Scotrail 334 becomes uncoupled near Uphall (26/11)

[Class385]

Seems tonight at Uphall a 6 car 334 arrived at the station and has somehow become uncoupled and the leading 3 car continued on to the next stop before the driver realised. No members of staff were available and the passengers onboard egressed onto the platform. Would have thought the emergency brakes would bring the leading set to a stand if the coupling failed.
Images from twitter

 

[MrBurnz]

I just received a phone call to tell me that a train has split (unintentionally) at or around the vicinity of Uphall Station.
Currently there is some disruption & cancellations of trains.
I believe that buses are being laid on.

 

[ld0595]

I've seen a few posts on social media tonight saying that the front three cars of a 334 detached tonight at Uphall on an Edinburgh to Helensburgh service this evening. I won't post links to social media accounts with photos, but they are easy to find from the usual channels.

Apparently passengers were left in the rear unit for half an hour with no onboard staff, no electricity and only got out using the emergency handle. Some people are saying passengers on the front unit were turfed out at Livingston. Seems like a pretty serious incident to me - would be interesting to find out the cause and why it seems that no-one noticed 3 cars were detached before leaving Uphall.

 

[LowLevel]

Oh dear! That'll cause some head scratching!

 

[Deltic1961]

A lot of very unhappy customers and major disruption.

My favourite tweet .....

"On the same day NASA have fired a robot off to Mars, Scotrail forgot half a train. The best and worst brains of the planet"

 

[theironroad]

Seems tonight at Uphall a 6 car 334 arrived at the station and has somehow become uncoupled and the leading 3 car continued on to the next stop before the driver realised. No members of staff were available and the passengers onboard egressed onto the platform. Would have thought the emergency brakes would bring the leading set to a stand if the coupling failed.
Images from twitter
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View attachment 55925

Yes, I'd expect the same if all systems were working normally. If for whatever reason the mechanical coupling fails, when the front unit pulls away it should recognise that brake continuity is compromised and make an emergency brake application.

 

[Larry Trapp]

I would assume (and hope) the section would have still shown as occupied and the last signal would have been held at danger ?

 

[MrBurnz]

Would the signal before the station be at red due to the uncoupled train being there? Or would it be green because the other half of the train had already left? I ask because Uphall is a busy little station, & had this happened earlier in the day, would it have caused an accident? Or would the following train been held at a red signal?
Genuinely curious, not a trick question or anything.

 

[Surreytraveller]

I would assume (and hope) the section would have still shown as occupied and the last signal would have been held at danger ?

Should have done. Signaller would probably have assumed that a track circuit failure had occurred in the absence of any other information. I wonder how long it was until the driver realised?

 

[Darandio]

Should have done. Signaller would probably have assumed that a track circuit failure had occurred in the absence of any other information. I wonder how long it was until the driver realised?

OP suggests the next stop.

 

[Ben.A.98]

Would the signal before the station be at red due to the uncoupled train being there? Or would it be green because the other half of the train had already left? I ask because Uphall is a busy little station, & had this happened earlier in the day, would it have caused an accident? Or would the following train been held at a red signal?
Genuinely curious, not a trick question or anything.

Yes the signal would have remained at red, either the track circuit would have remained down or the axle counter would still have a count of 12 on it.

 

[theironroad]

I'm sure someone with the required route knowledge will confirm.

Would the signal before the station be at red due to the uncoupled train being there? Or would it be green because the other half of the train had already left? I ask because Uphall is a busy little station, & had this happened earlier in the day, would it have caused an accident? Or would the following train been held at a red signal?
Genuinely curious, not a trick question or anything.

If track circuited, then would still show occupied but the signaller would beging scratching head as the adjacent section would beoccilied too. If axle counter then obviousky less axles would be counted out compared to in and would show occupied. If old fashioned semaphore block, then front portion wouldn't (or shouldn't ) be hosting a tail lamp so signaller has to assume division of train.

 

[MrBurnz]

Yes the signal would have remained at red, either the track circuit would have remained down or the axle counter would still have a count of 12 on it.

Thanks for the clarification.

 

[lineclear]

Should have done. Signaller would probably have assumed that a track circuit failure had occurred in the absence of any other information. I wonder how long it was until the driver realised?

If the portion of line was track circuited, which I assume this was, a signaller shouldn't assume it's a track circuit failure until the line has been examined.

If this had happened in an AB section, the front portion would not have a tail lamp, so the advance signaller would not allow another train into the section.

 

[Bennski]

Strange how the signalling let the front end of the train continue as far as the next stop since the second half of the train was still occupying the platform section surely there would be something in place to recognise that a train has just left a section but that section is still occupied? Or am I missing something there? And since the platform was still occupied by the rear end of the train that there would be no accident as the signals leading into the platform would be red protecting the platform? And worse comes to worse the next approaching train would be travelling at a speed in-which the driver could stop before he hits the rear end of the train left behind...
First a derailment not long ago and now an accidental uncouple oh dear ScotRail this isnt looking very good...

