Signal Passed at Danger (SPAD) and near miss at Sileby Junction 05/05/2021

[Efini92]

Some pretty shocking failures there; it's only through sheer luck that an actual collision was avoided.

Whilst having a SPAD on your record shouldn't automatically mean instant dismissal or disqualification from applying for a driver role, clearly this driver did not have the required skills, or perhaps qualities, to be operating trains safely. As proven by the fact they now have two RAIB reports to their name!

There's also a worrying accountability gap here because, as with many RAIB reports, we are again reminded that decade-old recommendations have still not been fully implemented. It's no good having the RAIB simply make recommendations if they don't have the power to force companies to comply.

It's frankly astonishing that the rail network doesn't have more incidents, with so many holes in the Swiss cheese just waiting to line up...

You’ve hit the nail on the head there.
Too many people think tpws is the magic bullet. There have been a few incidents in recent years where a major accident was only avoided by luck.

 

[Watershed]

You’ve hit the nail on the head there.
Too many people think tpws is the magic bullet. There have been a few incidents in recent years where a major accident was only avoided by luck.

Indeed and with ETCS still decades away on most lines, I'm not convinced that TPWS is a sufficient safeguard in the meantime. Certainly not for poorer braking traction - MPVs, OTMs, heavy freights, unbraked drags...

There also seem to have been a disproportionate number of SPADs in the Syston/Sileby area in recent years. The report briefly mentions that the Slow Line signals are located parallel with the Fast Line ones - which means that the Slow Lines are hugely overbraked, having around half the linespeed (65 vice 110/HST 115) yet still the same 2.5km spacing. This is a risk which doesn't seem to have been fully factored into the positioning and trigger speeds for the OSS loops. Really there ought to be TPWS+ loops with that sort of signal spacing.

 

[Efini92]

Indeed and with ETCS still decades away on most lines, I'm not convinced that TPWS is a sufficient safeguard in the meantime. Certainly not for poorer braking traction - MPVs, OTMs, heavy freights, unbraked drags...

There also seem to have been a disproportionate number of SPADs in the Syston/Sileby area in recent years. The report briefly mentions that the Slow Line signals are located parallel with the Fast Line ones - which means that the Slow Lines are hugely overbraked, having around half the linespeed (65 vice 110/HST 115) yet still the same 2.5km spacing. This is a risk which doesn't seem to have been fully factored into the positioning and trigger speeds for the OSS loops. Really there ought to be TPWS+ loops with that sort of signal spacing.

I also think double blocking all conflicting moves should be standard. As annoying as it is, I’d rather have the extra section as protection from a poorly braked train.

 

[Watershed]

I also think double blocking all conflicting moves should be standard. As annoying as it is, I’d rather have the extra section as protection from a poorly braked train.

With poorly braked trains, yes, that's probably a sensible mitigation until TPWS+ loops or some other solution can be applied.

 

[43066]

It's frankly astonishing that the rail network doesn't have more incidents, with so many holes in the Swiss cheese just waiting to line up...

Largely down to the skill and dedication of the drivers and signallers concerned (and all other safety critical roles of course). Inevitably it goes wrong (very) occasionally.

I'm not convinced that TPWS is a sufficient safeguard in the meantime. Certainly not for poorer braking traction - MPVs, OTMs, heavy freights, unbraked drags...

Not sure this is really borne out by the stats? There’s been, what, three (train accident related) fatalities on the network since Grayrigg in 2007? We really are at the point of diminishing returns when it comes to rail safety, TPWS will do until ETCS is rolled out (the drivers of this not being safety, of course).

 

[Efini92]

Largely down to the skill and dedication of the drivers and signallers concerned! Of course it goes wrong (very) occasionally.



Not sure this is really borne out by the stats? There’s been, what, three fatalities on the network since Grayrigg in 2007? We really are at the point of diminishing returns when it comes to rail safety, TPWS will do until ETCS is rolled out (the drivers of this not being safety, of course).

Look at the near misses.
There was Wooton Bassett, GBRF had two in quick succession a few years ago and the one at Syston. With the exception of the Edinburgh sleeper, I was only luck that avoided a serious collision.

