Collision and derailment near Salisbury (Fisherton Tunnel) 31/10/21

[bramling]

What might happen to the 159 and 158 involved, will the damaged vehicles be scrapped or is there a chance ( a very tiny one seeing the photos ) they could be repaired?

Don't think anyone can really answer that question yet. There certainly appears to be a fair bit of damage to at least two vehicles.

 

[Sprinter158]

That will be for the insurers to decide. If the repair costs exceed the unit value, then they will write it off. The unit will become the property of the insurers. The 'railway' could buy it back from the insurers.

Thanks for explaining

 

[Ianno87]

Don't think anyone can really answer that question yet. There certainly appears to be a fair bit of damage to at least two vehicles.

It's also unclear whether they can sensibly be re-railed in the tunnel or whether it'll be a cut up on site job.

 

[JN114]

I would still query where the information that there were 2 158's involved has come from, or that they have split? Given the number of photos available and taken from within the tunnel, it is at least mildly surprising that no photos of this other unit have appeared.

So where's the other half of the GWR train? The other two 158 vehicles?

They are in the tunnel, behind the photographer.

The photos from within the tunnel of 158763 show the gangway “made up” - inferring it was coupled and the forces in the incident have caused the train to divide.

 

[Annetts key]

It didn't happen at Clapham Junction in 1988. In that incident a false feed to a track circuit allowed trains to briefly disappear from the system, allowing the signals protecting that section to clear, reverting to red as the train reached the overlap circuit beyond. Until one driver saw the signal go from yellow to red in front of him and stopped at the next signal to report it - unbeknown to him meaning his train was standing in the unprotected section. Had there been an "out of sequence" alert this would have been spotted as soon as trains started running that morning, insteadof not beiung noticed until trains were close enough together that they were running on double- yellows

The problem at Clapham was not the track circuits, they were working as designed and correctly. The problem was due to the redundant wire that had not been properly disconnected at both ends (only one end had been disconnected, the other end was still connected to the power supply) or removed or properly insulated at the removed end. That got disturbed and moved and the uninsulated end touched a terminal and hence bypassed the contacts of that track circuit relay. Hence even when the section was occupied and the track circuit relay was de-energised, the signal control relay was being powered via the old redundant wire. This is also why the signaller did not notice the problem.

Is it possible that the points approaching the tunnel portal moved as the first train moved over them, and so what was "hit" was actually pointwork?

Yes, it’s possible. Part of the mechanism may have failed or broken. The interlocking is designed to prevent power reaching the motor with a train in section. And the points are designed to not move unless under power or manually operated. But it’s a mechanical (and maybe a hydraulic) system, and if not properly maintained, this failure mode is possible. Unlikely to derail the train, as it’s a trailing point.

I saw in one photograph that the track is somewhat moved/deformed near the diamond. Presumably as a result of the collision. Would it be possible that the point ends on the up line could have moved as a result of the collision and so do not reliably indicate any route set just prior to the collision ?.

Again possible. Who knows how much force was transferred to this point and what effect this had. However, it looks the the point operating mechanism is a clamp lock. They normally will not unlock and move unless under power or manually pumped. Of course, there is nothing normal about the force that they were subjected to. But if they had moved, often the switch rails end up in the middle, with the points not set one way or the other.

From the BTP statement:

I would expect an official BTP statement to be very precise in its wording and there a clear implication in it that the GWR train hit the SWR train - and not the other way around which so far most people seem to have been suggesting. (Note: if you aren’t certain which train hit which, the correct wording would be ‘… a Great Western Railway service from Southampton to Cardiff and a South Western Railway service from London to Honiton collided…’)

I would not take the BTP statement as absolute fact in terms of what hit what. IMHO they are just trying to say that two trains collided. It is up for the formal investigation to work out what happened.

As said before, the investigation report will hopefully be able to answer these questions once it is published.

 

[Bletchleyite]

The photos from within the tunnel of 158763 show the gangway “made up” - inferring it was coupled and the forces in the incident have caused the train to divide.

I'd assumed the gangway was open because of people being evacuated that way due to the side doors being shoved against the tunnel wall on one side and having another unit shoved against them on the other.

 

[Ken H]

Luck.

Roger Ford in Modern railways often stated 'Railway accidents are the combination of Murphys law and Soddes law. if anything can go wrong it will, and at the worst possible time. Loads of rail accidents have been made worse by another train hitting the wreckage of a previous incident/accident.

