Transportation Safety 3

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Message 2087210 - Posted: 1 Nov 2021, 8:45:43 UTC

Further news updates and photographs being posted:

Salisbury train crash: Investigation as several hurt

Both trains would have been travelling away from the camera, and entering the tunnel.The first train - that hit an obstruction in or around the tunnel - approached from the left: the second approached from the right, seven or eight minutes later. Google map of the junction.
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Message 2087219 - Posted: 1 Nov 2021, 11:10:56 UTC - in response to Message 2087210.  

Both trains would have been travelling away from the camera, and entering the tunnel.The first train - that hit an obstruction in or around the tunnel - approached from the left: the second approached from the right, seven or eight minutes later. Google map of the junction.
So with the second train following after the first- i guess it comes down to what does "knocking out signalling in the area." actually mean???
To me it implies that all signalling in the area was affected. ie both tracks, in which case the second train should have stopped due to the lack of a green signal.
But if it was was a case of the signalling being taken out only for the left track, then the signals for the right track could well have still been green- so no need for the second train to stop.

Something for the investigation to determine, and to consider- if on a multi track section the signalling for a single track fails- should all signals on all tracks on that section revert to all Red, until an inspection confirms the other lines are safe to use? This could very well be a compelling argument for Yes (if it isn't already the case). And if it is already the case, what was the status of the still functioning signals for the other track and how did the second train come to hit the first?
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Message 2087345 - Posted: 2 Nov 2021, 21:38:43 UTC - in response to Message 2087219.  

Update.
1st train was protected by a red signal. However, 2nd train went past it because of wheel slip. Accident report to be released later this week.
Wheel slip caused SPaD
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Message 2087351 - Posted: 2 Nov 2021, 22:26:46 UTC - in response to Message 2087345.  
Last modified: 2 Nov 2021, 22:27:03 UTC

That will be the preliminary report, which should give an outline of the findings so far, and say what form the final report will take. There will be some additional, significant things to consider such as why the first train derailed, the actions of the two drivers, signallers etc.
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Message 2087357 - Posted: 2 Nov 2021, 22:46:48 UTC - in response to Message 2087351.  
Last modified: 2 Nov 2021, 22:48:44 UTC

That will be the preliminary report, which should give an outline of the findings so far, and say what form the final report will take. There will be some additional, significant things to consider such as why the first train derailed, the actions of the two drivers, signallers etc.
And possible speed restrictions depending on the weather; signal position- ie signals need to be further back from the point they are protecting to allow for increased stopping distance in adverse conditions if the present speed limit remains unchanged.

One query-
The trains involved- they're electric/diesel electric? Do the regenerative braking systems employ ABS at all? I know that ABS actually increases stopping distance significantly on loose gravel. I'm wondering if that might be the case here with the track conditions at the time of the accident?


Thanks for the updates everyone.
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Message 2087358 - Posted: 2 Nov 2021, 23:17:01 UTC

I thouht Halloween was 2 days ago...
A man wearing a Fred Flintstone costume was hit and killed while harassing traffic in Texas early in the morning on Tuesday, Nov. 2, police told media outlets.

Police received calls from several motorists concerned about a costumed man in the middle of O’Connor Road, in northeast San Antonio, swinging at passing cars with what appeared to be a “spear,”
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Message 2087368 - Posted: 3 Nov 2021, 5:22:31 UTC - in response to Message 2087358.  

I thouht Halloween was 2 days ago...
A man wearing a Fred Flintstone costume was hit and killed while harassing traffic in Texas early in the morning on Tuesday, Nov. 2, police told media outlets.

Police received calls from several motorists concerned about a costumed man in the middle of O’Connor Road, in northeast San Antonio, swinging at passing cars with what appeared to be a “spear,”

Fittingly, today is Dia de los Muertos, or Day of the Dead.
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Message 2087376 - Posted: 3 Nov 2021, 8:15:08 UTC - in response to Message 2087357.  

The trains involved- they're electric/diesel electric? Do the regenerative braking systems employ ABS at all? I know that ABS actually increases stopping distance significantly on loose gravel. I'm wondering if that might be the case here with the track conditions at the time of the accident?


The units concerned were both diesel hydraulic(ish). They are fitted with a system called "WSSP", which is meant to reduced wheelslip and spin when they encounter poor adhesion conditions during braking and acceleration. Over the years I was involved in "tuning" a number of these systems and they generally resulted in a reduction in stopping distances and less wheelspin during acceleration. BUT, for some perverse reason a number of classes of units had the "slip" part of the system disabled in emergency braking....
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Message 2087378 - Posted: 3 Nov 2021, 9:17:13 UTC

On a somewhat lighter note:
https://www.bbc.co.uk/news/av/world-latin-america-59136233
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Message 2087431 - Posted: 4 Nov 2021, 8:56:15 UTC - in response to Message 2087357.  

The first very brief official report
https://www.gov.uk/government/news/collision-between-passenger-trains-at-salisbury-tunnel-junction?utm_medium=email&utm_campaign=govuk-notifications&utm_source=0656e38e-e6d2-4575-80cb-87c151a0d095&utm_content=daily

This document outlines what happened and what the RAIB will be looking at during their investigation.
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Message 2087446 - Posted: 4 Nov 2021, 16:08:47 UTC - in response to Message 2087431.  
Last modified: 4 Nov 2021, 16:11:31 UTC

Wow! The poor sod was braking but skidded through TWO signals!!

