TPWS

Question 1

Name the On track equipment required for TPWS?

Answer 1

Over speed sensor system comprising of arming loop and trigger loop (if travelling too fast to stop at associated signal).
Train stop system comprising of arming loop and trigger loop (if signal is at danger).

Question 2

Name the train equipment required for TPWS?

Answer 2

TPWS receiver under train
In cab Visual Control Panel comprises of -
Brake demand light (red)
Temporary isolation fault light (yellow)
Train stop overide button and light (yellow)

Temporary isolation switch for temporary block working or emergency special working

Question 3

What will happen if you are speeding over an OSS?

Answer 3

Emergency brake application
No noise but flashing brake demand light
Must acknowledge with AWS reset button

Question 4

XXX If an automatic brake application is initiated as a result of TPWS you must?

Answer 4

Ensure the train is brought to a stand
Acknowledge the TPWS brake demand 
Report to signaller 
Follow instructions you are given 
Make no further movement of train until instructed by signaller

Question 5

What is the purpose of the arming loop?f

Answer 5

When signal is displaying stop signal the arming loop becomes energised
As train passes over arming loop a timer starts. This is used to determine how long it takes the train to reach the trigger loop and can then determine the speed of the train.
Will apply emergency brake application if necessary.
Psr and buffer stop arming loop always on.
Signals arming loop on at danger

Question 6

What is the purpose of the trigger loop?

Answer 6

When signal is at danger.
If train reaches trigger loop within a set time will activate and apply emergency brake.
Brake demand will be lit in cab.
No noise but must be acknowledged.

Question 7

What does a flashing yellow light on visual control panel indicate?

Answer 7

There is a fault with the TPWS equipment in that cab.
Driver Must try to rectify by either shutting down the desk, isolating the system. This must not be done without authority from signaller.

Question 8

What does the train overide button do when pressed?

Answer 8

If authorised to pass a signal at danger you should operate the train overide button.
Button will illuminate yellow.
Approximately 20 seconds to allow you to pass one signal at danger.

Question 9

If TPWS develops a fault you must?

Answer 9

Stop the train immediately
Report the circumstances to the signaller
Do not move the train until instructed to do so
Act in accordance with the instructions you are given
Complete RT3185