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

[LAX54]

thank you for posting the Raib preliminary findings.

what happened is what I had thought had happened.

Also would this not be a SPAR ( obviously dependant on where the driver applied the brakes, and how the WSP (wheel slip protection) acted).

A SPAR is where the signal goes back to red, and the driver has no chance in stopping, but this was red, and even though it slid past, it would still be a SPAD
Its scary how far a train can slide when conditions are right, or more correctly 'wrong'

 

[172007]

Nope, it’s a spad.
The signal was set at danger for a reason and had not been ‘put back’ to red.

A SPAR is due to a technical failure, not specifically or restrictive to a signal being placed back to red.

I would immagine if the driver had braked as per the professional driving policy I.e. placed the train into emergency at an appropriate timely place before the train past the signal at red then the driver will be exonerated and it would go down as a SPAR.

 

[Snow1964]

Entering the tunnel from the east there is a name board "Salisbury Tunnel". Entering it from the west (I.e. from the station) there is a name board "Fisherton Tunnel". I guess both names are valid ?

Fisherton is where the current Salisbury station is (the GWR line from Warminster had its own station at Fisherton Street opened in 1856. The Fisherton name comes from the connecting line that linked the rail lines to those in Laverstock & Milford area. When the line from Basingstoke first opened in 1857 trains ran along what is now the Laverstock spur, and backed into Milford Terminus. The connecting line through the tunnel opened slightly later in May 1859

I think the prefix (Salisbury) was to distinguish it from Southampton Tunnel Junction (where the junction with now lifted curve towards Southampton Terminus and Eastern Docks was). The LSWR couldn’t have two signal boxes both called Tunnel Junction. The Prefixes are cities where it is located, not named after actual tunnel.

The Romsey line fairly quickly encounters Laverstock south Junction, Milford Junction (where original line ran, later goods depot), and about 3 miles further on Alderbury Junction (which in later years served a short spur to a chalk quarry)

Sorry about off topic history lesson, but should explain the use of Salisbury and Fisherton names

 

[bengley]

I hate to prick the bubble of this tree bashing festival but if you look at the photo posted a few posts earlier

Link https://www.flickr.com/photos/96859208@N07/10873585803

you can see from the photo that by the time the SWR train had passed under the road bridge and entered the now tree infested cutting with junction and tunnel entrance, it will already have passed the red signal in question.

The mile or so that the train would have been braking on, from roughly the A30 overbridge at Hampton Inn to the signal in question is mostly embankment/level ground level and, as a look at google maps shows, not greatly tree or bush infested.

The RAIB have stated that wheelslide is a factor, but have not stated it is the root cause.

There are also other mitigations available for wheelslide other than a chainsaw orgy (see the clasp brakes on Thameslink class 700s for an example).

Doesn't mean the wheels weren't contaminated from further up the line. I don't know the area so can't comment on the route.

 

[Cheshire Scot]

Once TPWS activates a brake application, whether at the signal protecting the junction or indeed at the signal in rear of that, does this impact on the ability of the driver to attempt to bring the train under control?
My (laymans) assumption is that the braking is taken out of the drivers control by a TPWS intervention and the driver then cannot override TPWS unless perhaps by isolating it which, even if feasible, the time available to attempt this would presumably be minimal, plus of course the circumstances may well be alreay affecting the driver.

 

[VP185]

I’d imagine at that location the junction signal will have tpws and there will be OSS on approach to it. I doubt the signal that was showing the yellow would have anything as the line speed is only 50 mph (I don’t sign the route though so happy to be corrected).
If the train was already in a slide the TPWS would’ve been useless anyway.

I’d be interested to know if the emergency brake application caused by the TPWS intervention actually made the slide worse?

Once TPWS activates a brake application, whether at the signal protecting the junction or indeed at the signal in rear of that, does this impact on the ability of the driver to attempt to bring the train under control?
My (laymans) assumption is that the braking is taken out of the drivers control by a TPWS intervention and the driver then cannot override TPWS unless perhaps by isolating it which, even if feasible, the time available to attempt this would presumably be minimal, plus of course the circumstances may well be alreay affecting the driver.

Once TPWS intervenes with a emergency brake application the driver loses all control and is basically a passenger.

 

[2HAP]

Its scary how far a train can slide when conditions are right, or more correctly 'wrong'

2 mi 36 ch (3.94 km) in the case of Stonegate.

 

[Dan17H]

is that bridges and tunnels structures or train structures? I am guessing the former.

Structures mate

 

[Thumper1127]

Realtime Trains - 302C 1407 Eastleigh East Yard to Eastleigh East Yard

Realtime Trains is an independent source of live realtime running information for the Great British railway network.

www.realtimetrains.co.uk

I don't know if this is a RHTT, but it has the timetable characteristics of other trains I know that are... Whatever it was, it was due along the down line from Andover about 90 minutes before the incident, but appears to have been cancelled.

