Rail safety improvements over the past 10 years

[thenorthern]

The other day I was looking at the list of rail crashes in the United Kingdom and one thing I noticed that almost every year until 2007 there was a serious accident on the railways and in the early days of privatization there were a large number of serious crashes such as Ladbroke Grove, Selby and Ufton Nervet.

Since Grayrigg in 2007 however I don't think there has been a crash where a passenger has been killed aboard a train and the numbers of crashes at level crossing seem to be declining as well.

I was wondering however what this is down to is it that safety technology is improving or that Network Rail is getting stricter with safety regulations?

 

[edwin_m]

The biggest single change has been TPWS, which came in slightly before your timeframe but would have prevented Ladbroke Grove and possibly Southall had it been fitted at the time.

Other than that I'd say it's the cumulative effect of a wide range of smaller and more gradual programmes:
- Network Rail starting to get on top of track maintenance issues (cause of Hatfield, Potters Bar, Grayrigg)
- Elimination of level crossings (Ufton Nervet is now planned to be eliminated but many remain and this is now the number 1 source of risk on the railway)
- Construction of barriers at high risk sites for road vehicle incursion (Great Heck ("Selby"))

There's also a tightening of safety standards and culture which would probably have prevented Southall if it had been applied at the time, and maybe also Ladbroke Grove. But I think most of the benefit actually comes from technical measures such as those I mentioned above.

 

[dk1]

Totally agree that TPWS has seen a massive change in UK rail safety. Has to be way up there as one of the best inventions of all time on this countries railway network. Seems hugely understated to me. We should also publicise our safety record more to get it through to people what strides we have made. You only have to read railway publications from the 70s/80s to realise that there where often several collision or accident incidents per issue to realise how times have changed for the better.

 

[Marklund]

Totally agree that TPWS has seen a massive change in UK rail safety. Has to be way up there as one of the best inventions of all time on this countries railway network. Seems hugely understated to me.

Because of the reliability of the early modules, changes, movement of loops at the beginning, etc., they were never seen in good light.

As the system has matured, it's turned out to have been a very worthwhile investment.

 

[DerekC]

TPWS is certainly the biggest recent change - but we need to remember that it works because it is plugging the last real loophole in a system of safe control which has progressively improved since about 1870. Privatisation seems to have made virtually no difference to the trend. Moving train accidents are now a very small proportion of the overall risk.

 

[Dave1987]

Driver training and attitudes towards operational incidents has also vastly changed. In the past a SPAD wasn't a big deal, but now every single TPWS activation is treated as a safety of the line incident and investigated. Attitudes and training along with AWS/TPWS have contributed massively towards the great safety records that the railway has.

 

[thenorthern]

Network Rail seems to literally have safety as its number one priority which many companies can claim to do but in this case it is definitely true. Railtrack PLC on the other hand had a bad reputation for safety.

TPWS has been a very good system but looking at other things as well such as trains staying upright if they derail, stronger trains, a complete and strictly enforced ban on being near the tracks except as level crossings and rolling stock having to meet strict safety tests.

Its not just railway disasters though since the 1980s major disasters with large amount of fatalities in this country have now largely been confined to history as its hard to remember in the 1980s there were many serious disasters such as the Herald of Free Enterprise disaster and the Papa Alpha disaster both of which killed over 100 people.

 

[westv]

I'm sure you meant to say Piper Alpha.

 

[thenorthern]

Driver training and attitudes towards operational incidents has also vastly changed. In the past a SPAD wasn't a big deal, but now every single TPWS activation is treated as a safety of the line incident and investigated. Attitudes and training along with AWS/TPWS have contributed massively towards the great safety records that the railway has.

Very true look at the incident with West Coast Railways last year with a SPAD which admittedly was a serious SPAD but nevertheless Network Rail suspended all West Coast Railway trains because of it.

I'm sure you meant to say Piper Alpha.

Indeed I did.

 

[MarlowDonkey]

TPWS has been a very good system but looking at other things as well such as trains staying upright if they derail, stronger trains, a complete and strictly enforced ban on being near the tracks except as level crossings and rolling stock having to meet strict safety tests.

A couple of thoughts on Southall and marginally contributory factors.
Why was it permitted to turn the train and run without the safety system? But why was it acceptable to signal a freight train to cross in front of a 125 mph passenger train?

Railtrack lost control of its network and the state of repair or otherwise.

 

[JN114]

A couple of thoughts on Southall and marginally contributory factors.
Why was it permitted to turn the train and run without the safety system? But why was it acceptable to signal a freight train to cross in front of a 125 mph passenger train?

Railtrack lost control of its network and the state of repair or otherwise.

On Southall - running the train without AWS or ATP was a TOC failing (which they were suitably penalised for), not Railtrack.

