HSTs - Are they sufficently crashworthy now, should they be withdrawn?

[najaB]

*rolls eyes*

You can roll your eyes, but @Bletchleyite is right. There's only a fixed pot of money so it should be spent where it gives maximum benefit. Where transportation safety is concerned the priority should be on road interventions because roads are much more dangerous than railways. In 11 of the last 12 years there have been 10 or fewer passenger fatalities on the mainline railway. As compared to over 1,7000 road fatalities in each of those years.

The money that would be spent replacing the HSTs five years early would be much better spent fixing deficiencies in the road network.

There's a case for replacing the HSTs because they're more expensive to operate, because they put out a lot more CO2, because they aren't as reliable or aren't as accessible as a new fleet would be, but there's no case to be made on the grounds of safety. At least not until the RAIB or similar reports that they are objectively unsafe.

 

[GlitterUnicorn]

You can roll your eyes, but @Bletchleyite is right. There's only a fixed pot of money so it should be spent where it gives maximum benefit. Where transportation safety is concerned the priority should be on road interventions because roads are much more dangerous than railways. In 11 of the last 12 years there have been 10 or fewer passenger fatalities on the mainline railway. As compared to over 1,7000 road fatalities in each of those years.

The money that would be spent replacing the HSTs five years early would be much better spent fixing deficiencies in the road network.

There's a case for replacing the HSTs because they're more expensive to operate, because they put out a lot more CO2, because they aren't as reliable or aren't as accessible as a new fleet would be, but there's no case to be made on the grounds of safety. At least not until the RAIB or similar reports that they are objectively unsafe.

Rail safety is not road safety, they're incomparable. We aspire to having the safest railway in the world because we believe that there is no acceptable level of fatalities or injuries. We don't aspire to mediocrity or the "that'll do" attitude or comfort ourselves in statistics that it's safer than driving a car.

Had this train been fully loaded it could have been the worst accident on Britain's railways in terms of fatalities in 50 years, if not more. It was sheer blind luck that the train only had nine people onboard, three of whom lost their lives. Had this happened we'd have seen far more of an outcry than one driver speaking up about it.

This isn't a case of these trains suddenly becoming unsafe. This is about the decision of Scotrail, Transport Scotland and/or the Scottish Government deciding that 40+ year old trains were a suitable choice to serve on these routes for at least the next decade. When there was an option to introduce trains that conform to modern safety standards. It's a speculative thread, and I think the fact that one of Scotland's newly introduced high speed trains came out of this crash so badly leaves room for speculation that there's maybe something wrong with the train, or that Transport Scotland ought not to have opted to refurbish 40+ year old trains and instead should have footed the bill for something built in this bloody century.

 

[HSTEd]

leaves room for speculation that there's maybe something wrong with the train, or that Transport Scotland ought not to have opted to refurbish 40+ year old trains and instead should have footed the bill for something built in this bloody century.

Or this was the sort of high energy impact that was going to cause serious problems no matter how modern the train was?

At some point, even modern crash safety standards must give way to physics.

 

[Killingworth]

Rail safety is not road safety, they're incomparable. We aspire to having the safest railway in the world because we believe that there is no acceptable level of fatalities or injuries. We don't aspire to mediocrity or the "that'll do" attitude or comfort ourselves in statistics that it's safer than driving a car.

Had this train been fully loaded it could have been the worst accident on Britain's railways in terms of fatalities in 50 years, if not more. It was sheer blind luck that the train only had nine people onboard, three of whom lost their lives. Had this happened we'd have seen far more of an outcry than one driver speaking up about it.

This isn't a case of these trains suddenly becoming unsafe. This is about the decision of Scotrail, Transport Scotland and/or the Scottish Government deciding that 40+ year old trains were a suitable choice to serve on these routes for at least the next decade. When there was an option to introduce trains that conform to modern safety standards. It's a speculative thread, and I think the fact that one of Scotland's newly introduced high speed trains came out of this crash so badly leaves room for speculation that there's maybe something wrong with the train, or that Transport Scotland ought not to have opted to refurbish 40+ year old trains and instead should have footed the bill for something built in this bloody century.