 

[Larry Trapp]

Seems the service involved was

2H37 1720 Edinburgh to Bathgate
ScotRail service

http://www.realtimetrains.co.uk/train/G90358/2018/11/26/advanced

Edit: Orignally 1720 Edinburgh to Helensburgh Central but changed in RTT after the incident.

 

[Class385]

Strange how the signalling let the front end of the train continue as far as the next stop since the second half of the train was still occupying the platform section surely there would be something in place to recognise that a train has just left a section but that section is still occupied? Or am I missing something there? And since the platform was still occupied by the rear end of the train that there would be no accident as the signals leading into the platform would be red protecting the platform? And worse comes to worse the next approaching train would be travelling at a speed in-which the driver could stop before he hits the rear end of the train left behind...
First a derailment not long ago and now an accidental uncouple oh dear ScotRail this isnt looking very good...

I would hope the signal at the rear would still be at danger and failing that all passenger services call at Uphall so the driver would be going slowly enough to stop.

 

[Bennski]

So the signal at the rear of the platform is red, as well as the signal at the front of the platform. Is there some fail safe in signalling which flags this type of situation as a danger or not?

 

[matt]

So the signal at the rear of the platform is red, as well as the signal at the front of the platform. Is there some fail safe in signalling which flags this type of situation as a danger or not?

The section would still show as occupied so the signal prior to the station would stay at red.

 

[jamesst]

I would hope the signal at the rear would still be at danger and failing that all passenger services call at Uphall so the driver would be going slowly enough to stop.

As explained above the previous stop signal would still be showing a red aspect as the track circuit/axle counter would still be showing occupied regardless of the fact half the train has left.
Whilst rare it isn't unheard of for trains to divide for whatever reason and the rest portion doesn't just disappear from the signalling system

 

[theironroad]

So the signal at the rear of the platform is red, as well as the signal at the front of the platform. Is there some fail safe in signalling which flags this type of situation as a danger or not?

Railway signalling is all failsafe in normal working.

While the train was occupying the signal section then no other train will be allowed to enter under normal working so there is no safety issue.

 

[Surreytraveller]

Strange how the signalling let the front end of the train continue as far as the next stop since the second half of the train was still occupying the platform section surely there would be something in place to recognise that a train has just left a section but that section is still occupied? Or am I missing something there? And since the platform was still occupied by the rear end of the train that there would be no accident as the signals leading into the platform would be red protecting the platform? And worse comes to worse the next approaching train would be travelling at a speed in-which the driver could stop before he hits the rear end of the train left behind...
First a derailment not long ago and now an accidental uncouple oh dear ScotRail this isnt looking very good...

The track ahead of the train would have been clear, so no reason for the signal to stop the train. Unless the signaller had been informed of the division

 

[Tomnick]

So the signal at the rear of the platform is red, as well as the signal at the front of the platform. Is there some fail safe in signalling which flags this type of situation as a danger or not?

No, because it isn’t a danger. The rear portion is protected by a signal in rear of it. The front portion is protected by a signal in rear of it. It’s no different to, e.g., having a second train drop into the platform whilst the first is still in the next signal section.

 

[Bennski]

Right ok, thank you all for clearing that up. Any idea what may of cause this perhaps? Or is it all still up in the air?

 

[Surreytraveller]

Railway signalling is all failsafe in normal working.

While the train was occupying the signal section then no other train will be allowed to enter under normal working so there is no safety issue.

The main danger would have been for a following train to have been asked to examine the line, and the driver of that train proceeding at an inappropriate speed

 

[MrBurnz]

How are the 334's coupled up?
Is it electronically locked once coupled together? I.e...does the driver have button to couple/un -couple the train? If so, is it possible that the wrong button was pressed when setting off? Sorry for all the questions, I don't have an in depth knowledge of the in's & outs of coupling a train.

 

[Surreytraveller]

Right ok, thank you all for clearing that up. Any idea what may of cause this perhaps? Or is it all still up in the air?

I imagine the train probably wasn't attached properly in the first place. If it was, the emergency brakes would have been applied.
It would be unusual for several things otherwise to go wrong - a coupler failed; automatic brake failed (although it appears to have worked in the rear unit)

 

[theironroad]

The main danger would have been for a following train to have been asked to examine the line, and the driver of that train proceeding at an inappropriate speed

...and why would they be travelling at an "inappropriate speed" when proceeding at a suitable speed and being prepared to stop short of any obstruction is rules 101?

 

[a_c_skinner]

If a unit has track circuit actuators and, like the rear unit of this train, loses all power will it still actuate the track circuits?

Similarly in an AB area how assiduously do signallers look for red lights? I know the answer should be yes, but it is the sort of vigilance that humans are not always good at - routine vigilance against the very rare event.

 

[Class385]

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