Report of collision Bedford (Elstow) - 19/06/26

[mandub]

It's possible the lead driver just couldn't cancel his AWS & so the brakes dumped on. I've had that happen though obv on older traction.

 

[Purple Train]

Firstly, I hope that all those injured in this terrible incident make a full recovery, and my prayers are with those injured, and with the family, friends, and colleagues of Driver Burton.

For a rear-end collision at 50mph, particularly one where the stationary train appears to have had its brakes hard on, I think the 810 in particular has held up reasonably well. No doubt there will be factors to consider to improve crashworthiness, but it doesn't seem like it'll be a major negative based on current reports. The emergency response, and press/recovery response from the industry, seemed exemplary and reflected very well on all parties in spite of the tragic circumstances.

I have a whole heap of questions which only RAIB can answer. A key piece of information is what AWS indication(s) the 360 driver received.

It seems to me that he clearly wasn’t expecting the red signal to be red - when on restrictives, you just do not chase the red at 76mph. So, did he get bell vice horn, nothing vice horn?

RAIB will look at the sun angles to see if there’s a chance of misreading due to sun illumination.

They’ll also look at whether there was a potential read across to the adjacent signal on the slows.

They’ll look at his training records. Any prior incidents and Competence Development Plans arising.

They’ll look at possible driver fatigue - rostering etc.

There are many possibilities, not limited to the above. I urge all to remember that the Swiss cheese model is real - incidents of this nature rarely have a single point of failure…

I await the RAIB’s further contributions with interest.

Agreed on all counts - well said.

 

[sharpener]

WH356 protects the 50 mph crpossovers from up slow to up fast and there is no idication that there is anything untoward in the reaction to WH356 other than possible assumptions about the next signal.

In this post @baz962 says it normally would have gone through YY and G before 1H46 got there. However the report says "The signal protecting the junction was ... displaying a yellow aspect as the train passed it."

If normally going up fast from WH356 and the Up fast is clear , then it goes Y and as you get close to it it flashes through YY to green .t1H46

 

[ainsworth74]

We also don't know if the brakes were on or off on that unit, I would guess off, because if they had been fully applied is it not more likely the 360 would have climbed over the rear cab of the 810, and for there to have been even more damage to both?

Modern train vehicles are designed (and I include a 360 in that) to specifically avoid climbing over each other both within the formation and when they crash into another train. So I would say the expectation is that even in a violent collision two trains should lock together and not override the other.

 

[edwin_m]

The 810 was apparently standing at (the report says "next to") WH152. 5 car train of 24m car length: 120m. Add nominal standback distance of 25m, so rear of that train approximately 145m in rear of WH152.
It looks like it's been pushed maybe 3.5 coach lengths past the signal. 3.5 x 24, plus the standback of 25m = 109m.

It could actually be "next to" rather than "at". If the AWS applied the brake on the 810 while approaching a green signal at line speed, with four-aspect signals spaced at half the braking distance, it's quite possible that the front passed the next signal before it came to a stop. As far as I know we have no clear information on the position of the 810 immediately before the impact, but analysing the OTMR will provide that by working out the distance from features such as AWS magnets.

 

[Signal Head]

Without wanting to drag the thread off topic - and please feel free to move this to the TPWS thread if it is felt to be better warranted there, I've posted it here because of the other topics in my post - what astonishes me most, as a layman passenger who had previously assumed that all signals had TPWS, is the indication that the well-known risk of a SPAD after departing a station on a single yellow aspect, plus the well-known risk of a SPAD after accelerating from a speed restriction between the yellow and the red, plus the well-known risk of a driver being on autopilot when following a route where a single yellow is followed by a green 99% of the time, didn't combine to suggest that WH154 might need TPWS.

To be clear, WH356 was only showing Yellow because WH154 was Red. It isn't restricted to Yellow for the turnout move and when released by the berth track occupied will clear up to the least restrictive aspect depending upon what WH154 is displaying.

There is still the potential for a kind of anticipation though if, having seen a train go through on the UF, caution aspects are expected at the junction signal, but their meaning is overtaken by the expectation that that train will have got far enough ahead by the time of reaching the next signal.

I so not speculate that is what has happened in this case, but something must account for accelerating up to 76mph after a Yellow, and I'm sure that will be a key part of the investigation.

 

[Haywain]

In this post @baz962 says it normally would have gone through YY and G before 1H46 got there.