There have been a lot of railway accidents that resulted in no fatalities, and no doubt many near misses.

Just one of them could have resulted in a disaster to rival Qunitinshill if a combination of bad circumstances all lined up together. Fortunately they didn't.

We can go 5, 10 or 20 years without a major loss of life, but eventually a bad combination will occur. An HST might be involved but more likely a more modern train - odds based on numbers.

It's the belching HST black smoke I don't like.

 

[Ianno87]

Rail safety is not road safety, they're incomparable. We aspire to having the safest railway in the world because we believe that there is no acceptable level of fatalities or injuries. We don't aspire to mediocrity or the "that'll do" attitude or comfort ourselves in statistics that it's safer than driving a car.

The UK rail network strives to minimise and manage safety risk to a level that is "as low as reasonably practicable". With a target that everybody goes home safe, every day.

 

[yorksrob]

Rail safety is not road safety, they're incomparable. We aspire to having the safest railway in the world because we believe that there is no acceptable level of fatalities or injuries. We don't aspire to mediocrity or the "that'll do" attitude or comfort ourselves in statistics that it's safer than driving a car.

I think that's a ridiculous way to look at risk, personally.

Fundamentally, it's that inability to look at risk proportionately, that makes it so often prohibitively expensive to improve the railway service.

 

[edwin_m]

The simple TPWS interfaces both onboard the trains and with the trackside signalling not only reduced the cost significantly compared to any available full supervision ATP system of the time, but also allowed network-wide fitment at the highest risk junction locations in an extraordinarily short timescale, hence delivering the safety improvement much more quickly. ATP could easily have taken 3 or 4 times as long to roll out.

And would now have been obsolete, only 20 years later, because everyone is moving to ETCS. The sorts of transitional issues we've seen with the Heathrow Crossrail service would have been replicated in many other places, taking a lot of money and talent to resolve that could have been employed in actually making the railway better.

Rail safety is not road safety, they're incomparable. We aspire to having the safest railway in the world because we believe that there is no acceptable level of fatalities or injuries. We don't aspire to mediocrity or the "that'll do" attitude or comfort ourselves in statistics that it's safer than driving a car.

I don't know exactly who you are including in "we", but the rail industry works on the ALARP principle that is at the heart of UK health and safety law. That means "as low as reasonably practicable". A safety measure that is too expensive or has other downsides can be deemed not reasonably practicable and not introduced. Behind this, there is in fact an acceptable level of fatalities or injuries - expressed as "value of preventing a fatality" or similar.

Road and rail safety are directly comparable. Most people planning a train journey have an alternative of driving, where the chances of being killed are typically at least five times as great. If you're looking for perfect safety then you need to stay in bed and hope you're not hit by a meteorite.

 

[Ianno87]

. Behind this, there is in fact an acceptable level of fatalities or injuries - expressed as "value of preventing a fatality" or similar.

Not quite - that nominal "value" is used for calculating the business case for a safety intervention, to assess whether the cost of an intervention is likely to be "worth it" with respect to the resulting safety gain (noting that any money "saved" as a result could be more effectively spent on something else).

ATP/TPWS is a good example. TPWS won the day, because you get the biggest chunk of benefits that ATP would have, but for a fraction of the price.

Sinplistically:
TPWS = As Low As Reasonably Practicable
ATP = "Safety at all costs" (I.e.the marginal improvment abve TPWS comes at disproportionate expense relative to the benefit).

 

[edwin_m]

Not quite - that nominal "value" is used for calculating the business case for a safety intervention, to assess whether the cost of an intervention is likely to be "worth it" with respect to the resulting safety gain (noting that any money "saved" as a result could be more effectively spent on something else).

ATP/TPWS is a good example. TPWS won the day, because you get the biggest chunk of benefits that ATP would have, but for a fraction of the price.