Yes, that’s one of the ones I referred to in my original post. As far as I’ve been able to ascertain there were no RHTT trains after Friday.

 

[SLF2021]

I was on IF27. We came to a halt just east of Salisbury. We were informed of an emergency, but that we were safe. I am a professional engineer, working in transport but not the rail industry. I do appreciate the specialist aspects of different forms of transport - thank you to the knowledgeable people here who have posted informed and reasoned views. We spent a considerable time stationary, but as the situation became clearer we all focussed our attention on those who were being rescued. Having seen the emerging information from the RAIB, I feel exceptionally lucky that our train was not running one minute later. I would like to take this opportunity to say thank you to the staff on our train. It must have been a very difficult, stressful and distressing time for them. Both the driver and guard were faultlessly professional, keeping us informed to the best that they could, and ensuring our safety.

 

[Signal Head]

I’d imagine at that location the junction signal will have tpws and there will be OSS on approach to it. I doubt the signal that was showing the yellow would have anything as the line speed is only 50 mph (I don’t sign the route though so happy to be corrected).
If the train was already in a slide the TPWS would’ve been useless anyway.

SY29 in rear also has TPWS (Trainstop and Overspeed) because of the conflict at Laverstock North Junction. The approach speed to that signal is 90, according to the Appendix. The 50 PSR towards Tunnel Junction begins at Laverstock North.

 

[GB]

A SPAR is due to a technical failure, not specifically or restrictive to a signal being placed back to red.

I would immagine if the driver had braked as per the professional driving policy I.e. placed the train into emergency at an appropriate timely place before the train past the signal at red then the driver will be exonerated and it would go down as a SPAR.

Even if the driver is exonerated it will still be recorded as a SPAD.

 

[Horizon22]

I was on IF27. We came to a halt just east of Salisbury. We were informed of an emergency, but that we were safe. I am a professional engineer, working in transport but not the rail industry. I do appreciate the specialist aspects of different forms of transport - thank you to the knowledgeable people here who have posted informed and reasoned views. We spent a considerable time stationary, but as the situation became clearer we all focussed our attention on those who were being rescued. Having seen the emerging information from the RAIB, I feel exceptionally lucky that our train was not running one minute later. I would like to take this opportunity to say thank you to the staff on our train. It must have been a very difficult, stressful and distressing time for them. Both the driver and guard were faultlessly professional, keeping us informed to the best that they could, and ensuring our safety.

Glad to hear that. Being stationary in itself can be somewhat unnerving for a long period of time without reassurance from crew.

 

[Dave W]

Yes, that’s one of the ones I referred to in my original post. As far as I’ve been able to ascertain there were no RHTT trains after Friday.

Apologies - should have gone back to find it. Thanks for confirming.

 

[backontrack]

So am I right in saying this technically was a SPAD? Red light comes on, SWR driver (or TPWS) brakes, braking system fails due to low adhesion, SWR ploughs into GWR. Is that how it went down? Or would 'SPAR' be more appropriate?

 

[Snow1964]

This is another historic photo of the junction (looking away from the tunnel) in 1970.

The chalky cutting has no trees, and there aren’t any in the allotments.

Trees don’t actually grow very well in what is mainly chalk cutting with virtually no topsoil

70 094 290470 Salisbury Tunnel Junction DMU 1103

Not an expert on Southern DMU's, this one is at Salisbury Tunnel Junction on the 29th of April 1970 on the 13.08 Portsmouth to Salisbury service.

www.flickr.com

From KDH archive

 

[bengley]

So am I right in saying this technically was a SPAD? Red light comes on, SWR driver brakes, braking system fails due to low adhesion, SWR ploughs into GWR. Is that how it went down?

Sort of. A red light doesn't just come on, but the driver would have probably received a signal or two before the red one to warn him to slow and be prepared to stop

 

[SLF2021]

Glad to hear that. Being stationary in itself can be somewhat unnerving for a long period of time without reassurance from crew.

Thank you. I’m not sure of the reasons, but a PA announcement on our train told us that we had been involved in an incident and that the emergency services were on the way. I guess it was an automated process! Logic suggested that we were safe, but you don’t know what you don’t know…

 

[Need2]

Even if the driver is exonerated it will still be recorded as a SPAD.

Correct.
Unless the signal was put back or there was an irrefutable defect with the train, it will be recorded as a SPAD.

 

[AndyPJG]

I was on IF27. .......I would like to take this opportunity to say thank you to the staff on our train. It must have been a very difficult, stressful and distressing time for them. Both the driver and guard were faultlessly professional, keeping us informed to the best that they could, and ensuring our safety.

maybe email to GWR? I'm sure that would be appreciated by the crew.

 

[SLF2021]

maybe email to GWR? I'm sure that would be appreciated by the crew.

Already done!

