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LNER empty trains collided, service disruptions expected


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Just read the last two pages to get up to speed.  I picked up the new edition of Rail yesterday and in their report about the incident it mentioned that cab ergonomics are one of the factors that are being investigated.   That would fit in with something I was told last Friday.   I will await the outcome of the report with interest.

 

Jamie

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2 hours ago, Mallard60022 said:

So, after all this surmising, has anyone with some sort of higher knowledge of Physics and engineering, had a go at calculating what they think might happen at 140mph with one of these things if it hits another fairly solid object either whilst still on the track (as at Heck), or when in flight having departed the track in some way? Me being ignorant is bloody worried at the thought of what I think will happen. 

P

Hi Mallard,

 

My guess would be a high speed collision would split the carriages open along the weld lines of the aluminium extrusions just like the DVT at Great heck and the ICE that crashed into the bridge in Germany some years back.

 

Gibbo.

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1 minute ago, Gibbo675 said:

Hi Mallard,

 

My guess would be a high speed collision would split the carriages open along the weld lines of the aluminium extrusions just like the DVT at Great heck and the ICE that crashed into the bridge in Germany some years back.

 

Gibbo.

 

I think it would certainly stack the coaches up against the bridge the same as the ICE did

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2 hours ago, Mallard60022 said:

So, after all this surmising, has anyone with some sort of higher knowledge of Physics and engineering, had a go at calculating what they think might happen at 140mph with one of these things if it hits another fairly solid object either whilst still on the track (as at Heck), or when in flight having departed the track in some way? Me being ignorant is bloody worried at the thought of what I think will happen. 

P

 

3 minutes ago, Gibbo675 said:

My guess

 

Must be educated guess work....:rolleyes:

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6 minutes ago, chris p bacon said:

 

 

Must be educated guess work....:rolleyes:

Hi Dave,

 

As a former weld engineer at Watson Steels that holds nine weld codes amongst various other engineering qualifications, I would say its a fairly good guess.

 

Gibbo.

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15 minutes ago, Gibbo675 said:

Hi Mallard,

 

My guess would be a high speed collision would split the carriages open along the weld lines of the aluminium extrusions just like the DVT at Great heck and the ICE that crashed into the bridge in Germany some years back.

 

Gibbo.

 

And the Thames Turbo at Ladbroke Grove!

 

Its rather telling that when the emergency services turned up they thought the DMU was only a 2 car unit such was the destruction of the leading vehicle - which had split apart and disintegrated in the manor you describe.

 

The thing is while Aluminium might be a wonderful material - light, does not corrode, etc it is fundamentally a very weak metal. To make it strong enough to use as a bodyshell all sorts of geometrical tricks need to be used to gain structural strength. Thus while aluminium bodysehells will perform well when subjected to the specific forces the designer actually anticipated in the design - the same does not hold true when the forces are applied in a manor not foreseen by the designer.

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5 hours ago, Oldddudders said:

So buckeyes have always helped practical safety in overtaking accidents. Given that the 8xx vehicles are 26 metres in length, nearly one-third longer than the typical 20 metre length of most Big 4 and earlier BR coaches, we can understand why an alternative connecting mechanism within set was needed having regard to end-throw etc, but prima facie there may be a downside. All this must surely come out in the wash currently in the investigation machine. 

 

The use of fixed bar couplings probably has more to do with saving costs and weight, as they operate in fixed sets with no need to uncouple vehicles. I believe some other modern fixed formation trains, of shorter vehicles, also use similar systems.

Also operational convenience, as they're classed as permanently coupled it exempts them from the rule prohibiting running with the brake isolated on the leading or trailing vehicle

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2 hours ago, Mallard60022 said:

So, after all this surmising, has anyone with some sort of higher knowledge of Physics and engineering, had a go at calculating what they think might happen at 140mph with one of these things if it hits another fairly solid object either whilst still on the track (as at Heck), or when in flight having departed the track in some way? Me being ignorant is bloody worried at the thought of what I think will happen. 

