWS gap sign look like
Start of AWS gap is, white circle with black AWS with Red Cross over it
End of AWS gap is, white square with black AWS on it
What do the start and end AWS signs look like if AWS is not provided in the wrong direction on a bi directional line
Start of section is, white diamond with black AWS crossed in red
End of section is, white diamond with black AWS
If an AWS magnet isn’t suppressed a cancelling indicator is provided to advise the driver the AWS warning doesn’t apply to trains in that direction. What to these indicators look like
Where AWS magnet is permanently installed the sign is a blue square with white cross
Where the AWS magnet is temporary the sign is a yellow square with black cross
If you don’t cancel the AWS warning in time the emergency brakes will come on. If this occurs what must you do
Bring the train to a stop
Secure it
Call the signaller
What must you do if you notice a fault with the AWS (bell instead of horn, no warning when approaching a signal at danger, visual indicator didn’t change to yellow and black)
Stop the train immediately and report fault to the signaller
A train must not enter service from the depot if the AWS is…
Defective, the AWS is isolated, or the seal is broken on an AWS isolating hsndle