 

[Surreytraveller]

thank you for posting the Raib preliminary findings.

what happened is what I had thought had happened.

Also would this not be a SPAR ( obviously dependant on where the driver applied the brakes, and how the WSP (wheel slip protection) acted).

Its a SPAD. The train was expected to stop at the signal, the signal was always at red for that train.
A SPAR would, for example, be where a signal was replaced to danger due to error, a fault or in an emergency after the train had already passed green signals on the approach and the driver would be expecting to come across a proceed aspect

 

[Railsigns]

Surely that's the reason that there are yellow and in some places double yellow signals?

No. Yellow and double yellow aspects are there to give drivers the braking distance they need to stop at a red signal ahead. They do nothing to increase the separation between trains.

 

[Thumper1127]

I was on IF27. We came to a halt just east of Salisbury. We were informed of an emergency, but that we were safe. I am a professional engineer, working in transport but not the rail industry. I do appreciate the specialist aspects of different forms of transport - thank you to the knowledgeable people here who have posted informed and reasoned views. We spent a considerable time stationary, but as the situation became clearer we all focussed our attention on those who were being rescued. Having seen the emerging information from the RAIB, I feel exceptionally lucky that our train was not running one minute later. I would like to take this opportunity to say thank you to the staff on our train. It must have been a very difficult, stressful and distressing time for them. Both the driver and guard were faultlessly professional, keeping us informed to the best that they could, and ensuring our safety.

I was on IF27. We came to a halt just east of Salisbury. We were informed of an emergency, but that we were safe. I am a professional engineer, working in transport but not the rail industry. I do appreciate the specialist aspects of different forms of transport - thank you to the knowledgeable people here who have posted informed and reasoned views. We spent a considerable time stationary, but as the situation became clearer we all focussed our attention on those who were being rescued. Having seen the emerging information from the RAIB, I feel exceptionally lucky that our train was not running one minute later. I would like to take this opportunity to say thank you to the staff on our train. It must have been a very difficult, stressful and distressing time for them. Both the driver and guard were faultlessly professional, keeping us informed to the best that they could, and ensuring our safety.

Thank you for highlighting the professional, and instinctive, conduct of the staff. It is ingrained in true rail professionals and long may it continue. Being ex rail industry, and relatively local to the area, I can say that what always stayed with me during my career was the way staff always rally when things go wrong. Often not seen or appreciated. So thank you for your factual and unsensational posting, it will mean a lot to those in the industry.

 

[WestRiding]

Its a SPAD. The train was expected to stop at the signal, the signal was always at red for that train.
A SPAR would, for example, be where a signal was replaced to danger due to error, a fault or in an emergency after the train had already passed green signals on the approach and the driver would be expecting to come across a proceed aspect

If, and I stress IF, it was caused by Leaf Fall, what is in place to try taking it into account? Do drivers drive differently regarding technique in Autumn?

 

[LAX54]

Surely that's the reason that there are yellow and in some places double yellow signals?

Does not stop a slide though, you can ease off at the DY and SY, and if the conditions are right, still sail past the stopping point, be that a signal or station.
I suppose that is the downside of disc brakes and very light trains !

If, and I stress IF, it was caused by Leaf Fall, what is in place to try taking it into account? Do drivers drive differently regarding technique in Autumn?

In known areas, they drive to the conditions prevailing, this however does not always stop a slide, after every such event a form is completed by Driver / Signaller, altered working in place until track examined and if needed treated.
I recall last year after a report of poor railhead conditions, an RHTT was taken of its booked run to Cromer, and did 3 return trips Trowse-Wymondham.

 

[Surreytraveller]

If, and I stress IF, it was caused by Leaf Fall, what is in place to try taking it into account? Do drivers drive differently regarding technique in Autumn?

Brake earlier, reduce speed.
Regardless of whether its the driver is blameless or not, its still a SPAD, as the train should have stopped at the signal

 

[WestRiding]

Brake earlier, reduce speed.
Regardless of whether its the driver is blameless or not, its still a SPAD, as the train should have stopped at the signal

Thanks, relieved the signalling equipment was working correctly.

 

[hexagon789]

So am I right in saying this technically was a SPAD? Red light comes on, SWR driver (or TPWS) brakes, braking system fails due to low adhesion, SWR ploughs into GWR. Is that how it went down? Or would 'SPAR' be more appropriate?

Not so much braking system fails, more the low adhesion results in insufficient braking distance for the available braking rate.

I understand SPARs are for SPADs that aren't due to driver error, that is to say outwith their control. Previously they were lower category SPADs.

 

[WestRiding]

Not so much braking system fails, more the low adhesion results in insufficient braking distance for the available braking rate.

I understand SPARs are for SPADs that aren't due to driver error, that is to say outwith their control. Previously they were lower category SPADs.

I believe the RED aspect had been happily showing. It did not revert from a proceed to danger in front of the train. SPAD.