P

Calculating what will happen in a real high speed impact or derailment is well nigh impossible, bar knowing that with that much kinetic energy to be dissipated it is quite likely to be very destructive, more so if any object that is struck is effectively immovable. That's physics, and the only real way to mitigate against the consequences is to do everything practicable to avoid such a situation occurring. It's the same as with aeroplanes, which are not something that anyone would describe as crash resistant. Accidents with aircraft tend to have low survivability, but air travel is safer than train travel simply because such events do not happen very often.

 

it should not be forgotten, either, that a significant cause of injury in train accidents is the passengers themselves, along with their luggage. The train may stop, but they don't, and it is generally reckoned that passengers would neither tolerate being strapped in nor having their luggage stowed in crash proof bins.

 

Jim 

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2 hours ago, jim.snowdon said:

it should not be forgotten, either, that a significant cause of injury in train accidents is the passengers themselves, along with their luggage. The train may stop, but they don't, and it is generally reckoned that passengers would neither tolerate being strapped in nor having their luggage stowed in crash proof bins.

 

Jim 

Hi Jim,

 

I see that you've seen the size of some of the cases that some think appropriate to store in overhead racks then, some of them would be dangerous just falling off never mind on become missiles in an accident.

 

Another possible issue with the 80x's. With there lack of luggage room and not "wasting space" having a van area  that they can squeeze even more seats in, even medium sized cases are meant to go on the overhead racks.

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5 hours ago, Ken.W said:

"wasting space" having a van area  

 

The only service we ran where the HST's luggage areas in the power cars were  fully used were the summer Saturdays trains to the SW and even then we had to practically beg people to put their bags down there. People want to have their bag as close as possible to them, I can assure you that the present travelling public will not use a "van area" even if it's provided unless they are forced to!! And that's before you factor in longer dwell times at stations due to people having to walk the length of the train to collect their bags... In the days when there were lots of staff and we were not as rushed they work. Not now.

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7 hours ago, phil-b259 said:

 

And the Thames Turbo at Ladbroke Grove!

 

Its rather telling that when the emergency services turned up they thought the DMU was only a 2 car unit such was the destruction of the leading vehicle - which had split apart and disintegrated in the manor you describe.

 

The thing is while Aluminium might be a wonderful material - light, does not corrode, etc it is fundamentally a very weak metal. To make it strong enough to use as a bodyshell all sorts of geometrical tricks need to be used to gain structural strength. Thus while aluminium bodysehells will perform well when subjected to the specific forces the designer actually anticipated in the design - the same does not hold true when the forces are applied in a manor not foreseen by the designer.

Hi Phil,

 

I was unaware of the Thames Turbo situation at Ladbroke Grove, also you are quite correct in that aluminium is an excellent material. Unfortunately when high strength aluminium alloys are welded they loose their mechanical properties without post weld heat treatment, in certain circumstances the alloy may revert back to its fully annealed state within the heat affected zones. The trouble with longitudinal welds in a body shell is that due to the size, shapes and mass of material involved post weld heat treatment is difficult not just because of physical parameters imposed by the body shell but also that should the heat treatment be miss applied then the fabrication could warp out of shape when released from the jig. In a crash situation, should a body shell be impacted in just the wrong spot, then a weld that runs the full length of the body shell may fail, added to which aluminium is far more subject to brittle failure which exacerbates the problem further.

 

To my mind steel is a far more superior material for building railway vehicles for in crash situations it performs much better than aluminium. It is safe to say that even when looking at increased section for a given load that steel will be better for its failure mode is much more likely to be elastic plastic failure in nature rather than the brittle failure generally displayed by aluminium generally.  (As an analogy for those unfamiliar, broken glass displays brittle failure, warm toffee displays elastic plastic failure.)

 

As Jim Snowdon has noted above aeroplanes are not particularly crash resistant, despite mostly being made from aluminium they are in the main either riveted, bolted or glued together. Welding is not very often employed so that the materials retain their maximum strengths for they are not subject to the heat input from a welding process so that thin section may be used in their construction. Interestingly the APT-E was riveted in construction, its body shell was built in an aircraft factory.