 

[43066]

Look at the near misses.
There was Wooton Bassett, GBRF had two in quick succession a few years ago and the one at Syston. With the exception of the Edinburgh sleeper, I was only luck that avoided a serious collision.

Wootton Bassett was down to the criminal actions of the driver concerned undertaking an unauthorised isolation of the TPWS, so I wouldn’t count that as an “accident”. There are other near misses which the industry seems fairly good at learning from.

Don’t get me wrong, I’m not suggesting we should become complacent, but I don’t think there’s much scope for arguing for much greater safety measures than we already have when we are still (AFAIK) the safest railway in Europe.

 

[Efini92]

Wootton Bassett was down to the criminal actions of the driver concerned isolating the TPWS, so I wouldn’t count that as an “accident”. There are other near misses which the industry seems fairly good at learning from.

Don’t get me wrong, I’m not suggesting we should become complacent, but I don’t think there’s much scope for arguing for much greater safety measures than we already have when we are still (AFAIK) the safest railway in Europe.

If we’re being technical it was the fireman that isolated the aws
But you’re right that is in a different category. Though had the junction been double blocked they would’ve responded to the earlier danger signal and stopped in that section instead of on the junction.

I agree we are the safest, but it does seem complacency is creeping in. There’s been a rise in incidents that could’ve had serious consequences in the last few years.

 

[304033]

With poorly braked trains, yes, that's probably a sensible mitigation until TPWS+ loops or some other solution can be applied.

A 'solution' without TPWS+:
Approached control before final protecting signal.
Ie: GR, YY, Y, R (turns Y from approach control), R = Protected Junction. And if this already exists, why isnt put into practice at every junction where there is even the remotest possibility of a collision.

When looking at that diagram in the RAIB report earlier, I cant quite get over how lucky this was... Yes, it was ECS but even then that shouldnt be a reason for complacency. Just imagine if this was a passenger service and had been going a little slower...

 

[Efini92]

A 'solution' without TPWS+:
Approached control before final protecting signal.
Ie: GR, YY, Y, R (turns Y from approach control), R = Protected Junction. And if this already exists, why isnt put into practice at every junction where there is even the remotest possibility of a collision.

When looking at that diagram in the RAIB report earlier, I cant quite get over how lucky this was... Yes, it was ECS but even then that shouldnt be a reason for complacency. Just imagine if this was a passenger service and had been going a little slower...

That’s pretty much double blocking. It does exist in a lot of places.

 

[Watershed]

That’s pretty much double blocking. It does exist in a lot of places.

But, with a handful of exceptions, that only exists where there isn't enough space for a standard overlap. Hence approach controlled double red protection is applied to trains that approach the signal protecting the junction.

 

[Efini92]

But, with a handful of exceptions, that only exists where there isn't enough space for a standard overlap. Hence approach controlled double red protection is applied to trains that approach the signal protecting the junction.

Fair point

 

[Watershed]

A 'solution' without TPWS+:
Approached control before final protecting signal.
Ie: GR, YY, Y, R (turns Y from approach control), R = Protected Junction. And if this already exists, why isnt put into practice at every junction where there is even the remotest possibility of a collision.

It already exists in some areas and there's no fundamental technical reason why it couldn't be implemented everywhere (albeit modifying old mechanical or relay based interlockings would be "interesting").

The reason why it's not done everywhere is that it would significantly reduce capacity and would essentially break a lot of timetables. You'd have to completely rewrite them with higher junction margins and in many cases that would necessitate reducing frequencies.

As always, it's a question of cost vs benefit (or risk vs reward, if you prefer). Double red protection is probably justified in certain cases, such as trains with a lower braking rate than is assumed by the TPWS calculations. But not for every single train, considering that on most lines the vast majority of traffic consists of high-performing multiple units.

Alternatively I think it would be reasonable to limit poorly braked trains to a lower speed limit. I'm honestly quite surprised that a 4.6%g rated rail grinder was certified to run at 55mph.

It would probably mean they'd get awful paths to/from their depot, but if that's the cost of avoiding another Southall, I think it's worth it. I'm a little bit surprised the RAIB didn't include something along these lines in their recommendations. Technical solutions to eliminate risk are almost always better than human based ones.

 

[Sonik]

Another report into an incident where fatigue has played its role yet again. Yet NR, TOCs and FOCs are constantly after "productivity" which invariably translates as longer shift, shorter breaks and tighter rostering.