Sinplistically:
TPWS = As Low As Reasonably Practicable
ATP = "Safety at all costs" (I.e.the marginal improvment abve TPWS comes at disproportionate expense relative to the benefit).

That's a different way of putting it - if there is no business case for the intervention then the safety risk of not making the intervention is tolerable and indeed tolerated.

I was involved in the project that identified the concept of TPWS back in 1994ish. We analysed accident reports back to about 1968 to assess whether the outcome would have been different had a TPWS-like system been operational at the time, and made an allowance for other safety improvements in the meantime such as better rolling stock crashworthiness. The result was that TPWS would capture something like 80% (from memory) of the safety benefits of ATP - a figure that was looked at with some disdain by Uff and Cullen but has since been largely borne out by events.

 

[Wolfie]

Edit: Posts #1 - #25 originally in this thread.

Interesting piece on HST safety in the news today.

Rail engineer calls for ScotRail fleet involved in Stonehaven crash to be scrapped

A rail engineer has called for the type of train involved in the tragic Stonehaven derailment to be scrapped amid safety concerns. Gareth Dennis has said

www.google.com

Pretty damning stuff, really.

Extending his logic to the obvious ultimate conclusion you would have to withdraw all existing trains every time that safety standards change, which would be utter nonsense. Why only trains too? Airliners, coaches, buses, cars....

Obviously if older items are evaluated as excessively risky (eg Mk 1 and earlier stock, slam doors etc) that is a different issue.

 

[Bletchleyite]

Extending his logic to the obvious ultimate conclusion you would have to withdraw all existing trains every time that safety standards change, which would be utter nonsense. Why only trains too? Airliners, cars....

And rewire every house every time a new Edition of the Regulations is released?

 

[Wolfie]

It is only "damning stuff" until you realise that Gareth Dennis is a commentator who's professional competency is apparently civil engineering, so not a traction and rolling stock engineer. Add on his political angle and his desire for self-promotion and you can see where a sensationalist headline comes from. I'd rather wait and see what the RAIB come up with - who do have professional rolling stock experts on the payroll - rather than listening to some media gobs**** spouting off.

The reality is, no they are not as safe as a 21st century design, but it doesn't make them unsafe.

Balanced.

 

[43096]

I was involved in the project that identified the concept of TPWS back in 1994ish. We analysed accident reports back to about 1968 to assess whether the outcome would have been different had a TPWS-like system been operational at the time, and made an allowance for other safety improvements in the meantime such as better rolling stock crashworthiness. The result was that TPWS would capture something like 80% (from memory) of the safety benefits of ATP - a figure that was looked at with some disdain by Uff and Cullen but has since been largely borne out by events.

A question I have asked before.... what was the last fatal accident that could only have been prevented by ATP i.e. AWS/TPWS would have been ineffective?

 

[edwin_m]

A question I have asked before.... what was the last fatal accident that could only have been prevented by ATP i.e. AWS/TPWS would have been ineffective?

That would have been somewhere in the depths of the analysis I mentioned, but if I ever knew I can't recall. I doubt there were any since 1994 when the analysis was done.

 

[AlterEgo]

I'm not asking for it to be closed, I'm asking for you to have some respect.

The driver ought to have shown some respect for the deceased and his or her colleagues by refraining to spout one-sided nonsense until the investigation has been completed.

Rail safety is not road safety, they're incomparable. We aspire to having the safest railway in the world because we believe that there is no acceptable level of fatalities or injuries.

You’re right that they’re incomparable. You’re not looking at the holistic picture though - if we belt and braces everything on the railway x100, it either becomes prohibitively expensive for the average punter or you end up doing things like vastly reducing the size of your fleet and timetable. This means more people go onto the roads, which are demonstrably far, far less safe and more likely to kill you.

Had this train been fully loaded it could have been the worst accident on Britain's railways in terms of fatalities in 50 years, if not more. It was sheer blind luck that the train only had nine people onboard, three of whom lost their lives. Had this happened we'd have seen far more of an outcry than one driver speaking up about it.