On the subject of GSM. Should it work in tunnels? If not, how far into a tunnel does it penetrate? Is this tunnel long enough to have created a black spot. And can a guard in the rear cab press the 'panic' button if he feels its warrantied?

 

[quattromatt]

Roger Ford in Modern railways often stated 'Railway accidents are the combination of Murphys law and Soddes law. if anything can go wrong it will, and at the worst possible time. Loads of rail accidents have been made worse by another train hitting the wreckage of a previous incident/accident.

On the subject of GSM. Should it work in tunnels? If not, how far into a tunnel does it penetrate? Is this tunnel long enough to have created a black spot. And can a guard in the rear cab press the 'panic' button if he feels its warrantied?

GSM-R doesn’t have a “panic” button.

 

[westcoaster]

The protection issue has been latched on because its in the rulebook, in these days of gsmr it's a last resort.

Where was the rec call to the signaller.

Why didn't the signaller stop all trains.

If no rec call was made why?.

If the gsmr was out why was it out?

These are the questions that will need to be answered.

again if the trains collided, most of these points are muted, how would the GWR driver know of the collision?
he could have initiated a gsmr rec call ( for all he knew he could have derailed or units split).
Again protection would be the same as above.

I'm sure I saw pics of the rear of the gwr unit, with white lights on last night. ( that indicates someone did go back to switch them on

 

[skyhigh]

My word! How on Earth did the passengers in the middle coach of the SW Turbo escape catastrophic injury?

Slightly picky maybe, but no Turbos were involved in the incident. It was only 158/159s.

 

[Signal Head]

Do we know if there is point to point locking between points 105 and 106?

Things we know:
A GWR train (1F27 16:58 Bristol Parkway to Portsmouth Harbour) had left Salisbury at about 18:37 on the Up Main just before the incident. Going through the tunnel and crossing over the junction onto the Up Dean, but it stopped before it got to Dean.

GWR train (1F30 17:08 Portsmouth Harbour to Bristol Temple Meads) passed Dean (on the Down Dean line) at about 13:35, and approached the junction (Tunnel Junction), but for some reason stopped over the junction on the Down Main, with the rear part still on the junction, but with the front part in the tunnel. The front part does not look to be derailed in the photos.

We do not know why this train stopped, but drivers don’t stop their trains in a such a location without there being a good reason.

SWT train (1L53 1720 London Waterloo to Honiton) was in the area of Andover at 18:29 on the Down Main, it continued on towards Tunnel Junction and hit GWR train 1F30 at the junction where the Down Main and Down Dean converge. The collision resulted in it derailing and some of the units ending up at an angle. The leading cab suffering extensive damage.

The public live train websites (which obtain their feed via a Network Rail system that in turn gets some of its information from the various Train Describer systems) show the ‘head code’ (TD ‘number’) for 1L53 still in the ‘berth’ for signal SY31.

Questions (I not looking for answers, just things to think about, the kinds of questions that the investigators will be asking, so please don’t speculate here):

What was the reason that caused the driver of GWR train 1F30 to stop their train where they did? Did it actually hit something? Was there a problem with the points fittings (point number 106) ? Or was there a problem with the train? If this train did hit something or if there was a problem with 106 points, did this train derail?

Why did the TD not step the ‘head code’ forward for 1L53 when the train has clearly passed signal SY31?

If there was no problem with GWR train 1F30 operating the track circuits (where it is in the photos I would expect it to be on at least two track circuits) the interlocking should have held signal SY31 at red. So was there a problem with the track circuits?

In the photos, points 105 look to be lying reverse, as they would have been needed for the move of 1F27 over the junction. This is the opposite way to that required for 1L53 if there is point to point locking between points 105 and 106. We don’t know which way points 106 are because we can’t see them and they may be under the GWR train. If there is point to point locking, then if points 105 are not set correctly, signal SY31 should not clear. Was there a problem here?

Did the signaller route signal SY31? If the answer is no, then signal SY31 should not clear to a proceed aspect. Did signal SY31 stay red? Was it lit? What was the sighting like? Could approaching train drives see it clearly and at the required minimum distance?

If SY31 does not show an proceed aspect or if the signal is not illuminated , then the AWS should result in the AWS horn sounding in the leading cab of train 1L53. Was the track and lineside equipment for the AWS working? Was the train AWS equipment working?

SY31 should be fitted with TPWS equipment. The TPWS transmitter loops should be energised at all times unless the signal is showing a proceed aspect. Was the track and lineside equipment for the TPWS working? Was the train TPWS equipment working?