Normally is a dangerous precedent, particularly when normal doesn't happen.

 

[bramling]

Modern train vehicles are designed (and I include a 360 in that) to specifically avoid climbing over each other both within the formation and when they crash into another train. So I would say the expectation is that even in a violent collision two trains should lock together and not override the other.

This seems to have ended up working very well indeed. For a near 50mph impact the structure of the trains appears to have held up incredibly well. If it wasn’t for what seemed a disproportionate number of serious injuries I’d have estimated this as much closer to a 20-30 mph impact from images of the damage. Unfortunately this does seem to have resulted in a considerable number of secondary impacts.

There’s some postings on Facebook expressing concern about the level of damage to the 360 cab, but if the impact was at virtually 50 mph the fact that the cab is even recognisable means it’s held up pretty well considering, albeit sadly not well enough to have saved the driver.

 

[Signal Head]

It could actually be "next to" rather than "at". If the AWS applied the brake on the 810 while approaching a green signal at line speed, with four-aspect signals spaced at half the braking distance, it's quite possible that the front passed the next signal before it came to a stop. As far as I know we have no clear information on the position of the 810 immediately before the impact, but analysing the OTMR will provide that by working out the distance from features such as AWS magnets.

It has been the case in the past that the actual point of impact can be determined from specific track damage.

 

[Haywain]

I so not speculate that is what has happened in this case, but something must account for accelerating up to 76mph after a Yellow, and I'm sure that will be a key part of the investigation.

I can see why, having been given the road to go across to the up fast, the driver might accelerate and think a normal clear road is ahead but that does not explain passing a red signal and not braking until the train ahead is seen.

 

[baz962]

In this post @baz962 says it normally would have gone through YY and G before 1H46 got there. However the report says "The signal protecting the junction was ... displaying a yellow aspect as the train passed it."

Normally is a dangerous precedent, particularly when normal doesn't happen.

I did say when the upfast is clear. And to be clear I don't ever expect signals to clear and my post was in response to someone.

 

[devon_belle]

Actually to be honest with you, I personally feel that nine seconds for a drop from 76mph to 49mph actually seems impressive

I agree, and I think I would notice that deceleration. I've been on a couple of trains that have emergency stopped and you know the train is braking.

It comes to mind that at least one (possibly several) passenger interviews said that the train didn't noticeably brake before the collision. Maybe this person was thinking in terms of road vehicle deceleration, or simply didn't remember correctly due to the shock of the crash.

 

[GC class B1]

It equates to 3mph per second which is slightly above the 12%g figure required for emergency braking on mainline trains.

Agree. A speed reduction of 3 MPH per second is about 13.5%g.

 

[Signal Head]

In this post @baz962 says it normally would have gone through YY and G before 1H46 got there. However the report says "The signal protecting the junction was ... displaying a yellow aspect as the train passed it."

That suggests a 'two stage' approach release, which I am aware has been done in the past but is generally out of favour now. I wouldn't have expected it to have survived as a principle long enough to have been applied on the West Hampstead scheme, but it's possible I suppose.

In the example I'm thinking of, which I think has been altered by resignalling a few years ago, the signal (3 aspect) released from R to Y, and was held at that aspect irrespective of the aspect ahead of it, until the train had passed the AWS magnet, thereby always giving an AWS caution for the diverging move.

 

[D1511]

All the talk of signalling systems and AWS is fascinating to a signal layperson like myself, so thanks everyone for that.
But as a non train driver, what I'm struggling with is trying to imagine a set of circumstances where a speed of 76mph when the aspect of the previous 4 aspect signal was single amber is explicable. Can anyone help me with that? Can it only be as a result of presumption?

 

[thejuggler]

I can see why, having been given the road to go across to the up fast, the driver might accelerate and think a normal clear road is ahead but that does not explain passing a red signal and not braking until the train ahead is seen.

A medical issue before the incident is a valid explanation which will be investigated.

 

[CalderRail]

I did say when the upfast is clear. And to be clear I don't ever expect signals to clear and my post was in response to someone.

But it does raise the possibility that the 810 being there (not because of the AWS fault, but being there at all - it was running 18 late) may be a factor, and will be something RAIB look into.

 

[sharpener]

I did say when the upfast is clear. And to be clear I don't ever expect signals to clear and my post was in response to someone.

Yes, I thought yr post elsewhere was useful as an answer to a question implied by @Haywain here.