As a layperson, I'm quite shocked that drivers hours are not more tightly regulated. The driver in this incident was rostered for nearly 80 hours before rest day. You don't need a fancy risk model to see that might be an issue.

Fatigue is particularly risky for OTP operations, due to consistently working antisocial hours and irregular routes (and in this particular case, poor braking performance)

 

[the sniper]

Indeed, I wont spoil the movie for anyone but hopefully fatigue and rostering will finally start to be taken seriously.

Very seriously, I'm sure. The RSSB will have to make another RED video about not booking on tired, say, at 0300 when you've come off Lates just over 24hrs ago...

 

[GalaxyDog]

Very seriously, I'm sure. The RSSB will have to make another RED video about not booking on tired, say, at 0300 when you've come off Lates just over 24hrs ago...

Have read this with great interest as some weeks ago on a day out, I saw two 66s working a bonkers-length train consisting of ballsting equipment, ballast wagons and tampers to the point it took up two block sections in the area I was visiting.

I can't speculate on braking distances, driver input or other factors mentioned here as I'm not a driver, but can appreciate how long hours driving can cause mental fatigue. The one thing I can comment on is indeed fatigue for traincrew of all levels, brought up by the quoted post. This is more regular than you may think where the crossover is less than thirty hours between shifts. I know a colleague who booked on on three, perhaps fours sleep a night as he had been rostered on the two earliest jobs repeatedly in a four day week, coming straight off a week of the latest nights thanks to both master link and spare turns going sour. An accident waiting to happen and I suspect as long as rostering and diagramming continues this way in a "oh oh oh but it's legal!" without due care to reality then we will have swiss cheese poentials for accidents and worse.

 

[TheEdge]

As a layperson, I'm quite shocked that drivers hours are not more tightly regulated. The driver in this incident was rostered for nearly 80 hours before rest day. You don't need a fancy risk model to see that might be an issue.

In theory they are. I reckon that this sort of thing is far more common in the world of OTMs and permanent way works than in the more rigid timetabled passenger and freight world. However there are ways to work around the hours, either by design or just by poor rostering. Make that roster roll over two calendar weeks and then that 80 hours straight magically becomes two 40 hour runs and is a-ok according to the spreadsheet.

Very seriously, I'm sure. The RSSB will have to make another RED video about not booking on tired, say, at 0300 when you've come off Lates just over 24hrs ago...

You forgot the part where we should tell our manager and not sign on if we are too tired!

An accident waiting to happen and I suspect as long as rostering and diagramming continues this way in a "oh oh oh but it's legal!" without due care to reality then we will have swiss cheese poentials for accidents and worse.

The "oh oh oh but its legal" issue is that more and more as every roster and diagram pushes right up to the boundary of "its legal" there is just less and less wiggle room and IMO the issues of fatigue are going to get worse and worse. Then of course there is "to the letter of the law, not the spirit of the law", which can lead to some very nasty diagrams and rostering. At my TOC we recently had a diagram come out that was technically legal but was going to be an utter pig to work for various reasons plus some other issues. It was legal, however luckily both the union reps and local managers saw it and decided they really didn't want it to make it into the roster and pushed back.

 

[edwin_m]

It already exists in some areas and there's no fundamental technical reason why it couldn't be implemented everywhere (albeit modifying old mechanical or relay based interlockings would be "interesting").

The reason why it's not done everywhere is that it would significantly reduce capacity and would essentially break a lot of timetables. You'd have to completely rewrite them with higher junction margins and in many cases that would necessitate reducing frequencies.

As always, it's a question of cost vs benefit (or risk vs reward, if you prefer). Double red protection is probably justified in certain cases, such as trains with a lower braking rate than is assumed by the TPWS calculations. But not for every single train, considering that on most lines the vast majority of traffic consists of high-performing multiple units.

Alternatively I think it would be reasonable to limit poorly braked trains to a lower speed limit. I'm honestly quite surprised that a 4.6%g rated rail grinder was certified to run at 55mph.

It would probably mean they'd get awful paths to/from their depot, but if that's the cost of avoiding another Southall, I think it's worth it. I'm a little bit surprised the RAIB didn't include something along these lines in their recommendations. Technical solutions to eliminate risk are almost always better than human based ones.

