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LNER empty trains collided, service disruptions expected

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We’re the both moving in the same direction though ?

 

i’m kind of puzzled at the kind of puzzled comments about the crash and derailment...

 

Testing if something is crash worthy, is something you do in the design phase, and have signed off before you start manufacturing production examples.. or is that old fashioned thinking ?

 

Surely the behaviour observed, should therefore be the expected behaviour, even if it looks a bit unexpected to untrained eyes ?

 

I guess the other question is about minor prangs (this isn’t a major prang in the big scheme of things), should be the time to repair.. if 800109 is out for any length, has LNER got sufficient reserve cover, to handle the quantity of incidents that may occur during the timeframe it takes to repair a unit... as knocking one out and going short doesn’t seem to be an option ?

Edited by adb968008
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Re the Azuma, derailment,  if the Azuma was under power with the controller open and not closed and coasting at the impact , would the drive" pushing from behind"  by the motor bogies cause the  inter-coach  damage and derailment of the unit

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Is it possible that the following:

- the design and validation of the class 800 train, including the ergonomics of its cab, its crashworthiness performance and its resistance to derailment in collision scenarios

 

is partly just taking the first opportunity to examine a new product's crash performance? 

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17 minutes ago, Nova Scotian said:

Is it possible that the following:

- the design and validation of the class 800 train, including the ergonomics of its cab, its crashworthiness performance and its resistance to derailment in collision scenarios

 

is partly just taking the first opportunity to examine a new product's crash performance? 

I would hope that those developing trains these days don't wait for a crash to ascertain crashworthiness.

 

Just likes cars I expect early test bodyshells to have been submitted to various types of force in order to demonstrate strength and integrity within design parameters.

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Just a thought - is the inter-car coupling 'sprung' at all or is it literally a rigid coupling? Might explain how the force of the collision has 'shocked' its way down the train.

Mk3 stock (inc HST) have the gangway providing a sprung buffing force and IIRC the buckeyes are mounted to a draft box with rubber(?) damping.

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7 minutes ago, keefer said:

Just a thought - is the inter-car coupling 'sprung' at all or is it literally a rigid coupling? Might explain how the force of the collision has 'shocked' its way down the train.

Mk3 stock (inc HST) have the gangway providing a sprung buffing force and IIRC the buckeyes are mounted to a draft box with rubber(?) damping.

I believe the issue of the vehicle inter-coupling, and its differences from the buckeye norm, was aired on page one of this thread. 

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Apologies Ian for not phrasing it very well (and its on p.3 as it was me that asked!)

I realise the middle bit joining the coaches together is rigid, I was just wondering how they're mounted to the vehicles and what kind of springing/damping is provided - or if it's all set to be very stiff due to the high-speed nature of the units.

I've tried to look at Dellner's website, but it doesn't load properly and seems to want to turn my PC into a hovercraft

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Do any of the guys 'in the know' have any thoughts regarding the possible withdrawal of the Azuma fleet pending the results of an enquiry? Would this  even have been considered? Just asking out of interest. I was a Leeds Driver for 31 years prior to retirement, and must have gone that way on to Neville Hill thousands of times, and indeed, moved up towards the dolly behind other moving trains, albeit slowly as the rails were often quite slippy there due to idling trains. Interestingly, it's also been the site of other derailments when stock has run away, in the opposite direction, off the depot and collided with the buffer stops on the adjacent headshunt. Cheers

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11 minutes ago, pippindoo said:

Do any of the guys 'in the know' have any thoughts regarding the possible withdrawal of the Azuma fleet pending the results of an enquiry? Would this  even have been considered? Just asking out of interest. I was a Leeds Driver for 31 years prior to retirement, and must have gone that way on to Neville Hill thousands of times, and indeed, moved up towards the dolly behind other moving trains, albeit slowly as the rails were often quite slippy there due to idling trains. Interestingly, it's also been the site of other derailments when stock has run away, in the opposite direction, off the depot and collided with the buffer stops on the adjacent headshunt. Cheers

Unless there was an obvious immediate danger to passengers then withdrawal of the fleets is not going to happen - how would the GWML run it's services, the HSTs are gone.

 

Similarly on the ECML the fleet of Mk4s is coming down though the HSTs still have about a month to go before they too return to their owner.

 

Of course if the RAIB found an issue so dangerous that immediate withdrawal is required then you would expect it would happen, otherwise it will be restrictions followed by rectifications to resolve any shortcomings highlighted when the RAIB report.