As for crossing a freight in front of a 125mph passenger train, why not? It was protected by the signalling system, and is a move that happens all across the country dozens of times a day. The railway would literally grind to a halt if that (and thus any similar) scenario wasn't permitted.

 

[headshot119]

A couple of thoughts on Southall and marginally contributory factors.
Why was it permitted to turn the train and run without the safety system? But why was it acceptable to signal a freight train to cross in front of a 125 mph passenger train?

Railtrack lost control of its network and the state of repair or otherwise.

Because both trains where protected by the signalling system, the railway simply would not work if you stopped allowing slower trains to cross in front of faster ones.

 

[83G/84D]

Don't forget the importance of the GSM-R system, a great aid to drivers and signalling staff.

 

[edwin_m]

Don't forget the importance of the GSM-R system, a great aid to drivers and signalling staff.

Yes indeed, most recently demonstrated by the Watford Tunnel incident. According to RAIB, the driver of the derailed train used the emergency button and the driver of the second train was able to reduce speed considerably before the impact.

 

[infobleep]

When did TWPS come. Into being?

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[dk1]

When did TWPS come. Into being?

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According to Wikipedia it was rolled out from 2003. I was going to say 2005 but that may have been when it started to make a bigger impact. My first dealings where with it around that time when I was accused of being late to cancel the AWS when it turned out to be an issue with an overspeed sensor. There was no OTMR fitted then so couldn't be proved either way apart from I knew it was not the AWS.

 

[AM9]

According to Wikipedia it was rolled out from 2003. I was going to say 2005 but that may have been when it started to make a bigger impact. My first dealings where with it around that time when I was accused of being late to cancel the AWS when it turned out to be an issue with an overspeed sensor. There was no OTMR fitted then so couldn't be proved either way apart from I knew it was not the AWS.

I have a vague memory of TPWS introduction on the MML being one of the first. Wasn't there talk of it being a poor alternative to ATP, including only being effective below 75mph?

 

[dk1]

I have a vague memory of TPWS introduction on the MML being one of the first. Wasn't there talk of it being a poor alternative to ATP, including only being effective below 75mph?

It was deemed the affordable option & has proven it's worth.

 

[Marklund]

I have a vague memory of TPWS introduction on the MML being one of the first. Wasn't there talk of it being a poor alternative to ATP, including only being effective below 75mph?

Fairly sure the first training video we were shown was filmed on the MML with a 319.

In fact, someone has uploaded it to YouTube.

 

[Peter Mugridge]

Wasn't there talk of it being a poor alternative to ATP, including only being effective below 75mph?

If I remember correctly, it will stop a train from 75mph within the overlap.

Thus if a train is going faster, it will clearly not be stopped within the overlap, but equally clearly any impact beyond that point would be considerably reduced from what it would be without TPWS.

Therefore even in those circumstances where it does not prevent an accident, it will at least considerably reduce the severity of the accident.

Whether the 75mph figure is correct or not or if the overlap distance is correct or not, the principle will still apply - any accident which is not prevented by the TPWS will be much less serious than it would otherwise.

 

[Marklund]

Whether the 75mph figure is correct or not or if the overlap distance is correct or not, the principle will still apply - any accident which is not prevented by the TPWS will be much less serious than it would otherwise.

TPWS+ raises this to 100 mph. It's just an additional set of OSS loops.

 

[W230]

Wasn't there talk of it being a poor alternative to ATP, including only being effective below 75mph?

I'd always understood the 75mph statement to be an urban myth. Ultimately it works by timing how long the train takes to cover the distance between the arming and trigger loop. I can't see why by moving these further away from a signal and adjusting the trigger speed as required would no have the desired effect.

As mentioned though, they certainly don't stop all SPADS occurring but they do reduce the number and they certainly reduce the outcome.

 

[edwin_m]

I was the minute-taker and general gopher for the SPAD Reduction and Mitigation committee, joint between BR and Railtrack, that came up with the idea of TPWS in around 1994. An analysis was done on accidents back to about 1968, looking at each one and estimating what the outcome would have been had one of a number of alternatives existed that didn't exist at the time. This concluded that TPWS would avoid about 70% of the casualties that ATP would avoid, at lower cost and with quicker fitment. Subsequent experience has largely borne this out.

As mentioned above, a single overspeed sensor will stop a passenger train from about 75mph within a standard overlap, but the second sensor on TPWS+ improves this speed, and even if it doesn't stop within the overlap the severity of any collision will be much less. I think the basic technology will successfully detect the loops and apply the brake at any speed trains might conceivably attain.

 

[headshot119]

I'd always understood the 75mph statement to be an urban myth. Ultimately it works by timing how long the train takes to cover the distance between the arming and trigger loop. I can't see why by moving these further away from a signal and adjusting the trigger speed as required would no have the desired effect.

