Door mechanism failure - Horsley

[whole diary]

[ellendune]

A rare trip into SWT^▸ (South West Trains) land. I was on the 8:58 Guildford to Waterloo as I was travelling to Epsom. We were delayed at Clandon due to problems with the doors.  When we got to Horsley the doors on one coach would not close.  After some delay the train was terminated there. after which the guard went along the train and pressed a button on each carriage which closed all the doors in that carriage - including the one that had failed. The train then departed leaving us all behind in the cold.

We were on an 8 coach train which had barely a single coach full of passengers. Was there no way that the one coach could have been isolated and the rest of us carried in the other half of the train, which was , if I recall, made up of two 4 car units?

[inspector_blakey]

Firstly, you are correct in that the Guildford-Waterloo via Cobham and via Epsom services are almost invariably 8-car trains, formed of two four-car 455 units. They run pretty empty off-peak, but it's a very different story in the peaks.

Difficult to know exactly what the nature of the fault was, but a train wouldn't be terminated and taken out of service unless it really wasn't possible to resolve the door fault in a reasonable amount of time. There is an interlock circuit that won't allow the train brakes to be released unless all doors are proved closed, so doors on one coach remaining open will prevent interlock being achieved and stop the entire train moving. This interlock can be over-ridden in certain circumstances to allow a failed train to move, but that would only be to allow the train to move at limited speed to somewhere where the passengers could be de-trained before it was removed from service. Since this failure occurred at a station it sounds like a sensible decision was made. I don't know if you're suggesting that the train could have been split to allow four cars to carry on, but this wouldn't have been an option as sufficient staff wouldn't have been available to detach the units. Further, given that the service is every 30 minutes via Epsom and every 30 minutes via Cobham, for a frequency of 4 trains an hour, it would have been important to get the failed train out of the way to reduce reactionary delays as far as possible.

As inconvenient as it may have been, sounds to me like this was the correct decision operationally in the circumstances.

[thetrout]

Interesting about the Interlock Override Mechanism.

I did think the mechanism could be overridden. There was a case a while back in 2010 where a Class 315 departed London Liverpool Street with the doors open. It was reported that a passenger once the train started moving got up and closed the doors!!

My personal view and certainly the action I would have taken would have been a PASSCOM activation. The Red Alarm Levers are there for a reason... Use them!

There is a PDF bulletin on the RAIB^▸ (Rail Accident Investigation Branch) website here

[ellendune]

I was just surprised that the doors on one of the two units could not have been locked out while staying in the train, but not in use.

[ChrisB]

Especially as pax^▸ (passengers) could walk through to oter coaches to exit the train

[Network SouthEast]

Rule book says that if two doors in the same carriage are defective then the carriage must be locked out of use. I don't think that class 455s actually have locks on the internal doors to prevent access, which would have made it impossible to lock the coach out of use.

In any case, we don't know the whole story. As Inspector Blakey says, a fault with Interlock is a show stopper for a train, so even if a carriage could have been locked out, the train would still have to be taken out of service anyway.

[ellendune]

I realise we do not have all the facts, but perhaps in future designs/modifications the facility to lock out a carriage would improve overall resilience and availability.