That's because it's a control log that is constantly updated and is also why it's not for public consumption. That information was what was believed to be correct at the time by the person providing it. It is immediately overtaken by events. Hence it is a pain when people take it upon themselves to release it to the press because quite often the initial report, on further investigation, isn't correct.
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Collision and derailment near Salisbury (Fisherton Tunnel) 31/10/21
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That's because it's a control log that is constantly updated and is also why it's not for public consumption. That information was what was believed to be correct at the time by the person providing it. It is immediately overtaken by events. Hence it is a pain when people take it upon themselves to release it to the press because quite often the initial report, on further investigation, isn't correct.
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Gloster
Veteran Member
To a certain extent, whether the GWR unit was moving or stopped is irrelevant. As an aside, in the days of the 31 hauled Portsmouth-Bristols many drivers would come round the curve on the Romsey line at a moderate pace and then accelerate as the locos reached the tunnel. Whatever, it seems that the GWR train was where it should had every right to be and had, unless something very peculiar has occurred, been correctly signalled.
It is how the London got to the position it got to that is probably going to be the question. Again, unless something very peculiar happened to the signalling, it should have had a yellow on the approach to Laverstock North Junction and a red on the approach to Tunnel Junction, both with restrictive AWS warnings (or the equivalent if isn’t AWS anymore).
If the GWR was stopped by part of the tunnel roof falling in or some other obstruction, that is a separate question. However, the reports are still so confused that whether the train stopped before being hit or was proceeding normally is not clear. Even if it did stop, the reason might be entirely unrelated to any other matter. For example, and this is a pure EXAMPLE, the driver might have slightly misjudged the braking as the train came up to the points.
It is how the London got to the position it got to that is probably going to be the question. Again, unless something very peculiar happened to the signalling, it should have had a yellow on the approach to Laverstock North Junction and a red on the approach to Tunnel Junction, both with restrictive AWS warnings (or the equivalent if isn’t AWS anymore).
If the GWR was stopped by part of the tunnel roof falling in or some other obstruction, that is a separate question. However, the reports are still so confused that whether the train stopped before being hit or was proceeding normally is not clear. Even if it did stop, the reason might be entirely unrelated to any other matter. For example, and this is a pure EXAMPLE, the driver might have slightly misjudged the braking as the train came up to the points.
I used the phrase in inverted commas, someone higher up the thread had used the term.
norbitonflyer
Established Member
Don't forget there was a third train in the area. A route couldn't be set for the SWR (1L53) until 1F27 (Bristol to Southampton) had cleared the junction as it was routed across the SWR train's path. Even if a route had been set as soon as 1F27 cleared the junction (1841.75, according to RTT) that only gives 45 seconds (from the SWR's recorded time at Laverstock North Junction) for it to get to Tunnel Junction from a standing start (as it wouldn't have had a a proceed aspect until the route was set)
I wondered about that, however I gather that online train describer derived apps were showing that the GW train had the route. Also the timetable batting order is for the GW train to arrive at Salisbury first to give a decent Exeter connection off it. Also a train to Southampton had apparently passed through the tunnel shortly before the incident making it more probable that the route from Romsey to Salisbury was set (avoiding potential conflict through the junction) whether or not signals had been cleared for a Romsey to Salisbury movement.
Obviously at least one of those trains should not have passed the protecting signal and entered the junction but as yet we have no idea what aspects (if any) were showing at the signals proeecting the junction and importantly what aspects were showing on the next signal in rear (protecting the junction with the laverstock chord) when the train from Waterloo passed over it.
Until that information is known we can't really speculate with any credibility as to the root cause. We need to know which holes appeared in which cheeses.
Until then just give thanks that the train to Southampton didn't depart a few minutes later otherwise yesterday would have been as dark a day for Salisbury as 1st July 1906.
Gloster
Veteran Member
Regarding the comment about the possibility of the GWR having slid past a signal: the curve leading up to the points is very sharp and there is another sharp curve at Milford a short way before. In between the two is a straight stretch with a signal that would have been at yellow if that protecting the junction had been at red. For the GWR to have slid past the protecting signal and keep going on a 20 mph restricted curve as far as the tunnel would have been quite a feat.
43096
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Given that 1F27 had only just passed over the junction, which should have held SY31 at red for 1L53, it seems highly unlikely that 1F27 would have cleared the section, released the interlocking, allowed the road to be set for 1L53, SY31 cleared and 1L53 to have accelerated over the junction (given it should have been approaching SY31 at danger).
The most likely scenario is 1F30 has the road over the junction, 1L53 has passed SY31 for whatever reason and collided with 1F30.
