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GWR withdraw some 800's due to cracks (ORR Report now published)

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D365

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All this makes me think a train with a power car at either end, both electric and diesel capable would have been far more effective than what we have with 80x. If only HST2 had come to fruition.
How would that have made a difference in any way.
 
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irish_rail

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How would that have made a difference in any way.
Well for one thing extending them by making additional coaches would no doubt be cheaper as you'd just be building a bog standard trailer not an all singing all dancing powered vehicle. And the amount of 5 car sets on GWR is a problem.
 

D365

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Well for one thing extending them by making additional coaches would no doubt be cheaper as you'd just be building a bog standard trailer not an all singing all dancing powered vehicle. And the amount of 5 car sets on GWR is a problem.
Not sure how that solves or mitigates the issue of cracking in the yaw damper bolsters.
 

Peter Sarf

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Well for one thing extending them by making additional coaches would no doubt be cheaper as you'd just be building a bog standard trailer not an all singing all dancing powered vehicle. And the amount of 5 car sets on GWR is a problem.
Yaw damper cracking aside. Extending HST style trains with trailers is EXACTLY the same as making non-powered trailers for the 5-car IETs on GWR. In both cases the power to weight ratio declines. Advantage of an IET is you can add a mixture of trailers and powered coaches to maintain the power to weight ratio. But I still prefer HSTs !.
 

irish_rail

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Yaw damper cracking aside. Extending HST style trains with trailers is EXACTLY the same as making non-powered trailers for the 5-car IETs on GWR. In both cases the power to weight ratio declines. Advantage of an IET is you can add a mixture of trailers and powered coaches to maintain the power to weight ratio. But I still prefer HSTs !.
But additional vehicles for 802s would need to be powered vehicles. Trailers would put too much pressure on the existing 3 engines. Whereas with two hefty engines either end an additional couple of carriages shouldn't make too much difference to performance.
 

Nym

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How would that have made a difference in any way.

Well for one thing extending them by making additional coaches would no doubt be cheaper as you'd just be building a bog standard trailer not an all singing all dancing powered vehicle. And the amount of 5 car sets on GWR is a problem.

Except that in the world of modern units, it's not as simple as shove another coach in. Especially with the way that the more 'advanced' systems are integrated, it takes four hours and five laptops to add another Mk.4 into a rake for example with all of the equipment that needs adjusting (that has been added).

If the design specification for "HST2" included a mandating to minimise the number of unique vehicles, and possibly still included a distributed traction system then it would have been a lot less of an issue.
 

Horizon22

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So, what will it take to fix this? What will be the cost in £ and units out of service?

Nobody knows how much it will cost yet. This presumably depends on how much Hitachi accept responsibility. A small number of units have already been returned to service which have had welding repairs.
 

Wilts Wanderer

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But additional vehicles for 802s would need to be powered vehicles. Trailers would put too much pressure on the existing 3 engines. Whereas with two hefty engines either end an additional couple of carriages shouldn't make too much difference to performance.

Don’t ever attempt a career in timetabling.
 

800001

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Except that in the world of modern units, it's not as simple as shove another coach in. Especially with the way that the more 'advanced' systems are integrated, it takes four hours and five laptops to add another Mk.4 into a rake for example with all of the equipment that needs adjusting (that has been added).

If the design specification for "HST2" included a mandating to minimise the number of unique vehicles, and possibly still included a distributed traction system then it would have been a lot less of an issue.
4 hours to add a Mk4? You sure?
 

coppercapped

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Nobody knows how much it will cost yet. This presumably depends on how much Hitachi accept responsibility. A small number of units have already been returned to service which have had welding repairs.
I would suggest that there are two major issues here.

Firstly, what will be total cost of the repairs/rework and, secondly, how will these costs be allocated?

The answer to the first part is that, at the moment, nobody knows either the total costs or the timescales as neither the methods of repair nor the extent of the repairs have been defined or agreed.

The answer to the second part is also not clear as the trains supplied by Agility Trains to meet the requirements of the contracts for the Intercity Express Programme are owned by Agility Trains. One would expect the owner to have to pay for the repairs to its property[1]. How the costs for repairs are divvied up between Hitachi and the rolling stock owning groups for those trains purchased subsequent to the IEP is, I suspect, being negotiated at the moment.