It would be great if the outcry here, led by a self-promoting railway civil engineer with no specialism whatsoever in the design of trains or vehicles, was about the severe failure of...guess what...the railway civil engineering at the site.

This outcry is like complaining about your last line of defence. No point complaining your goalkeeper failed to save a shot when you have ten other players whose job it is to prevent goals who were all standing still when it happened!

 

[Ianno87]

A question I have asked before.... what was the last fatal accident that could only have been prevented by ATP i.e. AWS/TPWS would have been ineffective?

A bit of speculation on my part, but at Ladbroke Grove it would have in theory stopped the Turbo within the signal overlap after it Spadded SN109.

At Southall (much higher speed approach), TPWS would have at least reduced the severity of the accident by intervening on the speed sooner than the driver did (I think - happy to be shot down by an actual TPWS expert on this)

 

[edwin_m]

A bit of speculation on my part, but at Ladbroke Grove it would have in theory stopped the Turbo within the signal overlap after it Spadded SN109.

At Southall (much higher speed approach), TPWS would have at least reduced the severity of the accident by intervening on the speed sooner than the driver did (I think - happy to be shot down by an actual TPWS expert on this)

At Ladbroke Grove the distance from SN109 to the convergence of the tracks was enough for a TPWS brake application to stop the train safely if both had been TPWS-fitted, as they would have been under the later programme.

Southall would have been prevented by a working AWS (very likely) or a working ATP (certainly) or a working TPWS (almost certainly if fitted). I suppose you can argue that if TPWS had been fitted it might not have been working either, given the attitude to train protection systems at the time. But it would be a stretch to say that Southall was ATP-preventable without also agreeing that it would have been prevented by AWS or TPWS under the same assumptions.

 

[Ianno87]

At Ladbroke Grove the distance from SN109 to the convergence of the tracks was enough for a TPWS brake application to stop the train safely if both had been TPWS-fitted, as they would have been under the later programme.

Southall would have been prevented by a working AWS (very likely) or a working ATP (certainly) or a working TPWS (almost certainly if fitted). I suppose you can argue that if TPWS had been fitted it might not have been working either, given the attitude to train protection systems at the time. But it would be a stretch to say that Southall was ATP-preventable without also agreeing that it would have been prevented by AWS or TPWS under the same assumptions.

The closest "near-miss" I believe we've had (in terms of a SPAD that could have been a very serious accident has circumstances been slightly different) was the Wootton Basset SPAD - which only happened as severely as it did because the AWS (and as a consequence TPWS) had been isolated.

 

[edwin_m]

The closest "near-miss" I believe we've had (in terms of a SPAD that could have been a very serious accident has circumstances been slightly different) was the Wootton Basset SPAD - which only happened as severely as it did because the AWS (and as a consequence TPWS) had been isolated.

Indeed so. But a bit like Southall, in the unlikely event of a steam loco being fitted with ATP, that would probably have been isolated as well.

 

[ainsworth74]

The forces in the Carmont crash were overwhelming and catastrophic. Any train would be seriously damaged in that situation and there would be little chance of survival for the driver.

Is that necessarily true? Was not Grayrigg equally overwhelming and catastrophic in the forces that were exerted? Grayrigg had a nine vehicle 390 which derailed on a gentle curve going at 95mph, smashed its way through I believe six OHLE masts and bases (leading vehicle went through two, the second through four), fell down a 15m (ish) embankment, vehicles jack-knifed and rolled over on their way down the embankment. Carmont had a six vehicle HST which derailed on a gentle curve going at 73mph, the leading power car smashed its way through the bridge parapet before falling down the 12m (ish) embankment/from the bridge, vehicles jack-knifed and rolled over (only one passenger vehicle fell down the embankment) before ending up in a tangled mess together.

