AWS/TPWS

Question 1

How long do you have to acknowledge the AWS warning after hearing the horn sound?

Answer 1

2.7 seconds.

Question 2

How far away from a signal is the AWS magnet normally placed?

Answer 2

200 yards/183 metres, although it may be positioned at a greater distance on high-speed lines or a lesser distance on lower speed and platform lines.

Question 3

When will the AWS visual indicator appear?

Answer 3

The visual indicator serves as a reminder to the driver that they have acknowledged an AWS warning, therefore it will only appear once the AWS reset button has been pressed.

Question 4

What will the AWS do when the train is approaching a proceed signal?

Answer 4

The bell will sound (the driver does not have to acknowledge this) and the visual indicator will remain black.

Question 5

What will the AWS do when the train is approaching a caution or danger signal?

Answer 5

The horn will sound and the driver will have 2.7 seconds to acknowledge this by pressing the AWS reset button. The visual indicator will then display a black and yellow ‘sunflower’.

Question 6

What will happen if you have previously acknowledged an AWS warning and you subsequently receive another?

Answer 6

The visual indicator will revert to black and you must re-acknowledge the AWS horn before it will display a ‘sunflower’ again.

Question 7

Which indication will each of the AWS magnets give?

Answer 7

When a signal is green, electricity will flow to the electromagnet, which will give a bell sound. If the electromagnet is de-energised, the permanent magnet will sound a horn warning.

Question 8

Where on the train are the AWS and TPWS receivers located?

Answer 8

At the centre of the free bogie.

Question 9

What does this sign mean?

Answer 9

This is a cancelling indicator sign. It means that the AWS magnets haven’t been suppressed but that the warning indication doesn’t apply to trains travelling in that direction.

Question 10

How far away after an AWS magnet is a cancelling indicator sign normally placed?

Answer 10

200 yards/183 metres (minimum of 50 yards/45 metres).

Question 11

Give an example of a right side failure within AWS?

Answer 11

When the AWS magnet sounds a warning horn but the signal is clear. This is a fail safe as it encourages the driver to be more alert and risk aware.

Question 12

Give an example of a wrong side failure within AWS?

Answer 12

When the AWS magnet sounds a bell but the signal is at caution or danger. This is a wrong side failure as it increases risk by indicating to the driver that they can proceed, despite them needing to be prepared to stop.

Question 13

What should you do if you are in a track circuit block signalling area and the AWS horn sounds but the signal is clear?

Answer 13

Accept the signal’s indication but report the fault at the first opportunity using the RT3185 form.

Question 14

What should you do if you are in an absolute block signalling area and the AWS horn sounds but the signal is clear?

Answer 14

Treat the signal as being at caution and expect to stop at the next signal as it may be experiencing a mechanical failure. You must report it at the first opportunity using the RT3185 form.

Question 15

What is the fault code for an AWS magnet that produces neither a horn nor bell sound when the train passes over it?

Answer 15

7

Question 16

What is the fault code for an AWS magnet that produces a bell sound when the signal in advance is displaying a caution or danger aspect?

Answer 16

5

Question 17

What should you do if the AWS bell sounds (or the AWS makes no sound) but the signal is at caution or danger?

Answer 17

This is a wrong side failure. Stop immediately and report the fault using RT3185.

Question 18

What should you do if you are driving in poor visibility and receive an AWS warning horn but reach the signal and it is green?

Answer 18

The signal may have been yellow when your train passed over the AWS magnet and subsequently changed to green, however you should contact the signaller to check if a right side failure has occurred.

Question 19

What does this sign mean?

Answer 19

This sign indicates the start of an AWS gap where AWS is not provided at a station on a line equipped with AWS.

Question 20

What does this sign mean?

Answer 20

This sign indicates the start of the relevant section of line concerned when AWS is not provided in the wrong direction on a bi-directional line.

Question 21

What does this sign mean?

Answer 21

This sign indicates the end of an AWS gap where AWS is not provided at a station on a line equipped with AWS.

Question 22

What does this sign mean?

Answer 22

This sign indicates the end of the relevant section of line concerned when AWS is not provided in the wrong direction on a bi-directional line.

Question 23

What should you do if you fail to acknowledge the AWS warning horn in time?

Answer 23

1. Put the emergency brakes on.
2. Press the AWS reset button.
3. Call the signaller and duty control manager.

Question 24

What will happen if you don’t acknowledge the AWS warning horn within 2.7 seconds?

Answer 24

The brakes will apply, the brake demand light will flash and a 60 second timer will start.

If the AWS reset button is pressed within 60 seconds, the brake demand light will stop flashing (but remain illuminated). It will extinguish and you will regain brake release once 60 seconds is up.

If the AWS reset button pressed after the 60 seconds is up, the brake demand light will extinguish and brake release will return immediately.