[1] As one of the major reasons of the structure of the IEP was to pass the design, manufacturing and operational risks to the train supplier (Agility) and the manufacturer (Hitachi) one would hope that the DfT remains true to its principles. Otherwise what was the point of the IEP contract? However I can see that in any future renegotiation of part of or of the whole IEP contract Agility may ask for a higher payment for the use of the trains. If the DfT agrees then this would mean that the train operators would almost certainly pass on the higher costs to their passengers unless the DfT indemnifies them.

As I wrote in an earlier post - this will run and run.
 

Anonymous10

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Nobody knows how much it will cost yet. This presumably depends on how much Hitachi accept responsibility. A small number of units have already been returned to service which have had welding repairs.
sorry I haven't been following this are they still operating on reduced services for this or using trains before they are repaired or was it only a few units
 

Horizon22

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sorry I haven't been following this are they still operating on reduced services for this or using trains before they are repaired or was it only a few units

GWR need approximately 65 IET diagrams to run their current service in booked formations, which isn't always being supplied on a daily basis but its normally there or there abouts. It's still stripped back but considering the timetable has changed about 6 times since Dec '19 anyway its difficult to exactly define 'reduced'!. The major one is that there's very few direct Paddington - Bedwyn services (although these were also reduced in the first lockdown) and rare direct services between Paddington - Cardiff (again had been reduced since the pandemic started). To compensate somewhat, GWR are running more 387 services (see here & here) which can currently run in passenger service as far as Bristol Parkway on a few diagrams.
 

Irascible

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Nobody knows how much it will cost yet. This presumably depends on how much Hitachi accept responsibility. A small number of units have already been returned to service which have had welding repairs.
Presume these are patch repairs to hold over until there's a comprehsnsive program, though - it's looking like they'll all need surgery, currently affected or not?

Just hope this doesn't just transfer stress somewhere else & put that over a limit too...
 

coppercapped

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Presume these are patch repairs to hold over until there's a comprehsnsive program, though - it's looking like they'll all need surgery, currently affected or not?

Just hope this doesn't just transfer stress somewhere else & put that over a limit too...
The cracking is not due to stress alone, but to a combination of chemical reactions occurring in the microcracks as the structure is stressed. The type of alloy being used requires heat treatment of the weld zone after welding, so just patching it may help for a year or two, but then the problem is quite likely to resurface.

This document by the National Physical Laboratory gives an outline to control of stress corrosion https://www.iims.org.uk/wp-content/uploads/2014/03/stress_corrosion_cracking.pdf Section 4.6 briefly covers high strength aluminium alloys such as those used by Hitachi.

So, yes, it is quite possible that all the trains built to date will need treatment sooner or later.
 

MotCO

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I would suggest that there are two major issues here.

Firstly, what will be total cost of the repairs/rework and, secondly, how will these costs be allocated?

Is there another question which still needs to be addressed? What is the root cause of the problem? Yes, the ORR report referred to corrosion due to the British climate once the cracks occurred, but was the underlying cause identified?

If correct, then until the underlying cause is identified, can the permanent repairs carried out?
 

GC class B1

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Is there another question which still needs to be addressed? What is the root cause of the problem? Yes, the ORR report referred to corrosion due to the British climate once the cracks occurred, but was the underlying cause identified?

If correct, then until the underlying cause is identified, can the permanent repairs carried out?
I read the ORR report and my understanding was that the lifting point cracks resulted from Stress Corrosion Cracking as a result of the corrosion not the other way round.

The cracking is not due to stress alone, but to a combination of chemical reactions occurring in the microcracks as the structure is stressed. The type of alloy being used requires heat treatment of the weld zone after welding, so just patching it may help for a year or two, but then the problem is quite likely to resurface.

This document by the National Physical Laboratory gives an outline to control of stress corrosion https://www.iims.org.uk/wp-content/uploads/2014/03/stress_corrosion_cracking.pdf Section 4.6 briefly covers high strength aluminium alloys such as those used by Hitachi.

So, yes, it is quite possible that all the trains built to date will need treatment sooner or later.
The report seemed to state that the lifting bracket cracks had occurred because of stress corrosion cracking with the stresses being inherent in manufacture and not resulting from service. It also stated that the cracks did not seem to be growing. Is it therefore possible that welding the cracks would introduce even more stress and leaving the cracks as they are is a better option. The fact they are not growing could suggest that the stresses have now been relieved and one element necessary for SCC has been eliminated. The downside is continuing monitoring but could this be a better option.
 