IMO a pity the thread was split as now the discussion has re-converged.

That suggests a 'two stage' approach release, which I am aware has been done in the past but is generally out of favour now.

Why is it out of favour, it would seem quite sensible to me as a means of distinguishing between (i) Y then G for negotiating the crossover expecting a clear road, and (ii) Y only for negotiating the crossover with a restrictive aspect beyond it?

Whether this was the design intent and whether it is/was expressly incorporated in driver training remains to be seen.

The _logical_ explanation of signalling systems as they have evolved seems to be fairly good, but the _psychology_ of the Human-Machine Interface seems to leave a lot to be desired. Cf the incident where IIRC there was a mainline green visible to the driver approaching the turnout.

ETA not Spital Junction, can't find the reference now.

 

[Crossover]

Absolutely. But we both know it won't stop the usual "case closed" attitude from many on here and the press when they read that initial briefing.

The lunatics are having a great time on Facebook. Apparently the driver is being made a scapegoat...even when more than one person pointed out that RAIB have only published a finding that the 360 passed a red signal and didn't give a reason because they don't know yet, the rants continued! A mention that the driver isn't being blamed because RAIB don't apportion blame produces much frothing at the mouth. The power of social media.

Oh yes, Facebook is an absolute cesspit of comments again tonight!

 

[Scotty Dog]

Sorry if already mentioned but in a dash and no time to read back

I wonder if the RAIB will look at the lack of yellow ends as a contributing factor to sighting the 810. I know it was a rear vehicle and many others trains have nothing yellow at rear but you can't get away from the lack of sighting.

 

[CalderRail]

Oh yes, Facebook is an absolute cesspit of comments again tonight!

When is it not? It's a platform for the ignorant to yell nonsense at the uninformed and the disinterested.

 

[Ferret]

Sorry if already mentioned but in a dash and no time to read back

I wonder if the RAIB will look at the lack of yellow ends as a contributing factor to sighting the 810. I know it was a rear vehicle and many others trains have nothing yellow at rear but you can't get away from the lack of sighting.

The 810 was at a stand around a bend. Not sure how much yellow ends would’ve helped? Maybe on a straight section, it could be an issue, but a lot has potentially gone wrong to get to the point of collision already.

 

[AlterEgo]

Sorry if already mentioned but in a dash and no time to read back

I wonder if the RAIB will look at the lack of yellow ends as a contributing factor to sighting the 810. I know it was a rear vehicle and many others trains have nothing yellow at rear but you can't get away from the lack of sighting.

The 810 was on a curve and it seems most likely that it was concealed from the 360's driver until maybe 10-15 seconds before impact.

 

[Bigfoot]

Modern train vehicles are designed (and I include a 360 in that) to specifically avoid climbing over each other both within the formation and when they crash into another train. So I would say the expectation is that even in a violent collision two trains should lock together and not override the other.

This seems to have ended up working very well indeed. For a near 50mph impact the structure of the trains appears to have held up incredibly well. If it wasn’t for what seemed a disproportionate number of serious injuries I’d have estimated this as much closer to a 20-30 mph impact from images of the damage. Unfortunately this does seem to have resulted in a considerable number of secondary impacts.

There’s some postings on Facebook expressing concern about the level of damage to the 360 cab, but if the impact was at virtually 50 mph the fact that the cab is even recognisable means it’s held up pretty well considering, albeit sadly not well enough to have saved the driver.

It is also from memory the first major crash involving two modern units at any great speed. The analysis of how they performed will also be an interesting part of the investigation.

 

[Haywain]

But as a non train driver, what I'm struggling with is trying to imagine a set of circumstances where a speed of 76mph when the aspect of the previous 4 aspect signal was single amber is explicable. Can anyone help me with that? Can it only be as a result of presumption?

I suspect that we are going to have to wait a while to get the answer to that. All we know is that the speed of 76 mph was what had been achieved immediately prior to the braking, and not whether that was full acceleration from WH356 or after traversing the crossover.

 

[gravitystorm]

what I'm struggling with is trying to imagine a set of circumstances where a speed of 76mph when the aspect of the previous 4 aspect signal was single amber is explicable. Can anyone help me with that?