Last night was lucky; it could have been a lot worse had 1L53 been a little earlier and ended up hitting 1F27, with 1F30 running into the wreckage.
I don’t think any conclusion should be made by anyone other than the RAIB, but they haven’t even released their report about the crash at Kirkby over 6 months ago. I think we can get a reasonably good idea what could’ve happened in the mean time though.
But I don’t believe they hit each other head on while moving. If they did, would this be because the GWR train was travelling at 20mph over the junction coming from Southampton while the SWR train was travelling at line speed from Basingstoke? If the SWR train hit the GWR train just before it had cleared the junction with its last carriage still on the Southampton lines that could result in them coming to rest in a way that is consistent with the pictures we have seen and explain why the driver of the GWR train did not contact the signaller before the collision, but would have required either a catastrophic failure of the signalling system or a SPAD to have occurred.
I think it was a 4 car 158 wasn’t it, but if it had split in the middle then they would have to have evacuated using the end doors at each end.
I think this is the best post we’ve had in this thread all day. Whether the it was moving or not, the SWR unit definitely hit it (or vice versa).
But of course something very peculiar has occurred or the 2 trains would not have ended up in this situation and what now needs to be determined is what exactly this very peculiar occurrence was and what caused it.
bengley
Established Member
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It's more likely that the SWR has slid past the signal seeing as it's the SWR which doesn't appear to have the route set for it.
Yes I’ve put my speculating hat back into my speculating hat drawer and I’ll purely be reading with interest things from those that know more than me from now on.
I think this forum has too many people willing to jump on others for whatever reason.Yes I’ve put my speculating hat back into my speculating hat drawer and I’ll purely be reading with interest things from those that know more than me from now on.
The person you responded to posted a postulation, he didn't say it *had* happened but said it *could have* happened. Thats fair comment and adds value to the thread. Like you, earlier in the day I was considering it as a distinct possibility before it was pointed out to me for the reasons I stated in my post that it was a most unlikely scecario.
Had said poster claimed it had happened or had probably happened that would be a different matter.
bramling
Veteran Member
Reality is a major incident has happened, and naturally lots of people are going to be curious as to how it happened, especially somewhere like this forum where lots of people use trains, and perhaps in some cases anxieties or concerns which a sensible discussion can put to rest.
As long as the discussion is informed, which most of this thread has been, and no one attempts to dress their thoughts up as facts, which as far as I can see no one has, there doesn't need to be issue.
A sensible and measured discourse is greatly preferable to some of the sensationalist stuff we see on media outlets when these sorts of incidents happen.
All we know is that it passed the signal. What aspect if any was showing, the reason it was passed and whether it was legitimately passed is not known.
Is there any history of rail adhesion issues in the area?, it seems odd to me that rail adhesion issues would have manifested so suddenly while trains were using the track all day (rather than, say, the first trains of the day after an overnight autumn storm).
silverfoxcc
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Watching Paul C;lifton on BBC south just now he said that the SWR train was going so fast that 7 carriages of it ended up in the tunnel.
Was it an 8 car set up?
Was it an 8 car set up?
It looks like 3 (just 159102) in all of the photos I’ve seen.
Is he confusing the two trains because they look similar?
Bacon_BMW
Member
There was 7 carriages total (4 on the GWR, 3 on the SWR), and not all of them were in the tunnel. Seems like he was either misinformed, or just wrong.
Well said @ bramling.
I'd also like to vote a big thumbs up for the mods who have steered an even course on this since Sunday night and wisely, after a little tidy up, kept the thread open - serving nearly 600 viewers as I write.
DerekC
Established Member
Some accidents are simple and have an obvious primary cause. This one isn't and doesn't. Trying out theories is all very well, but there is no way you are all going to know exactly what happened until RAIB makes an initial report. Let's just be thankful for modern (and not quite so modern) rolling stock design and a goodish slice of luck which meant that the consequences of this accident were nowhere near as bad as they might have been.
D365
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Agree wholly with both posts.
And also this. All too easy to speculate (myself included) when there is no immediate conclusion to jump to.
This thread is indeed illustrating that the sequence of events and factors that culminated in this incident could be somewhat complex and not what may first seem apparent.
Agree with your post but we don't actually know that this one isn't and dosen't. As things stand it *could* have had a very simple cause.
Most of the early statements including official sources have been contradicted by later official statements issued today, either explicitly or implicitly.
