AWS/TPWS CB

[greatmasterp]

Hi. What are drivers actions if the AWS/TPWS circuit breaker trips in the leading cab, and will not reset?

 

[Da142072]

My understanding as a (now retired) guard is that the driver should bring the train to a stop immediately (providing that it will not be across a junction, magnet etc.) and contact the controlling signaller who will liaise with the TOC's control.

If a suitable competent person such as a guard is available they may be asked to travel in the front cab with the driver to the next staffed station where the train will be taken out of service.

Possibly a current driver may be able to confirm or expand on this, as I think there is some form filling required.

 

[Supercoss]

Advise the controlling signaller, Shut down the driving desk and key out. Reset MCB.
Do walk of shame to rear cab, key in, contact signaller for permission to draw forward a few feet, move a few feet , contact signaller , change ends
Key in and set up desk, contact signaller train is now ready, tell no-one you stopped over an AWS magnet.
If fault still present obey company instructions, do not move train advise signaller and await “DOTE” reply from company control for defective on train equipment.

 

[skyhigh]

tell no-one you stopped over an AWS magnet .

I have never known the AWS circuit breaker to trip because you stopped over a magnet. A horn you can't cancel, definitely, but never a trip? What class of train does that?

 

[D365]

My understanding as a (now retired) guard is that the driver should bring the train to a stop immediately (providing that it will not be across a junction, magnet etc.) and contact the controlling signaller who will liaise with the TOC's control.

If the AWS/TPWS circuit breaker is tripped, the train will bring itself to a stop due to loss of supply to the brake circuit.

 

[DJP78]

Drivers actions are to report to signaller. Attempt resetting of the MCB on phone to fleet maintenance team.

If cannot be reset, isolation of AWS / TPWS with permission from fleet maintenance team and then proceed to a station where train is taken out of service.

Speed restrictions might apply depending on visibility, day / night etc and whether a competent person is brought into the cab to act as second pair of eyes, but this person must be driver competent due to the AWS / TPWS being signalling specific.

DSD / Vigilance can be guard or driver as this is not concerned with signalling.

 

[DJP78]

If the MCB couldn’t be reset at all and the train still couldn’t be moved even with AWS / TPWS isolated, set would probably be rescued with the effected cab being buried in the middle.

Desperate measures might be change ends and wrong direction move under signaller instruction to emergency crossover and back to nearest station, alight passengers and again take train out of service.

 

[Paul AC]

If the AWS/TPWS circuit breaker is tripped, the train will bring itself to a stop due to loss of supply to the brake circuit.

Indeed, though in more general terms the train brake will be immediately applied just as if an AWS/TPWS penalty brake application had occurred; though in this case there will be no indications on the TPWS Control Panel as the power for this is taken from the same Power Supply Unit that powers the AWS/TPWS Control Unit.

If this happens it will not be obvious what has caused the brake application, especially if the MCB is not easily visible - which of course depends on the train type. Some Train Management Systems might well monitor the state of the MCB (by checking if there is a voltage on the Load side terminal) and give a suitable fault indication to the driver. When the driver has found the tripped MCB, resetting it and powering up the AWS/TPWS is going to take a little time.

If the MCB won't reset, the driver will have to use the Full Isolation Switch (or equivalent term) to obtain brake release, then follow company instructions - usually to run at reduced speed and detrain passengers at the first opportunity.

 

[Nym]

Not to be overly boring on this, but the answer lies initially in GE/RT8000 (Rule Book) TW1 Section 1 Abnormal Brake Applications.

This then lies in Para.2 which states you must immediately contact the signaller.

Then after this, you're into Defective On Train Equipment guidance from your company in combination with instruction from the signaller.

Regardless of if there is an indication or not from any of the TPWS systems, be it AWS or TPS, if TPWS "was the reason the train was brought to a stand"

You'll then likely be needing an RT3185 for Signal/AWS/TPWS/ERTMS/ATP/TVM failure or irregularity, even though RS522 doesn't have a code for "Rolling Stock Failure" it would be pertinent to complete one anyway.

Next... and this is the fun one.

If the train has been designed in line with the design guidelines for certain manufacturers' Enhanced TPWS (those who know, will know.) then there's a chance that with a tripped MCB, you'll be going nowhere, permanently. Due to how the guidelines require the system integrator to configure the "TPWS Full Isolation Switch" (That makes it not an isolation switch.), there is a probability that certain failure modes will result in permanent disablement and needing to wind off the brakes and be recovered.

== Doublepost prevention - post automatically merged: 26 Jul 2026 ==

If the AWS/TPWS circuit breaker is tripped, the train will bring itself to a stop due to loss of supply to the brake circuit.

Should...

 

[greatmasterp]

My question wasn't formed clearly, you all was right with procedures. What i was looking for was how to move the train after, and after my own research agree with Paul AC you need fully Isolation of AWS/TPWS to be able to move your train again.
Thank you all. Thats answer my question, so we can close the topic. BTW unit is 150/1
Thanks

== Doublepost prevention - post automatically merged: 26 Jul 2026 ==

Indeed, though in more general terms the train brake will be immediately applied just as if an AWS/TPWS penalty brake application had occurred; though in this case there will be no indications on the TPWS Control Panel as the power for this is taken from the same Power Supply Unit that powers the AWS/TPWS Control Unit.

If this happens it will not be obvious what has caused the brake application, especially if the MCB is not easily visible - which of course depends on the train type. Some Train Management Systems might well monitor the state of the MCB (by checking if there is a voltage on the Load side terminal) and give a suitable fault indication to the driver. When the driver has found the tripped MCB, resetting it and powering up the AWS/TPWS is going to take a little time.

If the MCB won't reset, the driver will have to use the Full Isolation Switch (or equivalent term) to obtain brake release, then follow company instructions - usually to run at reduced speed and detrain passengers at the first opportunity.

Agree, thank you for this.

 

[800301]

If the AWS/TPWS circuit breaker is tripped, the train will bring itself to a stop due to loss of supply to the brake circuit.

Not in a Class 165/6