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Krystal n chips
18th Apr 2012, 04:32
Must have been "interesting" for all concerned.... let alone the driver.

However, given the number of rail professionals on here, a query please about the sandbox....which seems to be ( allegedly ) a causal factor.

I am aware of the use of sand to assist traction but how does ot work with the braking system as I was under the impression the brakes were vacuum operated.?

Also interesting to see that, not only with this incident, but also others recently, the regulatory authority imposing themselves on the TOC's / Network Rail....at last...

.....although the latter still have "some way to go" as they decided that a refurbished station at Cosford was ready for the public to use....despite the ahem, minor detail that it was lacking information signs / shelters / seats....and still not completed....:ugh:


BBC News - Southeastern faces court after train overshot station (http://www.bbc.co.uk/news/uk-england-sussex-17744655)

From the local(ish) news....

BBC News - Cosford railway station reopening delayed again (http://www.bbc.co.uk/news/uk-england-shropshire-17738111)

sitigeltfel
18th Apr 2012, 04:55
Was once on a TGV down here from Paris that failed to stop at Valence, despite being scheduled to do so. The disgruntled pax all had to get off at Avignon and wait for a chartered bus to take them back up North as it was late, and there were no more North bound trains.
Irate French people are a sight to behold!

McGoonagall
18th Apr 2012, 06:29
I am aware of the use of sand to assist traction but how does ot work with the braking system as I was under the impression the brakes were vacuum operated.? Firstly, there are very few if any vacuum braked trains on the network today, any that are will be vintage charters and the suchlike. All are air braked.

A train will slide when braking if either the railhead and/or the wheel tread is contaminated. During leaf fall, compressed leaves turn into a viscous gel which allows very little if any friction on the wheel/rail contact. Applying sand while braking will assist in maintaining contact with the rail and allow speed to decay while braking. Todays modern trains are in the main disc braked (along with rheostatic and regenerative braking by reversing traction motors) and this in turn in absence of a brake block making contact with the wheel surface allows contamination to build up more easily.

Sanding is nearly always automatic on todays trains when slide activity is detected and the majority of younger drivers are taught to expect this. It is not their fault that they have had no experience of controlling slip/slide by manual sanding/differential braking. Very much like the aviation industry we are becoming forced to adhere to company driving policies that owe more to them covering their own backs rather than common sense and allowing drivers to use their experience to control trains in all conditions.

OFSO
18th Apr 2012, 10:30
Given the age of the people travelling on South Eastern, it wouldn't be surprising if at least half of them didn't know where they were anyway, no matter where they disembarked.

(That's just a joke, my parents lived in Eastbourne and I liked it very much there. And no, they didn't have a Honda. That's another joke.)

I was also unaware that travelling on the local train from French/Spanish border Port Bou to Figueras, you have to go and tell the driver that you want to get off at Villajuiga or he won't stop. Hence it was that I was able to see my car in the car park there as we sped past at 60 kph.

Regarding the TGV not stopping at Valence: I notice a lot of rescheduling since some trains come on to Spain, in particularly they don't all stop at Sitges or Agde or Bezier now, which must cause confusion, not least for the drivers or pilots on the TGV's. It certainly confuses ME and one of these days I just know that will be waiting to pick up Mrs OFSO in Figueras when she's got off in Perpignan, or v.v.

Evening Star
18th Apr 2012, 10:46
As often said here, read the official report: RAIB 18/2011 (http://www.raib.gov.uk/cms_resources.cfm?file=/111117_R182011_Stonegate.pdf). Low railhead adhesion conditions (leaves) and a maintenance issue with procedures for replenishment of sand.

Slight thread drift, in that it is obviously going to take a major accident before leaves on the line stops being a joke :ugh:. Sad reflection on life.

Tankertrashnav
18th Apr 2012, 11:05
I wonder if anyone saw a programme a few weeks back when a Virgin Pendelino driver went over to Peru (I think) to experience driving really heavy freight trains on a very steeply graded mountain route, . On the very long down grades, knowledge of how and when to work the brakes was crucial, runaway trains were not unknown, and could end up in catastrophic derailments. I noticed that at times sand was running almost continuously from the hoppers to help maintain braking.