The signal, SY31 requires electricity to work, as does the TPWS. Was there a loss of power to this equipment, causing SY31 to go ‘black’ and disappear into the darkness? The signal identification plate/sign should be made of the reflective type so that it can be seen more easily in poor light conditions. Was it? Was it clean?

If there was a loss of power due to a fault with the signalling system, what caused this?

If there were no faults with the signalling system, was there a problem with the braking system on train 1L53? Or was there rail head contamination that reduced the effectiveness of the braking system?

I’m sure there are many other questions. As I said earlier, please don’t speculate. The facts will come out in the report once the investigation is complete.

Point to point locking doesn't matter in this instance (and the presence of ERSE (or its later equivalent) makes me think it's likely not to be provided).

Even without point to point though, security of interlocking is provided by the route to point locking, and that will (or at least should/needs to) be provided.

So route SY31 will require 105N and 106R. The initial calling is done by ERSE, but the locking and proving is in the relay interlocking.

All the lack of point to point locking means is that, if you are working points on the keys, it would be possible to have both sets Reverse at the same time, but you still cannot achieve that state by setting routes.

 

[RPI]

Slightly picky maybe, but no Turbos were involved in the incident. It was only 158/159s.

The 159's were referred to as South West Turbos when new

 

[JN114]

I'd assumed the gangway was open because of people being evacuated that way due to the side doors being shoved against the tunnel wall on one side and having another unit shoved against them on the other.

If you were evacuating, you wouldn’t take the time to carefully make up the gangway, secure all the doors away etc, they’d just be flung open and get out. Also given the headlights on the significantly more damaged 159 are still illuminated I’d expect the same on the 158 had it been leading.

I'm sure I saw pics of the rear of the gwr unit, with white lights on last night. ( that indicates someone did go back to switch them on

The header picture on the BBC site last night at some point had the SWR unit displaying hazard signal on rear; I believe it was shared upthread.

 

[bengley]

One of the photographs I have seen taken from the scene is of the railhead in the area and shows quite severe leaf fall contamination - I suspect that the very fact this photo has been taken suggests that the railhead conditions may be a suspected cause of the incident.

https://i.imgur.com/cd9XSp5.png

 

[westcoaster]

I would still query where the information that there were 2 158's involved has come from, or that they have split? Given the number of photos available and taken from within the tunnel, it is at least mildly surprising that no photos of this other unit have appeared.

they did on the initial bbc report you could see the leading GWR 158 with Hazard warning lights activated.

 

[Flange Squeal]

My instinct says that if I were the signaller I would give priority to SWR given the long single track sections it had ahead of it towards Honiton.

Most SWR Honiton services were being terminated short at Salisbury anyway due to flooding blocking the West of England line, so letting the GWR go in front so it could be in and out of Salisbury probably did make sense, rather than delay both the Bristol and Portsmouth GWRs for a train that was possibly about to terminate anyway.

 

[507020]

If you were evacuating, you wouldn’t take the time to carefully make up the gangway, secure all the doors away etc, they’d just be flung open and get out. Also given the headlights on the significantly more damaged 159 are still illuminated I’d expect the same on the 158 had it been leading.

But if you’re evacuating in a tunnel and the doors on both sides are obstructed because you’re wedged between the tunnel wall and the other unit that’s hit you, what’s flung open as quickly as possible is still the gangway door isn’t it? Lucky it wasn’t a non-gangway 165/166 or evacuation would have been a lot harder.

 

[800001]

again if the trains collided, most of these points are muted, how would the GWR driver know of the collision?
he could have initiated a gsmr rec call ( for all he knew he could have derailed or units split).
Again protection would be the same as above.

I'm sure I saw pics of the rear of the gwr unit, with white lights on last night. ( that indicates someone did go back to switch them on

Yeah I saw a video with the Gwr units rear lights flashing

 

[Dan G]

My word! How on Earth did the passengers in the middle coach of the SW Turbo escape catastrophic injury?

It didn't hit anything (beyond coming to rest against the tunnel wall). The cab of the 159 hit one of the 158 cars; that appears to be the only contact between the two trains.

What's lucky is that there doesn't seem to have been anyone sitting right at the point at which the 158 was struck.

PS I'm very disinclined to believe there's a second 158 involved. Surely a second unit would have had its brakes on, as no doubt the visible unit would have had? It could not have moved on into the tunnel with the impulse from the 159, having broken open the coupling.

 

[norbitonflyer]

Looking at the photos, the impression I got is that the GWR hit the SWR.