 

Gibbo.

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Very few vehicles stand up well to the severity of opposing direction collisions, never mind high speed collisions with unyielding objects such as bridges. The challenge to the designer is achieving an affordable compromise between weight, strength and risk. Unlike roads, for example, railways represent a controlled system where many other precautions are taken by design to mitigate against the possibility of trains colliding with each other.

 

Jim

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The Pendolino is a modern(ish) aluminium train - did well when derailed at 95mph, brought the overhead down (with some masts) and went down an embankment. True it didn't run into anything other than some OHLE masts.

 

VirginPendolinoDerailment.jpg

 

traincumbMOS2402_228x379.jpg?w968

 

stream_img.jpg

 

And NO I do not wish to see an 800 in a similar situation, but more structural tests would certainly put those in doubt at a little more ease. A LOT of money is being invested in these, and they, like it or lump it will soon be THE main high speed train for most in the future for many years.

 

Brit15

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10 hours ago, phil-b259 said:

Its rather telling that when the emergency services turned up they thought the DMU was only a 2 car unit such was the destruction of the leading vehicle - which had split apart and disintegrated in the manor you describe.

 

The thing is while Aluminium might be a wonderful material - light, does not corrode, etc it is fundamentally a very weak metal. To make it strong enough to use as a bodyshell all sorts of geometrical tricks need to be used to gain structural strength. Thus while aluminium bodysehells will perform well when subjected to the specific forces the designer actually anticipated in the design - the same does not hold true when the forces are applied in a manor not foreseen by the designer.

 

The head on collision near Bari in Italy in 2016 was between an Alsthom Coradia and a Stadler Flirt, both pretty much brand new, but of different construction methods. The Flirt was constructed from aluminium and came off much worse than the steel built Coradia.

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15 hours ago, Titan said:

One thing that should be remembered is that at this point in time the threshold value of what constitutes a write off will be much lower than what it would be in say 5 years time when the 800's are no longer in production. Any damage now which would be more difficult to fix than just simply adding a couple of extra bodyshells to the production run and swapping parts over will be a write off.  When the only option is fix it or do without then the threshold for economic repair will be a lot higher.  66734 was a brand new loco, and was scarcely damaged in it's derailment, but it was deemed more economical to order a new one and dismantle it on site rather than recover it. Incidentally about 85% of components were recovered for further use.

 

Similarly with the class 47's. 512 built, but never more than 510 extant at any one time.  One can't help thinking that a total of 510 were desired, plus two extra to cover those written off in accidents, which might otherwise have been repaired had 47's not still been rolling off the production line.

The other thing which has changed is that the railway, in its various parts, now carries commercial insurance and we don't know what the excess happens to be If any).   Plus we are very much in a situation where the insurance company will effectively write-off something because that is the cheapest way for it to deal with the claim, especially when the production line is still working and parts can be recovered to offset cost in the new build.

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3 hours ago, Gibbo675 said:

Hi Phil,

 

I was unaware of the Thames Turbo situation at Ladbroke Grove, also you are quite correct in that aluminium is an excellent material. Unfortunately when high strength aluminium alloys are welded they loose their mechanical properties without post weld heat treatment, in certain circumstances the alloy may revert back to its fully annealed state within the heat affected zones. The trouble with longitudinal welds in a body shell is that due to the size, shapes and mass of material involved post weld heat treatment is difficult not just because of physical parameters imposed by the body shell but also that should the heat treatment be miss applied then the fabrication could warp out of shape when released from the jig. In a crash situation, should a body shell be impacted in just the wrong spot, then a weld that runs the full length of the body shell may fail, added to which aluminium is far more subject to brittle failure which exacerbates the problem further.

 

To my mind steel is a far more superior material for building railway vehicles for in crash situations it performs much better than aluminium. It is safe to say that even when looking at increased section for a given load that steel will be better for its failure mode is much more likely to be elastic plastic failure in nature rather than the brittle failure generally displayed by aluminium generally.  (As an analogy for those unfamiliar, broken glass displays brittle failure, warm toffee displays elastic plastic failure.)