To me it was a bit like a 757 pilot being asked to do his normal route in a DC2, and it was very chastening for the Virgin man who returned home to his comfy Pendelino cab with huge respect for the freight drivers.

stumpey
18th Apr 2012, 20:20
I sure that programme. Bit of good old fashioned World wide inter- Trade Union exchange. He came back realising just how lucky we are in the west. I understand his union now have some sort of monthly collection to help those fellow workers abroad.
(Perhaps with all the whining and wingeing on the Military forum we should try a bit of exchanging of some of our current "Extenders of Political will". We knew how to moan, but we kept it out of earshot of the SWO!)

G-CPTN
19th Apr 2012, 14:29
As a retired vehicle test engineer, I read the RAIB report with interest (and fascination).
I understand 'antilock', and, it seems that the system that prevents wheel-locking was detecting a low-grip situation and preventing the brakes from acting, despite the request from the driver for 'emergency' braking.
This, whilst understandable for a normal service system, seems strange that there is no 'crash-stop' provision.

Of course, sliding friction (with wheels locked - ie skidding) is generally less-efficient that when wheel-rotation under braking is maintained, but I can't help thinking that a bit of metal-to-metal might have removed the contamination that was causing the low grip.

I appreciate that there was no 'emergency' (the signals ahead were clear and the crossing-gates were closed automatically) and the driver was not at fault (the black box confirms that he applied the brakes at the appropriate distances and responded accordingly when he detected a lack of retardation) but, had there been an obstruction on the line there was, it seems, absolutely nothing that the driver could have done differently.

The RAIB report is worth reading (it contains all the relevant facts):-
http://www.raib.gov.uk/cms_resources.cfm?file=/111117_R182011_Stonegate.pdf

See figure 3 on page 12 and table 1 on page 22.

McGoonagall
19th Apr 2012, 14:40
The train was travelling at 50 mph and it overshot by two and a half miles? It doesn't take two and a half miles to stop a train travelling at 50 mph. The train failed to stop because the driver forgot to stop there. 'No sand in the boxes' was a red herring to cover the driver's mistake. An 'overshoot' is when a train is actually stopping and it travels past the platform. This was no overhsoot . . . You must be a troll. What an absolute load of nonsense. If the driver did have a fail to call then the OTMR (black box) would have proven this and the driver been suitably disciplined. The OTMR records every driver action from braking to blowing the horn, records speeds, power handle position.... everything. The company, if the driver had failed to call, would not have spent tens of thousands fitting modifications and now be facing prosecution. They would have hung him out to dry.

I will tell you how controllable a train in wheel lock and slide is. Imagine the friction co-efficient of wet ice on wet ice, that is close to what a contaminated wheel on contaminated track is like. You put the brake on and the wheels lock and slide, you release the brake and the forward inertia continues the slide you re-apply the brake and with sand the braking action will return slowly. I personally have had a 3/4 mile slide with a 1500 tonne freight train and that was with ample sand being applied.

The culprit here is the maintenance depot that failed to ensure clean dry sand was in the hoppers, the company has already admitted no procedures were in place for this to be checked and have introduced new procedures.

Please feel free to read the RAIB report on this http://www.raib.gov.uk/cms_resources.cfm?file=/111117_R182011_Stonegate.pdf and then come back with a suitable new conspiracy theory.

:ugh::ugh::ugh:

NB. Posted after G-CPTN's more measured reply.

G-CPTN
19th Apr 2012, 15:04
Imagine the friction co-efficient of wet ice on wet ice, that is close to what a contaminated wheel on contaminated track is like. You put the brake on and the wheels lock and slide, you release the brake and the forward inertia continues the slide.
I know exactly what that feels like - although my tests were done (with a fully-laden 44 tonne truck and trailer) on a level surface with adequate space to pirouette safely.

The track where the train incident occurred is downhill (though the train is restrained laterally by the wheel-flanges against the rail) so it must be alarming and concentrates the anal sphincter.