As mentioned though, they certainly don't stop all SPADS occurring but they do reduce the number and they certainly reduce the outcome.

The 75mph isn't an urban myth, remember when TPWS came in it was designed solely to stop a train in the overlap of the signal IF it pass the signal at danger. Hence the TSS grids are right at the signal, and only armed if the signal is at danger. Go through at 75MPH on a red and you'll stop in the overlap, any faster and you won't. Hence OSS was developed which checks your speed on approach to a signal, or speed restriction.

TPWS was never designed as a way to stop SPADs, only to mitigate the risk from one occurring.

 

[infobleep]

I was the minute-taker and general gopher for the SPAD Reduction and Mitigation committee, joint between BR and Railtrack, that came up with the idea of TPWS in around 1994. An analysis was done on accidents back to about 1968, looking at each one and estimating what the outcome would have been had one of a number of alternatives existed that didn't exist at the time. This concluded that TPWS would avoid about 70% of the casualties that ATP would avoid, at lower cost and with quicker fitment. Subsequent experience has largely borne this out.

As mentioned above, a single overspeed sensor will stop a passenger train from about 75mph within a standard overlap, but the second sensor on TPWS+ improves this speed, and even if it doesn't stop within the overlap the severity of any collision will be much less. I think the basic technology will successfully detect the loops and apply the brake at any speed trains might conceivably attain.

Did it take 9 years to design and start to be fitted?

Was ATP in wide spread use before it?

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[QueensCurve]

Privatisation seems to have made virtually no difference to the trend.

Not disputing that the railways are safer than ever, nor intending to oppose or support privatisation.

There was a cluster of major accidents in the years immediately following privatisation

• Track defect at Hatfield
• SPAD at Southall
• SPAD at Ladbroke Grove.
• Track defect at Potters Bar

These have arguably not amounted to a trend, but the years coincided with a big increase in the number of SPADs. They also coincided with outsourcing of maintenance and renewals.

All this seems to have been improved beyond recognition since NR took over from Railtrack.

I consider the profit motive out of infrastructure management may have been a factor, certainly with regard to the track issues.

 

[thenorthern]

Not disputing that the railways are safer than ever, nor intending to oppose or support privatisation.

There was a cluster of major accidents in the years immediately following privatisation

• Track defect at Hatfield
• SPAD at Southall
• SPAD at Ladbroke Grove.
• Track defect at Potters Bar

These have arguably not amounted to a trend, but the years coincided with a big increase in the number of SPADs. They also coincided with outsourcing of maintenance and renewals.

All this seems to have been improved beyond recognition since NR took over from Railtrack.

I consider the profit motive out of infrastructure management may have been a factor, certainly with regard to the track issues.

I would agree the privatization of Railtrack PLC definitely had a major negative impact on safety as Railtrack PLC found itself in a strange situation where it was reliant on Government money and unlike with the TOCs it wasn't carrying passengers so there wasn't an incentive for it to increase passenger numbers. Also unlike TOCs there was no franchise period so if it performed poorly it wasn't the case after so many years the Government would just award the contract to someone else.

In the end it seems the way they saved money was to cut back on maintenance which had a negative impact on safety.

 

[Railsigns]

The original TPWS fitment programme ran from 1999 to 2004 with the aim of fitting TPWS across the whole network within a short timescale. To keep timescales to a minimum, this TPWS was installed according to a simple set of principles that didn't provide comprehensive protection in every instance.

TPWS fitment nowadays involves a far more scientific approach that is always calculated to stop a train approaching at the maximum permissible speed within the 'safe overrun distance'. Note that the length of the safe overrun distance will usually exceed the length of the overlap. TPWS was never remitted to stop trains within the overlap.

 

[edwin_m]

Did it take 9 years to design and start to be fitted?

Was ATP in wide spread use before it?

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From memory a year or so to develop/evaluate the concept, then a couple more to develop the technology. It was then awaiting agreement and funding for several years (during which Ladbroke Grove happened, certainly TPWS preventable) before installation started. I think the nine years would actually take you about up to the end of installation.

ATP was then, as now, only fitted to GWML and Chiltern which were different and incompatible systems. Had we adopted it more widely then we would be in the same situation as many European countries, having to replace an existing national system with ERTMS.

 

[infobleep]

From memory a year or so to develop/evaluate the concept, then a couple more to develop the technology. It was then awaiting agreement and funding for several years (during which Ladbroke Grove happened, certainly TPWS preventable) before installation started. I think the nine years would actually take you about up to the end of installation.

ATP was then, as now, only fitted to GWML and Chiltern which were different and incompatible systems. Had we adopted it more widely then we would be in the same situation as many European countries, having to replace an existing national system with ERTMS.

So in other words politics stopped it from happening sooner and less politics might have saved lives. Or is that an unfair thing to say. I'm an outsider.

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