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5 hours ago, russ p said:

 

Just got this, seems they are concerned about the crash worthiness of the 800

It still strikes me as one heck of a lot of damage for a possible 9mph impact speed particularly if both trains were moving.  However I note they have not quoted firm speeds as yet and presumably that would be available from any on train data gathering on the IET if not for the HST?

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58 minutes ago, The Stationmaster said:

It still strikes me as one heck of a lot of damage for a possible 9mph impact speed particularly if both trains were moving.  However I note they have not quoted firm speeds as yet and presumably that would be available from any on train data gathering on the IET if not for the HST?

Presumably it might also show if the quoted 14 mph was a steady speed, or whether a brake application had reduced speed to that number at the moment of impact?

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On 15/11/2019 at 22:28, APOLLO said:

Is that the bog outlet pipe ?

 

Brit15

Hi Brit,

 

If it is I doubt it would cope with the aftereffects of a babie's 'ead and chips !

 

Gibbo.

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Hi Folks,

 

Having read through all of the comments so far and looked at the relevant photographs, it seems to me that the coupling bar itself is as follows:

  1. Has a relatively small section dimensionally, especially so in regard its length.
  2. Not of a particularly thick section, ie. tube wall thickness.
  3. Has a long dimension from connection point to the pivot point.
  4. Appears to be relatively unsupported in regard to its length.
  5. Does not appear to have any damping mechanisms to maintain alignment.

In view of the above points and various remarks about Mk 2, 3 & 4 coaching stock, buckeye couplings and also articulated designs, it would seem that the coupling device is somewhat pared down in both section and weight of material used by way of comparison. The draw hooks of Mk 3's from which  the buckeye couplings are attached are not actually that long, made form solid forged steel and are for most of their length housed within a tunnel in the drag box containing yaw damping with very little clearance for any amount of pitch. This does not seem to be the case in the case of the couplings of the 800's, these seem by comparison flimsy and rather exposed.

 

Does anyone have any information about the likely-hood of plastic deformation of the coupling bar under compression loading, and if so would that likely contribute to derailment in any way ?
 

Could it be that due to length and section of the coupling bars that they act like a pole vaulter's pole by flexing under load, springing back to shape and somehow pitching the bogies off the track ?

 

Another factor which has come to mind are the materials that the vehicles are made of and therefore the ability of the body shells to absorb shocks and vibrations when involved in collisions.

 

Gibbo.

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For the uninitiated, and because it's FRIDAY !!! 

 

CEgK2XQWEAEcohT.jpg

 

That lot would derail the Royal Scot !!

 

Brit15

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9 hours ago, adb968008 said:

We’re the both moving in the same direction though ?

 

RAIB statement indicates both were moving into the depot, so it would appear so.

 

9 hours ago, adb968008 said:

i’m kind of puzzled at the kind of puzzled comments about the crash and derailment...

 

Testing if something is crash worthy, is something you do in the design phase, and have signed off before you start manufacturing production examples.. or is that old fashioned thinking ?

 

Surely the behaviour observed, should therefore be the expected behaviour, even if it looks a bit unexpected to untrained eyes ?

 

The question is should the amount of derailment observed, with the potential for injury or worse if passengers had been moving between coaches, be expected for such a low speed collision.  If it is expected, that would seem to be a problem.

 

Obviously in a higher speed incident anyone in the gangway area is potentially going to be in trouble, but for a low speed collision the train should remain roughly aligned.

 

 

 

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It would seem that Mk3 and 4 stock as well as Pendolinos have performed very well in crashes over the years with regards to coupling integrity. The buckeyes are a lot to do with that.

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14 hours ago, The Stationmaster said:

It still strikes me as one heck of a lot of damage for a possible 9mph impact speed particularly if both trains were moving.  However I note they have not quoted firm speeds as yet and presumably that would be available from any on train data gathering on the IET if not for the HST?

 

13 hours ago, Oldddudders said:

Presumably it might also show if the quoted 14 mph was a steady speed, or whether a brake application had reduced speed to that number at the moment of impact?

I don't really want to speculate on this, but there is probably a big difference between a 9 mph slide into the HST in front, and a 9 mph "powered" collision. What if the driver had accidentally applied power instead of braking ?

 

Don't forget that LNER drivers in the West Riding have only relatively recently been driving the "single stick" 8xxs in service, compared to HSTs and 91s with separate power and rake controllers.    

Edited by Covkid

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15 hours ago, APOLLO said:

For the uninitiated, and because it's FRIDAY !!! 

 

CEgK2XQWEAEcohT.jpg

 

That lot would derail the Royal Scot !!