Different accidents to be sure. But I'm not sure it's possible to characterise Carmont as being a fundamentally more catastrophic accident and therefore the damage as being understandable when we have Grayrigg which is very similar (arguably even worse with a higher speed, a larger embankment, multiple vehicles taking hits from OHLE masts, a heavier train with more energy to dissipate) and had a less bad outcome (but still recalling that sadly one passenger lost their life at Grayrigg so I wouldn't it was by any stretch 'good').

I don't know the answers, I suspect that the RAIB report will make for interesting reading in the performance of that train at that accident site. But it strikes me that we might be falling into a trap of considering that Carmont was so extreme as to consider that it would not be possible for a train to offer significant protection to its passengers and crew. When I'm not so sure that is the case when there's an accident like Grayrigg to look at.

 

[43096]

At Southall (much higher speed approach), TPWS would have at least reduced the severity of the accident by intervening on the speed sooner than the driver did (I think - happy to be shot down by an actual TPWS expert on this)

As a result of the AWS isolation, Southall was a pre-1910 accident in 1997. Essentially it was AWS preventable.

 

[bramling]

Is that necessarily true? Was not Grayrigg equally overwhelming and catastrophic in the forces that were exerted? Grayrigg had a nine vehicle 390 which derailed on a gentle curve going at 95mph, smashed its way through I believe six OHLE masts and bases (leading vehicle went through two, the second through four), fell down a 15m (ish) embankment, vehicles jack-knifed and rolled over on their way down the embankment. Carmont had a six vehicle HST which derailed on a gentle curve going at 73mph, the leading power car smashed its way through the bridge parapet before falling down the 12m (ish) embankment/from the bridge, vehicles jack-knifed and rolled over (only one passenger vehicle fell down the embankment) before ending up in a tangled mess together.

Different accidents to be sure. But I'm not sure it's possible to characterise Carmont as being a fundamentally more catastrophic accident and therefore the damage as being understandable when we have Grayrigg which is very similar (arguably even worse with a higher speed, a larger embankment, multiple vehicles taking hits from OHLE masts, a heavier train with more energy to dissipate) and had a less bad outcome (but still recalling that sadly one passenger lost their life at Grayrigg so I wouldn't it was by any stretch 'good').

I don't know the answers, I suspect that the RAIB report will make for interesting reading in the performance of that train at that accident site. But it strikes me that we might be falling into a trap of considering that Carmont was so extreme as to consider that it would not be possible for a train to offer significant protection to its passengers and crew. When I'm not so sure that is the case when there's an accident like Grayrigg to look at.

The only thing you can really take away is that both accidents are different. It only takes one tiny thing to drastically alter the outcome.

 

[najaB]

But it strikes me that we might be falling into a trap of considering that Carmont was so extreme as to consider that it would not be possible for a train to offer significant protection to its passengers and crew. When I'm not so sure that is the case when there's an accident like Grayrigg to look at.

They appear to be roughly similar in terms of energy involved but at Carmont the accident sequence was quite different. It's difficult to say how a 390 would have reacted given the same forces. There almost certainly would have been less damage, but it's very hard to say how much less.

 

[Bletchleyite]

They appear to be roughly similar in terms of energy involved but at Carmont the accident sequence was quite different. It's difficult to say how a 390 would have reacted given the same forces. There almost certainly would have been less damage, but it's very hard to say how much less.

Add to that that a 390 is a 155mph unit, and probably the most crashworthy of those too. I reckon if you compare the HST with something that is more equivalent in terms of what might have ended up used instead, such as a 170 or even a 195, or a 68 and Mk5s*, the HST wouldn't look so bad.

A 390 is also an EMU and so isn't going to catch fire, whereas the crash did involve fire, which if I recall destroyed one of the vehicles. I wonder how a Voyager would have performed?

* Though with those being 22m vehicles, the overhang is quite small so they may have jack-knifed less.

 

[ainsworth74]

They appear to be roughly similar in terms of energy involved but at Carmont the accident sequence was quite different. It's difficult to say how a 390 would have reacted given the same forces. There almost certainly would have been less damage, but it's very hard to say how much less.