... And that junction has the potential for a head-on collision.


Looks like a redesign is needed somewhere for that one... (And elsewhere?)

... Including looking at the timetabling if excessive speed is being required...


Stay safe folks...
Martin
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Message 2087448 - Posted: 4 Nov 2021, 16:38:17 UTC - in response to Message 2087446.  

Just about every low/medium speed junction in the UK (and indeed in the rest of the world) has at least one potential conflicting move. Redesigning such junctions would be a grade one headache, and the doing the actual work would be at the very least "F" on the expensive job scale.
Speed limits are (in the UK) set by a pretty stringent set of rules, determined by signal spacing, gradients and sight lines. Timetables are developed using these speeds, not the other way round. There have been some quite dramatic arguments over the years between the signalling community and the operators when the operator wants to increase the speed at a point on the network without the required signalling and other infrastructure changes.
There are a few other things that need to be looked at, such as how well the second unit was maintained, and to what standard was it being maintained. The units involved have a very limited amount of sand available and there are some "rather strange" rules around where, when and how sand is applied (both in terms of track layout and vehicle layout), did any of these contribute to the unit sliding in the way it did. (I suspect that one or two people in the rail industry may have their pet hobby horses challenged.)
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Message 2087454 - Posted: 4 Nov 2021, 19:32:38 UTC

Driver who led CHP on chase through LA, Ventura Counties in stolen big rig surrenders in Santa Ana
After more than 10 hours that included a dramatic chase and a standoff that halted traffic, the driver of a stolen big rig finally surrendered to authorities Thursday morning.

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Message 2087467 - Posted: 4 Nov 2021, 23:16:12 UTC - in response to Message 2087431.  
Last modified: 4 Nov 2021, 23:22:16 UTC

The first very brief official report
https://www.gov.uk/government/news/collision-between-passenger-trains-at-salisbury-tunnel-junction?utm_medium=email&utm_campaign=govuk-notifications&utm_source=0656e38e-e6d2-4575-80cb-87c151a0d095&utm_content=daily

This document outlines what happened and what the RAIB will be looking at during their investigation.
Thanks for that.

From that initial report, the second train driver applied brakes at the initial caution signal. 12 seconds later he applied emergency braking. While already under the driver initiated emergency braking another emergency brake demand was made by the train protection and warning system (TPWS) ( i suspect this occurred once the train went through the red signal).
The interesting point- the wheels were sliding when the driver applied service brakes at the caution signal. With little to no adhesion with just normal braking, there was no chance of the second train stopping in time, even if emergency braking was started sooner.
From the looks of that initial report, the signals were working for the second train, the driver did everything by the book, but he had no chance of stopping due to condition of the track.


My reading of the report is that the first train didn't derail- it was actually using the points to enter the main line when the second train ran in to it, and derailed both. So the first train was probably running late (unlikely the second was early) and if the second train had been able to stop normally the only issue would have been passengers arriving at their stops later than the timetable indicated.
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Message 2087489 - Posted: 5 Nov 2021, 9:34:44 UTC - in response to Message 2087467.  
Last modified: 5 Nov 2021, 9:35:10 UTC

Witnesses on the first train, not referred to in this initial report, said that the first train lurched to a stand a couple of minutes before the second one arrived on the scene. As you say, the next report (interim) and the final one will be a much bigger read.
In my experience of reading these reports in sequence the initial report is very thin of witness evidence, much of which isn't normally available to the RAIB in the early days. Subsequent iterations go more into witness evidence, CCTV signalling records and so on, all of which has to be correlated to get an accurate timeline of events. In this case I would expect .statements to be taken from the passengers on both trains (only a couple of dozen), and the train crews & signallers (who will have a "union man" with them, who is normally a very experienced driver or signaller as appropriate).
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Message 2088156 - Posted: 15 Nov 2021, 17:58:32 UTC

Been watching many military documentaries on Youtube over the past few years as well as some music videos of songs from the past.
Was surprised to see a rash of programs in the recommended list & watched many of them.
Mainly Police Interceptors/Motorway Cops.
The excuses heard when caught are hilarious at times but they all have a common denominator - paltry sentences.
Sad
Until the punishment hits where it really hurts, it will not stop.
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Message 2088208 - Posted: 16 Nov 2021, 8:40:40 UTC

Some people have more money than commonsense.

Man cut free after crashing luxury Ferrari in St Peters, Sydney.

He'll be short of a few dollars now.

Cheers.
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Message 2088220 - Posted: 16 Nov 2021, 14:12:07 UTC

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Message 2088225 - Posted: 16 Nov 2021, 14:43:10 UTC - in response to Message 2088220.  

...and installed another radiator

Two jobs at once, all done in a few seconds, what a smashing fellow he is ;-)
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Message 2088230 - Posted: 16 Nov 2021, 16:01:08 UTC - in response to Message 2088225.  

ROFLMAO.
Nice extraction.
Hope all parties are insured...
...otherwise...
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