 

As Jim Snowdon has noted above aeroplanes are not particularly crash resistant, despite mostly being made from aluminium they are in the main either riveted, bolted or glued together. Welding is not very often employed so that the materials retain their maximum strengths for they are not subject to the heat input from a welding process so that thin section may be used in their construction. Interestingly the APT-E was riveted in construction, its body shell was built in an aircraft factory.

 

Gibbo.

What's your opinion on the friction stir welding used by Hitachi?

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19 hours ago, APOLLO said:

What I find disturbing is that it was not just the front car, it seems several cars affected, the impact shock went through the entire train,. Buffers, or at least some shock absorbing coupling system would have helped to absorb the impact.

 

They certainly don't build them like these anymore !!

 

Then there are these crazy ************* - This train "seems" OK

 

The ultimate hard coupling - watch the second & third loco's frame flex - no problem - couple up & good to go - built like a brick sh1thouse

 

800's - tinfoil trains - melt em down quick for Christmas turkey roasting trays !!

 

Brit15

 

All that said I'd still rather take my chances in an accident in an 800 series train than any of the Southerns slam door stock......

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6 minutes ago, admiles said:

 

All that said I'd still rather take my chances in an accident in an 800 series train than any of the Southerns slam door stock......

 

I wouldn't be so sure that 800 seemed to come off worse than the EPB which hit the stops at Cannon street 

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37 minutes ago, russ p said:

 

I wouldn't be so sure that 800 seemed to come off worse than the EPB which hit the stops at Cannon street 

I think it all depends on what we couldn't see in any of the pictures - the bit where the passengers would be sitting.   What we don't know (I presume) is the extent to which IET passenger vehicle ends are designed to deform in a collision in order to protect the central part of the vehicle structure .

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43 minutes ago, Talltim said:

What's your opinion on the friction stir welding used by Hitachi?

Hi Tim,

 

I know of it as a process but I have not had any experience of it other than reading books and watching videos at college and university. Most of my work place experience has been in either boiler or constructional grades of steel, copper for fire box work and aluminium for building motorbikes in my shed using SAW, MMA, GMAW and TIG/TAG processes.

 

In general terms a correctly performed weld ought to be stronger than the original parent metal, the weakest part of any welded joint are in the heat affected zones adjacent to the weld itself. I do know that the stir welding technique reduces heat input considerably compared with more traditional electric arc or plasma weld processes without need for any filler material however, the longitudinal joints will still form a stress raise running the whole length of the body. That stir welding does not require any filler materiel allows for better control of the material within the weld as nothing is added to the weld area.

 

Such long welded joints do seem to be an inherent weakness in any such design in the way the seam of a pea pod tears along its length, this will be due to the change in the grain structure of the weld area and also the deposition of the alloying agents within that grain structure. I would have to do a lot of reading to find out exactly how the stir welding process affects the particular aluminium alloy used by Hitachi and so anything more than a general observational comment would not be of any use in this context as it would be no more than guess work.

 

The engineers that designed and built the rains are not stupid, but I do see generally, and not just in the railway industry that engineered projects such as trains are not lead by engineers but driven by our friends the bean counters. It seems to me that cost per head carried, per ton, per unit cost of energy, per unit cost of life cycle over performance is much more important to bean counters than trains that don't fall to bits in a crash. The Mk3 body shell was designed to be as safe as reasonably practicable and while not overly heavy it is a lot heavier than more modern designs, all engineering is a compromise in some way, shape, form or other, perhaps the Mk3 was at the point upon the graph where the lines crossed ? That the HST had ding on the pointy end and the 800 is a knacker that fell of the track due to a 9 mph collision to me speaks volumes about design philosophies that have an over emphasis on financial constraints.

 

Gibbo.