 

Brit15

You'll have to enlighten us true northerners? Baby's Yed 'n chips?

 

And WHY would anyone eat cod, when there's haddock available???????

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5 hours ago, Hobby said:

Pendos have buckeyes?

 

No, but the Mk3's do, and the buckeye has a long history of performing well too.

 

By the by, the Mk3 HST trailers have fixed buckeyes, in that there is just one solid coupling as opposed to being attached to a drawhook, which should make them stronger than a drophead. They also have a little extra bit at the bottom which helps prevent vertical separation too.

 

Also, this type of inter vehicle Dellner coupler has been in use for a long time - Introduced on the first build of Networkers, albeit probably a shorter length version. I suspect that it has been used on many other multiple unit trains built since...

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1 hour ago, JeffP said:

You'll have to enlighten us true northerners? Baby's Yed 'n chips?

 

And WHY would anyone eat cod, when there's haddock available???????

 

Baby's Yed = Steak and kidney pudding, served either "with crash helmet on" (the tin foil it is steamed in) to keep it warm, or "bawt crash helmet" to be instantly scoffed. Don't pour gravy over the baby's helmet though - sacrilege !!

 

Here is a bare baby's yed bawt crash helmet with chips, gravy and mushy peas. The correct way to serve. Eat your heart out Heston Blumenthal !!!!

 

levers-fish-chip-shop.jpg

 

Steak puds are found in all civilised chippys between Warrington and Wigan, We would die without our daily baby's yed !!

 

I agree re Haddock, a lot tastier than Cod, was more expensive a few years ago, actually cheaper now in most chippies.

 

Well, after that bit of culinary education back to the tin foil & plastic trains !!!!

 

Brit15

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3 hours ago, JeffP said:

You'll have to enlighten us true northerners? Baby's Yed 'n chips?

 

And WHY would anyone eat cod, when there's haddock available???????

Hi Jeff,

 

The depression in the bottom of a steak pudding resemble that of the fontanelle of a baby's head hence the name.

 

Gibbo. 

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On 22/11/2019 at 19:27, Gibbo675 said:

Hi Folks,

 

Having read through all of the comments so far and looked at the relevant photographs, it seems to me that the coupling bar itself is as follows:

  1. Has a relatively small section dimensionally, especially so in regard its length.
  2. Not of a particularly thick section, ie. tube wall thickness.
  3. Has a long dimension from connection point to the pivot point.
  4. Appears to be relatively unsupported in regard to its length.
  5. Does not appear to have any damping mechanisms to maintain alignment.

In view of the above points and various remarks about Mk 2, 3 & 4 coaching stock, buckeye couplings and also articulated designs, it would seem that the coupling device is somewhat pared down in both section and weight of material used by way of comparison. The draw hooks of Mk 3's from which  the buckeye couplings are attached are not actually that long, made form solid forged steel and are for most of their length housed within a tunnel in the drag box containing yaw damping with very little clearance for any amount of pitch. This does not seem to be the case in the case of the couplings of the 800's, these seem by comparison flimsy and rather exposed.

 

Does anyone have any information about the likely-hood of plastic deformation of the coupling bar under compression loading, and if so would that likely contribute to derailment in any way ?
 

Could it be that due to length and section of the coupling bars that they act like a pole vaulter's pole by flexing under load, springing back to shape and somehow pitching the bogies off the track ?

 

Another factor which has come to mind are the materials that the vehicles are made of and therefore the ability of the body shells to absorb shocks and vibrations when involved in collisions.

 

Gibbo.

I would be very surprised if the intermediate drawbars are not strong enough to take the end loads imposed in a collision without buckling. I would also expect them to be attached to the car body with both a degree of longitudinal springing and mountings that will absorb, through friction, hydraulic damping or controlled deformation, at least some of the energy that needs to be dissipated when the train collides with a (relatively) immovable object. When things become interesting is when the drawbars "bottom" their suspensions, ie become solid. A common factor in this incident is that the derailed bogies were all at the trailing ends of the cars affected. If you think about what happens when a train is stopped suddenly by an impact at the front end, all the cars will tend to pitch down at the leading end and rise at the trailing end. Each drawbar is now inclined upwards towards the front of the train, which will tend to further lift the back end of the carriage in front, potentiallby enough to lift the wheels momentarily off the track. If there is any slight curvature involved this will also tend to push the preceding carriages in an outward direction, and it will be noted from the RAIB's press release that all the derailed bogies/wheels departed the track in the same direction.