In this case the risk is occasional instances of situations such as Sileby, and the reward is being able to run the timetables we now have with the resilience we now have (which some would argue is not enough). It's easy enough to propose a mitigation that would have prevented a particular incident, but much more difficult to say if that is a proportionate response to the hazard or indeed to confirm that it doesn't give rise to a different hazard. For example driver anticipation of approach controlled signals has been a concern for many years, and might get worse if there were more of them.

A proportionate response might be a signaller instruction to apply double reds manually to trains with reduced braking on the approach to junctions. Just doing it for a few trains would reduce the capacity penalty, but if done in the interlocking it would apply to all trains. However, it would increase signaller workload and would not be possible on older installations where some automatic signals can't be replaced to red.

 

[GC class B1]

In this case the risk is occasional instances of situations such as Sileby, and the reward is being able to run the timetables we now have with the resilience we now have (which some would argue is not enough). It's easy enough to propose a mitigation that would have prevented a particular incident, but much more difficult to say if that is a proportionate response to the hazard or indeed to confirm that it doesn't give rise to a different hazard. For example driver anticipation of approach controlled signals has been a concern for many years, and might get worse if there were more of them.

A proportionate response might be a signaller instruction to apply double reds manually to trains with reduced braking on the approach to junctions. Just doing it for a few trains would reduce the capacity penalty, but if done in the interlocking it would apply to all trains. However, it would increase signaller workload and would not be possible on older installations where some automatic signals can't be replaced to red.

The report confirmed that the Railgrinder brake performance was compliant with the stopping distances specified in Appendix A of GM/RT2045 issue 4. As it is clear that the signalling distances were adequate for a train braked in accordance with Appendix A, i do not think signallers would see it necessary to double block this train any more than for any other train (freight) that is braked in accordance with this Appendix.

 

[Quakkerillo]

[...] As proven by the fact they now have two RAIB reports to their name!
[...]

Just to clarify, where did you conclude they no have two RAIB reports? The report 06/2022 mentions the only other failure by this driver in section 29, referring to section 89. This was a SPAD in 2012 due to a misread signal, which was only internally investigated by the industry. RAIB reviewed the investigation, but didn't take any action themselves or write a report.
The report mentioned in section 90 is from 2020 with another driver at another company. So I'm curious why you're now claiming this driver is a known RAIB 'offender' as a fact.

 

[1E67]

Just to clarify, where did you conclude they no have two RAIB reports? The report 06/2022 mentions the only other failure by this driver in section 29, referring to section 89. This was a SPAD in 2012 due to a misread signal, which was only internally investigated by the industry. RAIB reviewed the investigation, but didn't take any action themselves or write a report.
The report mentioned in section 90 is from 2020 with another driver at another company. So I'm curious why you're now claiming this driver is a known RAIB 'offender' as a fact.

 

[XAM2175]

That says the railway's internal investigation was reviewed by the RAIB, not that the RAIB investigated it themselves. The driver thus doesn't have two "RAIB reports" to their name - but it would be fair to say that they had previously been involved in an incident that had come to the attention of the RAIB.

 

[HSTEd]

Ultimately such accidents will continue to occur until proper train protection systems are fitted in place of TPWS.

So.... bring on the ETCS deployment?

 

[GC class B1]

Ultimately such accidents will continue to occur until proper train protection systems are fitted in place of TPWS.

So.... bring on the ETCS deployment?

I am not an expert in signalling however having carefully considered the content of the report and document RIS-0775-CCS issue 3, I am of the opinion that had the OSS loops beeen positioned about 475 or 500 metres before the red signal the conflict may have been avoided. In summary I believe that the existing TPWS technology, although not able to prevent the SPAD may have prevented the conflict.
There may of course be a reason why the OSS loops were positioned much closer than 475 metres from the signal.

 

[Surreytraveller]

In this case the risk is occasional instances of situations such as Sileby, and the reward is being able to run the timetables we now have with the resilience we now have (which some would argue is not enough). It's easy enough to propose a mitigation that would have prevented a particular incident, but much more difficult to say if that is a proportionate response to the hazard or indeed to confirm that it doesn't give rise to a different hazard. For example driver anticipation of approach controlled signals has been a concern for many years, and might get worse if there were more of them.