Most people seem to have understood the opposite to be the case, but it is possible that both were moving at the moment of collision, so they came intoi sidelong collision at the junction. This is not inconsistent with reports that the GWR train stopped because it hit something/was derailed in the tunnel - if that "something" was the SWR train.

 

[HamworthyGoods]

Slightly picky maybe, but no Turbos were involved in the incident. It was only 158/159s.

To be picky back - 159s have always been called South Western Turbos, 158s are Express Sprinters. 165s and 166s are Networker Turbos.

Class 159

www.southwesternrailway.com

The 159's were referred to as South West Turbos when new

They still are! ^^

 

[Ken H]

...

As said before, the investigation report will hopefully be able to answer these questions once it is published.

I thought that if there was a general point affecting rail safety they could issue an interim warning, so changes to equipment/procedures could be made before the final report.

 

[Sir Felix Pole]

Given that the GWR units have divided, that would imply that they were in motion - the side swipe and derailment of the rear coach bringing it to an abrupt stop and parting the couplings. BTP have also suggested that the GWR train did not hit a obstacle.

 

[norbitonflyer]

It didn't hit anything (beyond coming to rest against the tunnel wall). The cab of the 159 hit one of the 158 cars; that appears to be the only contact between the two trains.

What's lucky is that there doesn't seem to have been anyone sitting right at the point at which the 158 was struck.

PS I'm very disinclined to believe there's a second 158 involved. Surely a second unit would have had its brakes on, as no doubt the visible unit would have had? It could not have moved on into the tunnel with the impulse from the 159, having broken open the coupling.

Even with the brakes applying, it might have rolled considerably further than the derailed unit before stopping if it was still on the rails.

 

[Annetts key]

BBC TV today showed the GWR with it’s white lights flashing.

 

[jfollows]

It is still not clear whether the Bristol train had stopped in the tunnel before it was hit by the SWR one, and if so, why.

Whilst I agree that the precise facts aren't known, RTT shows 1F30 as having passed Dean late at 18:35.5 and, if that's correct, 1F30 would only have had time to reach Tunnel Junction at 18:42 when the accident occurred (and, in particular, it couldn't have arrived and stopped at 18:38 which I recall was reported in the paper). I'm sure that the Daily Mail's story about it waiting for 5+ minutes can't be correct in any way (EDIT "Around 50 people were stranded on the derailed train for seven minutes before a South Western Railway service from London to Honiton with around 50 more people on board ploughed into the stationary train at around 6.45pm." as others have noted also). My thinking is that both trains were moving at the time of the collision, and that 1F30 was first to arrive at the same place.
Why this happened is obviously going to generate speculation but will doubtless come out in due course.
I think others have alluded similarly to reported timing and the inaccuracy of the Daily Mail but the paper report was produced many hours ago, before some of the information became clearer.

EDIT But I'm guessing about many things here, of course.

 

[Falcon1200]

Initial reports stated, as per Post #46:

The GWR train struck an object
The GWR train derailed as a result
This knocked out the signalling
Therefore the SWR train collided with the GWR train

Now it appears that none of these statements may actually be correct ?

Hopefully the RAIB will publish an initial report as soon as possible.

 

[Ken H]

GSM-R doesn’t have a “panic” button.

can the driver not send a general alert message just by pressing a button? If he knew his train was derailed towards another running line? What is the procedure if he suspects his train is fouling another line?

 

[quattromatt]

can the driver not send a general alert message just by pressing a button? If he knew his train was derailed towards another running line? What is the procedure if he suspects his train is fouling another line?

We’re supposed to press the emergency call button and make a railway emergency call, when you press that button all signals in that area are supposed to go to danger, if you can’t get a call through for whatever reason it’s clips and dets and a nice walk.

 

[507020]

Initial reports stated, as per Post #46:

The GWR train struck an object
The GWR train derailed as a result
This knocked out the signalling
Therefore the SWR train collided with the GWR train

Now it appears that none of these statements may actually be correct ?

Hopefully the RAIB will publish an initial report as soon as possible.

But what we can see from pictures of the tunnel entrance is that the rear carriage of the GWR train derailed and hit the tunnel wall and then the SWR train immediately behind it collided with it and was deflected onto the other line coming to rest at a 45 degree angle with the rear carriage still on the rails. This would support the GWR train derailing first but I don’t understand how only the rear carriage can derail and not the front ones and the SWR train shouldn’t have been able to enter an occupied section unless a serious failure of the signalling system occurred.