The behaviour of trains under derailment conditions is complex to say the least, as the final outcome can be compounded by factors that are outwith the designer's control. It is an area where, no matter how much computer simulation is done, there is no substitute from learning from actual events and whilst this one was quite tame by comparison with some collisions, both the RAIB and the industry will want to learn as much as they can from it.

 

Jim

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8 hours ago, jim.snowdon said:

I would be very surprised if the intermediate drawbars are not strong enough to take the end loads imposed in a collision without buckling. I would also expect them to be attached to the car body with both a degree of longitudinal springing and mountings that will absorb, through friction, hydraulic damping or controlled deformation, at least some of the energy that needs to be dissipated when the train collides with a (relatively) immovable object. When things become interesting is when the drawbars "bottom" their suspensions, ie become solid. A common factor in this incident is that the derailed bogies were all at the trailing ends of the cars affected. If you think about what happens when a train is stopped suddenly by an impact at the front end, all the cars will tend to pitch down at the leading end and rise at the trailing end. Each drawbar is now inclined upwards towards the front of the train, which will tend to further lift the back end of the carriage in front, potentiallby enough to lift the wheels momentarily off the track. If there is any slight curvature involved this will also tend to push the preceding carriages in an outward direction, and it will be noted from the RAIB's press release that all the derailed bogies/wheels departed the track in the same direction.

The behaviour of trains under derailment conditions is complex to say the least, as the final outcome can be compounded by factors that are outwith the designer's control. It is an area where, no matter how much computer simulation is done, there is no substitute from learning from actual events and whilst this one was quite tame by comparison with some collisions, both the RAIB and the industry will want to learn as much as they can from it.

 

Jim

Hi Jim,

 

Very interesting points in your answer, all of which make perfect sense.

 

I agree you are correct that the length of the draw bars and possibly also the length of the vehicles themselves may well be a factor in the derailment of the bogies especially should the longitudinal damping arrangements bottom out. Your scenario of reasoning of the likely reactions are also equally plausible, as you say when the draw bar damping is bottomed out and the whole train effectively becomes solid then the only route to dissipate the energy to be absorbed is for the vehicles to rotate thus causing derailment as we may well have seen.

 

With regard the strength of the draw bars, the British buckeyes are 3/4 sized versions of the American buckeyes which were themselves designed to take huge loads. Could it be that the British buckeyes are effectively over specified for use in passenger trains compared with the original designs use in 4000 ton plus freight trains ? If this is the case then this may well be why the draw bars of the 800 look light weight in comparison. My other thought on the subject is that the drag box of the 800 will be aluminium and may also be a factor in how strong the draw bar is to be made for it would be preferable to sacrifice the draw bar by way of deformation rather than damage the body shell in a collision.

 

The one thing to note is that irregardless of direction of travel both the HST and the 800 were subject to the same impulse force yet the HST came off somewhat better. Was the alignment of the track under the 800 such to cause it to be a contributory factor ?

 

Cheers,

 

Gibbo.

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8 hours ago, Gibbo675 said:

The one thing to note is that irregardless of direction of travel both the HST and the 800 were subject to the same impulse force yet the HST came off somewhat better. Was the alignment of the track under the 800 such to cause it to be a contributory factor ?

Don't know, but the 70 tonne mass of the HST power car would be an influencing factor.

 

8 hours ago, Gibbo675 said:

With regard the strength of the draw bars, the British buckeyes are 3/4 sized versions of the American buckeyes which were themselves designed to take huge loads. Could it be that the British buckeyes are effectively over specified for use in passenger trains compared with the original designs use in 4000 ton plus freight trains ? If this is the case then this may well be why the draw bars of the 800 look light weight in comparison. My other thought on the subject is that the drag box of the 800 will be aluminium and may also be a factor in how strong the draw bar is to be made for it would be preferable to sacrifice the draw bar by way of deformation rather than damage the body shell in a collision.

How to provide progressive energy absorbtion in the event of an end on collision is not something with a simple answer. Ideally, there is a hierarchy in proportion to the speed of impact and thus the energy to be dissipated, starting with the longitudinal springing in the drawbar mountings. After that, the usual approach is to provide deformable elements in the drawbars, the idea being that these should cope with the majority of minor impacts (which would usually be in the class of braking misjudgements approaching buffer stops and whilst coupling to other units). Next would be progressive deformation of the drawgear mountings and last (and hopefully only rarely) is progressive collapse of the car body shell. Somewhere in all of this is the need, following a destructive impast, to be able to recover the vehicles, preferably on their own wheels, using the now damaged drawgear.

 

Jim

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