A proportionate response might be a signaller instruction to apply double reds manually to trains with reduced braking on the approach to junctions. Just doing it for a few trains would reduce the capacity penalty, but if done in the interlocking it would apply to all trains. However, it would increase signaller workload and would not be possible on older installations where some automatic signals can't be replaced to red.

I hardly think giving someone else who's doing shift work extra workload is a proportionate response. Just introducing the possibility of someone else making an error. That's assuming the signal in rear is a controlled signal

 

[the sniper]

You forgot the part where we should tell our manager and not sign on if we are too tired!

That's the one. I know a Guard who followed the advice once, it seemed to trigger a process similar to being sectioned under the Mental Health Act...

Funnily enough, in a messroom at 5am, it was rather like something from 'One Flew Over the Cuckoo's Nest'.

 

[MarkyT]

Part of the problem with UKs very basic cab warning and protection systems (AWS/TPWS) is, if you successfully pass a magnet or grid without being tripped (after acknowledgment in the case of AWS), they impose no ongoing control on speed, so after an AWS warning you can go on to increase your speed. Similarly if you pass under an OSS speed trap on approach to a red then you can again accelerate, possibly sufficient to exceed the protection capability provided by the subsequent TSS at the red signal. Even some fairly old systems in other countries can provide ongoing protection after similar events. 'Indusi' (or PZB (Punktförmige Zugbeeinflussung) in Germany applies ongoing restricted speed conditions for a fixed distance after getting a distant warning or passing under an OSS equivalent transponder on approach to a red. More sophisticated modern UK trains might implement similar controls after receiving TPWS and AWS warnings. For details of Indusi see here:

Indusi (Part 1)

www.sh1.org

"Indusi" is an acronym derived from "Induktive Signalsicherung", or Inductive Signal Protection. The official term is PZB, for Punktförmige Zugbeeinflussung, "spot-wise train control", as opposed to Linienzugbeeinflussung (LZB), linear train control.

The Indusi was introduced in 1934, most signals still were wire-operated semaphores, so the trackside magnets do not need power supply. The idea is to prevent running a red signal under almost any circumstance.

 

[edwin_m]

The report confirmed that the Railgrinder brake performance was compliant with the stopping distances specified in Appendix A of GM/RT2045 issue 4. As it is clear that the signalling distances were adequate for a train braked in accordance with Appendix A, i do not think signallers would see it necessary to double block this train any more than for any other train (freight) that is braked in accordance with this Appendix.

I'm not familiar with that standard. However, the report did say that the TPWS design was intended to stop a train before the point of conflict provided it could decelerate at 7.5%g or more, and this train couldn't achieve that.

Part of the problem with UKs very basic cab warning and protection systems (AWS/TPWS) is, if you successfully pass a magnet or grid without being tripped (after acknowledgment in the case of AWS), they impose no ongoing control on speed, so after an AWS warning you can go on to increase your speed. Similarly if you pass under an OSS speed trap on approach to a red then you can again accelerate, possibly sufficient to exceed the protection capability provided by the subsequent TSS at the red signal. Even some fairly old systems in other countries can provide ongoing protection after similar events. 'Indusi' (or PZB (Punktförmige Zugbeeinflussung) in Germany applies ongoing restricted speed conditions for a fixed distance after getting a distant warning or passing under an OSS equivalent transponder on approach to a red. More sophisticated modern UK trains might implement similar controls after receiving TPWS and AWS warnings. For details of Indusi see here:

Indusi (Part 1)

www.sh1.org

Interesting thought. I guess a modern system could remember the speed at passing the OSS and the time difference between the loops to deduce the set speed, and restrict the train to that speed for a certain period afterwards.

 

[MarkyT]

Interesting thought. I guess a modern system could remember the speed at passing the OSS and the time difference between the loops to deduce the set speed, and restrict the train to that speed for a certain period afterwards.

That was my thinking. A forced deceleration could also apply after an AWS warning.

 

[GC class B1]

I'm not familiar with that standard. However, the report did say that the TPWS design was intended to stop a train before the point of conflict provided it could decelerate at 7.5%g or more, and this train couldn't achieve that.

I have considered this point in my post no 54.