How common are serious wheelslide incidents?

[DerekC]

Moderator note: Split from

Collision and derailment near Salisbury (Fisherton Tunnel) 31/10/21

Mod note: Please take care when posting; any speculation should be reasonable, proportional and clearly identified as such. As this incident is being reported in the mainstream media, we need to ensure speculation posted here isn't picked up and reported as fact. Additionally, this is a...

www.railforums.co.uk

We should be careful that we don't rush to judgement on this one. RAIB made it clear that they will be looking at train braking system function and performance as well as wheel/rail adhesion.

And the wider safety context has to be considered, too. I don't want to sound uncaring - it must have been a very traumatising event even for those who weren't injured, but how many injuries and fatalities have been down to wheel slide over the past thirty years, and does the risk justify spending squillions of pounds on fitting track brakes or eddy current brakes?

How does the benefit compare with (for example) spending the same money on road safety? That's the cold, hard calculation that has to be done.

 

[Annetts key]

How does the benefit compare with (for example) spending the same money on road safety? That's the cold, hard calculation that has to be done.

Or spending a relatively small amount of money on improved vegetation control and more RHTT?

 

[MarkyT]

We should be careful that we don't rush to judgement on this one. RAIB made it clear that they will be looking at train braking system function and performance as well as wheel/rail adhesion. And the wider safety context has to be considered, too. I don't want to sound uncaring - it must have been a very traumatising event even for those who weren't injured, but how many injuries and fatalities have been down to wheel slide over the past thirty years, and does the risk justify spending squillions of pounds on fitting track brakes or eddy current brakes? How does the benefit compare with (for example) spending the same money on road safety? That's the cold, hard calculation that has to be done.

Equally, if wider policy envisages significant mode shift from road to rail then such safety improvements could be a good investment.

 

[21C101]

We should be careful that we don't rush to judgement on this one. RAIB made it clear that they will be looking at train braking system function and performance as well as wheel/rail adhesion. And the wider safety context has to be considered, too. I don't want to sound uncaring - it must have been a very traumatising event even for those who weren't injured, but how many injuries and fatalities have been down to wheel slide over the past thirty years, and does the risk justify spending squillions of pounds on fitting track brakes or eddy current brakes? How does the benefit compare with (for example) spending the same money on road safety? That's the cold, hard calculation that has to be done.

It is a fair comment, but rememember we were only, by the grace of God, a minute or two from a three train head on in the middle of a tunnel.

In some ways this was a "near miss" for a ladbroke/clapham scale disaster. We may not be so lucky next time.

 

[dciuk]

In some ways this was a "near miss" for a ladbroke/clapham scale disaster. We may not be so lucky next time.

Had 1F30 been running to time, would we even be aware 1L53 over-running the signal, even though it would still have been a near miss with 1F27, and how frequently do these near misses occur? The only one I can think of is Wootton Bassett.

 

[w0033944]

It is a fair comment, but rememember we were only, by the grace of God, a minute or two from a three train head on in the middle of a tunnel.

In some ways this was a "near miss" for a ladbroke/clapham scale disaster. We may not be so lucky next time.

Yes, I'm surprised that a senior member on a rail forum would have such a casual viewpoint on safety matters. Just because the railway got away with it this gime does not mean that the problem isn't important or that we can sit back complacently.

 

[alxndr]

Had 1F30 been running to time, would we even be aware 1L53 over-running the signal, even though it would still have been a near miss with 1L27, and how frequently do these near misses occur? The only one I can think of is Wootton Bassett.

Wootton Bassett isn't exactly comparable due to the isolation of the braking systems. Had it not been isolated then perhaps they would have still SPADed and had a near miss, but perhaps not. It seems far more unlikely when the conflict point in question there was 500 m.

The main difference though is that Wootton Bassett might not have happened if not for the reckless actions and attitude, whereas, as it seems in this instance, the driver did everything right but was let down by physics.

 

[dciuk]

Wootton Bassett isn't exactly comparable due to the isolation of the braking systems. Had it not been isolated then perhaps they would have still SPADed and had a near miss, but perhaps not. It seems far more unlikely when the conflict point in question there was 500 m.

The main difference though is that Wootton Bassett might not have happened if not for the reckless actions and attitude, whereas, as it seems in this instance, the driver did everything right but was let down by physics.

I was not trying to compare the reasons for the near miss, more the fact they were near misses and wondered how common near misses are. Are they often happening? Also outside of this forum has the media picked up on the near miss with 1F27?

 

[Cowley]

Also outside of this forum has the media picked up on the near miss with 1F27?

They don’t really seem to have but then the news cycle seems to have moved on fairly quickly anyway this week and perhaps with the confusion around the initial reports they were happy just to have got what had happened worked out and left it at that?
In some ways the way that the facts took a while to come out probably helped the railway PR wise.

 

[tonysk14]

They don’t really seem to have but then the news cycle seems to have moved on fairly quickly anyway this week and perhaps with the confusion around the initial reports they were happy just to have got what had happened worked out and left it at that?
In some ways the way that the facts took a while to come out probably helped the railway PR wise.

Hope it's ok to post this. But very interesting video here.

 

[Llama]

I can think of two incidents in recent years where the driver has pressed the GSMR REC button during a severe wheelslide/loss of adhesion while on a fairly steep falling gradient approaching a signal at danger protecting a fairly busy junction where a train approaching from the other direction could be proceeding at 50mph. Both were at the same location. No significant devegetation has taken place. The area is a known poor adhesion location but is not 'listed' in the sectional appendix. Also communication of these incidents to other drivers has been poor - a lot of drivers aren't even aware these incidents ever happened.

 

[O L Leigh]

I suppose it depends on how you want to justify spending the money. If you're going to put a price on a "Lives Saved" basis then yes it probably is an excessive spends. However, if you're looking to foster public confidence in the rail network as part of a wider drive to encourage it's use, then having incidents like this and weathering the news coverage that it garners is not going to be a great idea.

How often do these sorts of incidents happen? More than you might realise. That they aren't newsworthy is hardly the point because, as has been said already, we have come close to having more collisions due to wheelslide and only got away with it by good fortune.

 

[millemille]

You don't need to spend money on eddy current or magnetic track brakes.

Dual Variable Rate Sanders allow trains to stop at 6%g (actually slightly higher than that, but basically brake step 2 stopping performance) whatever the adhesion levels. RSSB research project T1107, in testing at Old Dalby test track using a GWR class 387 and the service pilot with DVRS equipment fitted to WMT 323's on closed track testing and in service, has proved that the concept and technology works and the WMT drivers who experienced the sanders working in anger loved it.

VID-20191020-WA0003

This is "VID-20191020-WA0003" by Michael Milhinch on Vimeo, the home for high quality videos and the people who love them.

vimeo.com

I should declare an interest here; my company designed, manufactured, installed and supported the DVRS pilot sanding equipment (it's me you can see opening the sander filler in the BBC footage in the video)

The intent is that a whole fleet will be fitted with DVRS for leaf fall 2023 and this will prove on a whole fleet level, when exposed to all driving ability and other human factors and the variability of normal service operations, that DVRS significantly reduces or eliminates leaf fall season incidents and delays.

In terms of the OP's question, it varies from operator to operator. Two comparable operators, in terms of number of trains in service every day, I work with have around 5 over runs (from missing the monitors to full blown SPAD's) directly attributed to low adhesion every leaf fall season while another has over 50.

But you need to be sure you are comparing apples to apples and oranges to oranges, train length vs. platform length being a prime example.