All we know is that at least one of those trains should not have crossed that junction at that time but that both did!
bramling
Veteran Member
This pretty much applies to every accident, especially the bigger ones. Just thinking back a few years:
Clapham - issues with working practices
Cowden - multiple factors which due to the limitations of the time the role each may have played was never quite fully resolved
Watford - an "interesting" setup where boundaries were pushed to make the layout fit the standards, driver with history of incidents
Southall - train kept running with defective AWS which no one seemed too bothered about
Ladbroke Grove - significant signal sighting issues, inexperienced driver with deficient training
Hatfield - management of a known engineering issue proved inadequate
Potters Bar - privatisation maintenance organisation proved inadequate
Chancery Lane - management of a known engineering issue proved inadequate
Whatever happened yesterday, it'd be unusual for their not to be a complex set of factors which have come together.
Eccles1983
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No it's not.
A train stopped out of course is not drummed into anyone to immediately place protection.
If you think you are foul, or have derailed then yes, if the signaller cannot protect you. (TBW/ESW excluded) But for stopping out of course? No.
swt_passenger
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I think last night for quite a while after the incident RTT (as an example in post #70) was still showing the SWR train as a 9 car. This was subsequently changed, I think someone said there’d been alterations during the day that hadn’t filtered through to open data sources...
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trainmania100
Established Member
Do hope I'm not asking a stupid (or already explained) question here as there's already 600 posts and I'm on a break
ITV meridian news showed a Google Earth animation of the crash. It appeared (to me at least) to show, both trains running in the same direction, but on adjacent lines.
The right train derailed middle coach inside the tunnel, and the left train came alongside it from behind, also in the same direction. And hit the front coach which was in the middle of the line
Did they get their report wrong, or do trains actually run in either direction, on both tracks inside the tunnel? Not something I've often seen, a train running wrong line unless turning back on a signal ...
Or maybe the animation was just for the ordinary Joe and wasn't intended to represent what actually happened...
ITV meridian news showed a Google Earth animation of the crash. It appeared (to me at least) to show, both trains running in the same direction, but on adjacent lines.
The right train derailed middle coach inside the tunnel, and the left train came alongside it from behind, also in the same direction. And hit the front coach which was in the middle of the line
Did they get their report wrong, or do trains actually run in either direction, on both tracks inside the tunnel? Not something I've often seen, a train running wrong line unless turning back on a signal ...
Or maybe the animation was just for the ordinary Joe and wasn't intended to represent what actually happened...
Well said. Aren’t the 158s about the most modern design BR came up with?
swt_passenger
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The animation is wrong, both services would have used the same line (the down line) through the tunnel, the GWR first, then the SWR. Post #17 shows the idea..,
bramling
Veteran Member
The latter. There is no bi-directional working. What appears to have happened is the front of the SWR train has run into the side of the GWR train on Salisbury Tunnel Junction. Thankfully the SWR train was deflected to the right, and momentum has carried it onwards whilst the remaining energy was dissipated. It is this deflection to the right which has made it appear to enter the tunnel "wrong line", in reality it was simply moving in a derailed state so could have ended up anywhere.
As has been posted before, it is very fortunate no vehicles seem to have collided or got trapped up against the tunnel portal. Some fractional differences in timing or position could have led to a very different outcome.
== Doublepost prevention - post automatically merged: ==
There is some awful stuff doing the rounds in the media at the moment. Sky are still reporting that the first train was derailed, and there is at least one anonymous "expert" who claims to be a Network Rail whistleblower who is alleging a serious failure with a mythical safety system which is supposed to "kick in". Probably just as well there's other stuff in the news at the moment or else this sort of nonsense would be getting more air-time.
millemille
Member
Localised low adhesion can develop very quickly, irrespective of time of day, and leaf fall related adhesion worsens with the passing of a number of trains over freshly fallen leaves (it is the compacted leaves that produce the very sticky black substance on the railhead that is the cause of low adhesion) until it reaches a low and then gradually improves as more trains pass over it.
it is also worth considering that if the train/trains in question were braking where preceding trains hadn't then any low adhesion for the previous trains wouldn't have been an issue, or if the train/trains in question were braking harder - exceeding the available co-efficient of friction of the contaminated rail - than preceding trains had braked - not exceeding the available co-efficient of friction - then again it wouldn't have been an issue.
It can even be something as prosaic as preceding trains running on a different part of the railhead due to differences in bogie/primary suspension/wheel arrangement and then the train/trains in question running a different, uncleaned, part of the railhead (as happened back in 2019 at the Norwich road level crossing near miss).
Indeed so. South Today running with the idea that the SWR could have spadded, not been able to brake in time due to the weather or could have been speeding. Nothing like some good old Media speculation to stir things up - having turned into experts on all things Policing, they now seem to have overnight turned into experts on Railway management (Bangs head against the wall).
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