Figure 2 on page 8 of the RAIB report shows the geography of the location with the action-points of the driver superimposed (I can't reproduce it here visually, as it is Crown Copyright).

Mac the Knife
19th Apr 2012, 16:28
"The train arriving at Platforms 3, 4, 5, 6, 7 and 8 is coming in sideways"

Mac :ok:

Krystal n chips
19th Apr 2012, 17:06
Evening Star....my thanks for the incident report.....:ok:.....as always, media version vs factual version. A very interesting read therefore.

McG.....thanks for the operational aspects. :ok:....the confusion re vacuum / air brakes was down to one being half asleep..when one posted...however the clarifications regarding braking and driving techniques / conditions were also very much appreciated...always nice to hear from somebody who knows what he is talking about...in contrast to others that is.

I have but one question however.....how, on a train, do you get differential braking please....on an aircraft, it's simple....boot the brake on the side you wish to turn and round she goes....you can't really do this on a train...:)

McGoonagall
19th Apr 2012, 17:57
I should have explained that a bit better. On a freight train (or loco hauled carriage stock) you have two brakes a proportional brake which applies the brake to all the train and a straight brake that applies on the loco only. As the only sanders are on the loco brakes, at slow speeds it may be beneficial to allow the wheels on the wagons to rotate out of a slide while using the straight air brake on the loco and sanding furiously. I have only used this on an empty freight working where the weight of the wagons did not exceed the weight of the loco by more than three or four times and only for short periods.

ZOOKER
19th Apr 2012, 18:01
Mac,
A fellow fan of I.S.I.R.T.A. perchance? :ok:

M.Mouse
19th Apr 2012, 21:28
Like many people I am fascinated by railway engineering in all its respects. The knowledgeable posts and the reports above make very interesting reading.

I recall seeing a TV documentary about one of the massive freight trains in California that the engineer discovered during a long, long descent had not got full braking. Explanation here. (http://en.wikipedia.org/wiki/San_Bernardino_train_disaster)

You could tell from his telling of the story how terrifying it was as the train slowly but relentlessy continued to gather speed all the time him realising that it would end in derailment at the end of the descent. The derailment was horrendous and demolished houses as well as killing four people.

One can only wonder what that was like to be driving a train weighing nearly 9,000 tons and reaching an out of control speed of 110 mph before derailing on a 35 mph curve.

G-CPTN
19th Apr 2012, 21:44
The runaway train (http://www.youtube.com/embed/TFJ3KayeUTc)

Mac the Knife
19th Apr 2012, 23:12
Zooker

Guilty as charged

Mac :ok:

Krystal n chips
20th Apr 2012, 04:04
McG......thanks for the clarification....:ok:

By a quirk of fate, today I will be driving a Class 40 on the ELR with 6 carriages in tow....and it's going to rain....not surprisingly, in Bury. So one will listen very intently to what the man stood behind is saying....

McGoonagall
20th Apr 2012, 07:10
Class 40 eh? Bit like me, overweight and underpowered. Enjoy.

:)

Daysleeper
20th Apr 2012, 09:39
G-CPTN

Figure 2 on page 8 of the RAIB report shows the geography of the location with the action-points of the driver superimposed (I can't reproduce it here visually, as it is Crown Copyright).

There is no problem with reproducing RAIB reports so go right ahead.

From the report...

You may re-use this document/publication (not including departmental or agency logos) free of charge in any format or medium. You must re-use it accurately and not in a misleading context. The material must be acknowledged as Crown copyright and you must give the title of the source publication.

Alloa Akbar
20th Apr 2012, 10:47
As they say in Wales.. "There it was... Gone."

Sunnyjohn
20th Apr 2012, 14:44
McGoonagall

You must be a troll. What an absolute load of nonsense.

You are absolutely right and I apologise unreservedly for my crassness. I have now read the report and am a lot wiser. I have deleted my unfortunate post.

McGoonagall
20th Apr 2012, 14:51
SJ, apologies for an overreaction on my part.

McG