That's not the sequence of events. The sequence given by the RAIB is:

• Platform signal at Yellow
• Junction signal at Yellow
• Up Slow to Up Fast
• WH154 (red)
• 76mph 9 seconds before collision
• collision just before reaching WH152

The given speed was at a position well after passing the WH154 signal at red. There's no information released so far as to what speed the train was doing over the junction, between the junction and WH154, and what the speed (or acceleration) looked like after WH154 was passed.

 

[Annetts key]

Without wanting to drag the thread off topic - and please feel free to move this to the TPWS thread if it is felt to be better warranted there, I've posted it here because of the other topics in my post - what astonishes me most, as a layman passenger who had previously assumed that all signals had TPWS, is the indication that the well-known risk of a SPAD after departing a station on a single yellow aspect, plus the well-known risk of a SPAD after accelerating from a speed restriction between the yellow and the red, plus the well-known risk of a driver being on autopilot when following a route where a single yellow is followed by a green 99% of the time, didn't combine to suggest that WH154 might need TPWS. We've been waiting for ATP, then ETCS, for the best part of 30 years; when might it be time to admit that we're simply waiting for Godot, and that saving the cost of making the railway more safe now, to pay for an indeterminate signalling system in the indeterminate future, might not be the best idea? In that respect, this accident is more redolent of accidents from the early days of AWS, a lifetime or more ago, or, indeed, Ladbroke Grove. And it may be that, like Ladbroke Grove, or, going back further, Grantham (1906), the reason for the train continuing may never be explained. But to pass this off as a freak accident would doom us into repeating it, and the unfortunate driver's death is one too many.

Well, ultimately, most of the past decisions on ATP, TPWS and ETCS/ERTMS come down to cost, and hence it's a political decision.

Neither of the two ATP pilot schemes became a nationwide standard.

TPWS was supposed to be a "low cost" system to deal with what was considered to be the highest risks, but was never intended to be fitted to all main aspect signals (or all main semaphore signals).

And the roll out of ETCS/ERTMS has taken a lot longer than many in the industry expected. Part of the reason for this is a limited budget. Although there are other reasons.

If you are interested in the subject of train protection systems, I do recommend reading the Investigation into the Clapham Junction Railway Accident by Anthony Hidden QC, available here.

And reading the Joint Inquiry into Train Protection Systems (often called the Uff-Cullen Inquiry) by Professor John Uff QC FREng and The Rt Hon Lord Cullen PC available here.

See also this web page.

 

[dk1]

Oh yes, Facebook is an absolute cesspit of comments again tonight!

I find it best to just not read the comments especially on the tabloid newspaper sites. It has too much effect on the blood pressure.

 

[Signal Head]

Yes, I thought yr post elsewhere was useful as an answer to a question implied by @Haywain here.

IMO a pity the thread was split as now the discussion has re-converged.



Why is it out of favour, it would seem quite sensible to me as a means of distinguishing between (i) Y then G for negotiating the crossover expecting a clear road, and (ii) Y only for negotiating the crossover with a restrictive aspect beyond it?

Whether this was the design intent and whether it is/was expressly incorporated in driver training remains to be seen.

The _logical_ explanation of signalling systems as they have evolved seems to be fairly good, but the _psychology_ of the Human-Machine Interface seems to leave a lot to be desired. Cf the incident where IIRC there was a mainline green visible to the driver approaching the turnout.

ETA not Spital Junction, can't find the reference now.

I cannot recall the document, or date, when it was, I think, effectively banned. I did manage to implement something similar a few years ago for very specific sighting reasons, but it was permitted only on the basis that the aspect would be unrestricted before the train reached the AWS, so the AWS did not 'lie' to the driver.

I've managed to check some old drawings for the Bedford area, and they confirm that 356 does (or at least did originally, it may have been changed since of course) have a two stage aspect release. Release from R to Y took place some distance from the signal, 'better aspects' require the immediate berth TC occupied, which happens after passing the AWS.

So, under these conditions, drivers will be used to getting Y + Pos 4 initially, then the aspect may (and probably most often will) step up as they get nearer but they will be cancelling the AWS warning every time, irrespective of what aspect they end up with.

I will be very surprised if that goes uncommented upon in the final report, assuming it still works that way.

 

[mrshed]

The 810 was on a curve and it seems most likely that it was concealed from the 360's driver until maybe 10-15 seconds before impact.

Under discussed but mentioned above is where 5Z14 was during all this, coming the other way.

The timings put it quite possibly alongside the 810 at around the time the 810 would have become visible, and there's a possibility it could have contributed to visibility.