Question 25

What does TPWS activation mean?

Answer 25

When the driver applies the emergency brake before the TPWS has intervened due to one of the following: • Train approaches TPWS equipped signal too fast • Train approaches speed restrictions too fast • Train approaches buffer stops too fast • Train passes a TPWS equipped signal at danger • A fault has occurred with the TPWS equipment or receiver.

Question 26

What does TPWS intervention mean?

Answer 26

When the TPWS intervenes and applies the brakes on the unit as the train is travelling too fast (or there is a fault with the TPWS equipment or receiver) without the driver initiating the brake application.

Question 27

What is the fault code when the TPWS fails to activate?

Answer 27

16

Question 28

What is the maximum speed you can travel at when the AWS has been isolated?

Answer 28

• Line speed if there is a competent person. • 60mph if there is no competent person. • 40mph in poor visibility regardless of whether a competent person is provided to assist or not.

Question 29

What must you do if the TPWS intervenes when you are approaching buffer stops?

Answer 29

1. Acknowledge the TPWS brake demand. 2. Give 2-2 on the bell buzzer to prevent the guard opening the doors and passengers alighting whilst the train hasn’t entirely reached the platform. 3. Once the train has come to a stop, move forward to the normal stopping point if safe to do so. 4. Inform the signaller what has happened. 5. Carry out the instructions given by the signaller.

Question 30

When are the TPWS loops live?

Answer 30

Only when the associated signal is at danger.

Question 31

What is the Train Stop Override button and when should you use it?

Answer 31

The TSO temporarily isolates the TPWS for 20 seconds and is used when you are required to pass a signal at danger. It illuminates a steady yellow when operated and extinguishes once the train passes over the TSS.

Question 32

When would AWS track equipment not be provided at a station?

Answer 32

When the permitted speed is 30mph or less and the layout is complex.

Question 33

What do AWS magnets alert the driver to?

Answer 33

• Signals at caution or danger. • Level crossing boards or indicators. • Temporary speed restriction warning boards. • Emergency speed restriction warning boards and emergency indicators.

Question 34

What is a suppressor magnet used for?

Answer 34

To suppress permanent AWS magnets when they’re not required to apply to a train movement (e.g. magnets applicable to the opposite direction on a single or bi-directional line).

Question 35

What does it mean when the AWS isolation/fault indicator is flashing?

Answer 35

A fault has been detected in the train’s AWS equipment.

Question 36

What does it mean when the AWS isolation/fault indicator is steady?

Answer 36

The train’s AWS equipment has been isolated.

Question 37

What does it mean when the AWS isolation/fault indicator is unlit?

Answer 37

The AWS is normal.

Question 38

What is the purpose of TPWS?

Answer 38

To stop the train if it has: • passed a signal at danger without authority • approached a signal at danger too fast • approached a reduction in permissible speed too fast • approaches buffer stops too fast. It is not designed to prevent SPADs but to prevent a train that has had a SPAD from reaching a conflict point ahead of the signal.

Question 39

What is the overspeed sensor system and how does it work?

Answer 39

The overspeed sensor system (OSS) comprises two transmitters: the arming loop and the trigger loop. Once the train passes over the arming loop, a timer is started and if the train passes the trigger loop within that time, the TPWS will initiate a brake demand.

Question 40

Where is TPWS provided?

Answer 40

• On passenger lines at all main running signals capable of showing a stop aspect which protect crossing or converging movements. • At stop signals where conflicting movements could take place in the overlap of the next stop signal ahead. • On the approach to buffer stops at the end of passenger platforms. • On the approach to permissible speed reductions, where the speed on approach is 60mph or more and the reduction is at least one third.

Question 41

How far from buffer stops are TPWS equipment placed?

Answer 41

65 metres/70 yards.

Question 42

What speed will trigger the TPWS approaching buffer stops?

Answer 42

10mph.

Question 43

What does TPWS track equipment consist of?

Answer 43

The train stop system (TSS) and the overspeed sensor system (OSS).

Question 44

When is the TSS energised? When is it de-energised?

Answer 44

The TSS is energised when the signal is at danger, and de-energised when the signal is showing a proceed aspect.

Question 45

What does the OSS comprise of?

Answer 45

The arming loop and the trigger loop.

Question 46

What does it mean when the temporary TPWS isolation/fault indicator is unlit?

Answer 46

The TPWS is normal.

Question 47

What does it mean when the temporary TPWS isolation/fault indicator is flashing?

Answer 47

A fault has been detected in the train’s TPWS equipment, or the start-up test has not been completed successfully.

Question 48

What does it mean when the temporary TPWS isolation/fault indicator is illuminated steadily?

Answer 48

The train’s TPWS equipment has been temporarily isolated.