Absolutely. For one thing the HST came to a stand in a much shorter distance than the 390 did, even accounting for the lower speed that must mean far more energy was being dissipated into the vehicles rather than than dragging through ballast, etc. My main concern is that there seems to be a growing opinion on this thread that Carmont was an extreme outlier of what could happen to a derailed train when to my mind there is at least one very similar (though yes different!) accident out there.

 

[Domh245]

Is that necessarily true? Was not Grayrigg equally overwhelming and catastrophic in the forces that were exerted? Grayrigg had a nine vehicle 390 which derailed on a gentle curve going at 95mph, smashed its way through I believe six OHLE masts and bases (leading vehicle went through two, the second through four), fell down a 15m (ish) embankment, vehicles jack-knifed and rolled over on their way down the embankment. Carmont had a six vehicle HST which derailed on a gentle curve going at 73mph, the leading power car smashed its way through the bridge parapet before falling down the 12m (ish) embankment/from the bridge, vehicles jack-knifed and rolled over (only one passenger vehicle fell down the embankment) before ending up in a tangled mess together.

Whilst Grayrigg would have had more energy (around 3x as much), the RAIB report says it stopped within about 320m of the derailment point whilst at Stonehaven it hit the bridge parapet 60m after derailing. The longer stopping distance at Grayrigg would have resulted in (on average) lower forces as a result of the lower average deceleration

Absolutely. For one thing the HST came to a stand in a much shorter distance than the 390 did, even accounting for the lower speed that must mean far more energy was being dissipated into the vehicles rather than than dragging through ballast, etc. My main concern is that there seems to be a growing opinion on this thread that Carmont was an extreme outlier of what could happen to a derailed train when to my mind there is at least one very similar (though yes different!) accident out there.

Using the numbers above, I make the average force at Stonehaven a little over twice the force at Greyrigg, though there's a lot more to it than basic mechanics, particularly as individual vehicles would have each experienced rather different forces throughout the incidents.

The similarity between incidents is purely a coincidence of where they both happened than anything else

 

[HSTEd]

The Ultimate example of how there are limits on what crashworthiness can achieve is probably Eschede.

Slamming into a pile of concrete at those speeds, everyone simply dies.

 

[Bletchleyite]

The Ultimate example of how there are limits on what crashworthiness can achieve is probably Eschede.

Slamming into a pile of concrete at those speeds, everyone simply dies.

I was actually going to mention Eschede, though that was even more extreme than the Scottish example.

 

[XAM2175]

My main concern is that there seems to be a growing opinion on this thread that Carmont was an extreme outlier of what could happen to a derailed train when to my mind there is at least one very similar (though yes different!) accident out there.

I also note some similarities with the high-speed derailment of an XPT set in Victoria in February last year:

Investigation: RO-2020-002 - Derailment of XPT ST23, Wallan, Victoria, on 20 February 2020

At about 1943, XPT ST23 was approaching the northern end of Wallan Loop at about the track’s line speed [130 km/h, 81 mi/h]. Recordings from the train indicate an Emergency brake application a short distance before the points. This slowed the train a small amount before it entered the turnout travelling at a speed in excess of 100 km/h. The train was not able to negotiate the turnout to the loop track at this speed and derailed. All vehicles derailed excepting the rear power car. ...

During the derailment sequence, the leading power car rolled onto its left side and the XPT driver and the [Accompanying Qualified Worker] sustained fatal injuries. Three passengers were seriously injured and 36 received minor injuries. Five train crew that were in the passenger cars also sustained injuries.

Noting that XPT power cars are licensed derivatives of the HST design and thus are (to the best of my knowledge) reasonably similar in construction, while XPT trailers are built to the manufacturer's own design but are still broadly comparable as contemporaries of the Mark 3 coach.

 

[HSTEd]

If anything, this possibly demonstrates that fitting magnetic track brakes to stock would be useful, because it would provide very large quantities of emergency brakeforce.

That would significantly reduce accident energies in these situations where an attempt to brake before the accident occurs.