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6 hours ago, Hobby said:

 

The only service we ran where the HST's luggage areas in the power cars were  fully used were the summer Saturdays trains to the SW and even then we had to practically beg people to put their bags down there. People want to have their bag as close as possible to them, I can assure you that the present travelling public will not use a "van area" even if it's provided unless they are forced to!! And that's before you factor in longer dwell times at stations due to people having to walk the length of the train to collect their bags... In the days when there were lots of staff and we were not as rushed they work. Not now.

 

Really?? I can assure you that they DO work as used on East Coast services!

 

At busy times like holiday periods, bank holidays, etc, a luggage check in service is operated at Kings X and Edinburgh.

Large luggage for the destination station are taken and checked in, given a tag label, as passengers enter the platform, and stowed in the van.

The luggage is in a locked van during the journey, not in an open rack at the coach ends next to the exit door (handily placed for the luggage thieves) - with large items you don't 'have them with you' at your seat even if they are in the coach with you, unless of course you're one of those who block the isle with them.

At destination the vans unloaded, plenty of time there, and passengers reclaim their luggage with their tags.

When this service is operating, the van ends up being full, even on a Mk4 with the DVT, you really want this amount of extra luggage in the coaches with you?

Luggage space in the coaches is freed so there's actually some for passengers at intermediate stations, so time's actually saved as there's fewer passengers looking around when boarding with nowhere to stow their luggage.

For through trains north of Edinburgh, the service is also provided for the destination / originating station, and they generally have around a 10 stop in Edinburgh which provides sufficient time for the Edinburgh luggage to be handled.

You "can assure me the present traveling public won't use a van.. unless they're forced to"? Well let me assure you that if you look you'll see them actually queuing up to use this service!!

 

The van area's also well used at other times. The bike racks are often too, and a Mk4 DVT can take 6. There's often also other large items carried unsuitable to go in the coach.

 

Presumably though you'd prefer to be in the alternative, on an 80x with luggage racks designed to take cases so large as to become potential lethal missiles in an incident at speed even as low happened here.

Or have isles so full of luggage the catering trolley can't get through, or even, as has happened on 800s as they're so short on luggage space, the gangway between vehicles actually blocked with luggage, so you can't even go to the trolley / buffet to get your own? But oh, of coarse that's something else we're told the 'modern passenger' doesn't want to do either, so I presume you'll have no complaints when the catering's withdrawn as it isn't / can't be used?

 

Remember, these things are supposed to be long-distance 'Inter-city' trains which need to regularly cater for passengers with large amounts of luggage, they're not operating commuter 'pack as many in as you can' services!

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11 minutes ago, Ken.W said:


Remember, these things are supposed to be long-distance 'Inter-city' trains which need to regularly cater for passengers with large amounts of luggage, they're not operating commuter 'pack as many in as you can' services!

 

The problem is that is precisely what they have become!

 

Why do you think First went and converted the HSTs they used at the time on Bristol runs to a 'high density' layout without a buffet car a decade or so ago?

 

Now admittedly London to Edinburgh is not quite the same as London to Bristol and it may well be that what is really needed is two variants of 800s (just as although the Bristol runs used 'high density' HST sets, workings to Devon / Cornwall retained more seats at tables plus the buffet car), however if the dfT / TOCs want to go down the 'uniform fleet' setup then inevitably its long distance travellers that will be forced to lose.

 

 

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They might be supposed to be long distance ic trains but most of the passengers aren't. These days we have a bigger percentage of short/medium distance commuters who more often than not outnumber the long distance crowd. with increased in the number of trains and stops it has encouraged the long distance commuter who are often the majority. Hence seats take priority over luggage on modern trains.

 

Yes I do have trouble in getting them to use the spaces we have and an awful lot of people don't like their bags to be out if sight. It may be different on London centric ic trains but I can assure you my experience is as I have stated. I don't make things up for the sake of it. i only wish what you say is true but my experience at work is that it isn't. 

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2 hours ago, russ p said:

You certainly wouldn't want to stand in a gangway 

 

Though in a situation such as you quoted at Cannon Street, entering a terminal platform, there would be some who'd be standing in that area

Other than those that've read this thread

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