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Clarence Yard

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The ORR report is, of necessity, diplomatic as the originating cause of the cracking is in dispute, especially regarding the bolsters.

The material specified and method of construction is where the focus should be. The environmental conditions that prevail in this country should be no surprise to anyone but once you have SCC (or fatigue cracks) you are always going to make things worse by operating them. The key here is what the real propagation rate and when, if at all, do you reach catastrophic failure mode? At the moment it seems that rate is very slow.

All but 2 of those GWR units stopped in April/May have re-entered service but there is a constant churn of units being failed and either being released back into service under concession or receiving welding repairs. Eventually every unit will need repairs of one sort or another.

But, once the long term fix has been identified, it shouldn’t require too many units out of traffic at any one time.
 

Peter Sarf

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But additional vehicles for 802s would need to be powered vehicles. Trailers would put too much pressure on the existing 3 engines. Whereas with two hefty engines either end an additional couple of carriages shouldn't make too much difference to performance.
Do you really believe the HSTs were overpowered ?. They were not. Worse still they were already slowed down by the extra trailers added decades ago.

Not that the power to weight ratio has anything to do with the subject of the thread.
 

dgl

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One thing I do understand is that any repair to the current bodyshells will mean that the length of time they were rated to be in service for will be reduced, I don't know by how much but as I understand it the heating caused by welding damages the materials reducing their useful life.

So whatever the fix seems to be it seems the trains will have a reduced service life.
 

Clarence Yard

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It’s not the bodyshell that is the problem. It’s the bolster welded on underneath it that has the issue. The bodyshell itself is sound.
 

dgl

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If it's OK to post it here going by what Tony Miles has said on WNXX the general conclusion form the experts in the field that bodyshell replacement is probably going to be the cheapest solution, not necessarily because of how much it costs to sort the cracks, or the supposed shorter life of the trains because of the stresses caused by welding, but because of the validation required after a crack has been fixed/welded, and putting your name to a fix like that is going to cost, esp. because of the already known issues over weld integrity.
Supposedly Hitachi have been told that a temporary welding fix is not a permanent solution.

Looks like some banks are starting to get a bit worried that their 27+ year cash cow might be anything but.

The view across experts in the field is that now the sections have been ground out it's just not economical to try to repair them and new bodyshells would be quicker and cheaper. If they attempt to weld them they'll presumably need some way of validating the welds - which is tricky when there's already concern about weld integrity etc....
 
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800001

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If it's OK to post it here going by what Tony Miles has said on WNXX the general conclusion form the experts in the field that bodyshell replacement is probably going to be the cheapest solution, not necessarily because of how much it costs to sort the cracks, or the supposed shorter life of the trains because of the stresses caused by welding, but because of the validation required after a crack has been fixed/welded, and putting your name to a fix like that is going to cost, esp. because of the already known issues over weld integrity.
Supposedly Hitachi have been told that a temporary welding fix is not a permeant solution.

Looks like some banks are starting to get a bit worried that their 27+ year cash cow might be anything but.

If it's OK to post it here going by what Tony Miles has said on WNXX the general conclusion form the experts in the field that bodyshell replacement is probably going to be the cheapest solution, not necessarily because of how much it costs to sort the cracks, or the supposed shorter life of the trains because of the stresses caused by welding, but because of the validation required after a crack has been fixed/welded, and putting your name to a fix like that is going to cost, esp. because of the already known issues over weld integrity.
Supposedly Hitachi have been told that a temporary welding fix is not a permeant solution.

Looks like some banks are starting to get a bit worried that their 27+ year cash cow might be anything but.

On Thursday night Agility Trains and Hitachi submitted to the
Department for Transport their formal plan for rectifying the
cracks in the Class 800 series trains. This plan is now being
reviewed by DfT, their technical advisors and the train
operators.
 

dgl

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On Thursday night Agility Trains and Hitachi submitted to the
Department for Transport their formal plan for rectifying the
cracks in the Class 800 series trains. This plan is now being
reviewed by DfT, their technical advisors and the train
operators.
Though supposedly Hitachi still don't yet know what is causing the cracks or how quickly they are propagating/occurring, so I'm guessing Hitachi are just trying to buy some more time by saying they have a solution only for it to be thrown out, they BS up some excuse that the government fall for and they get more time.
 

irish_rail

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If it's OK to post it here going by what Tony Miles has said on WNXX the general conclusion form the experts in the field that bodyshell replacement is probably going to be the cheapest solution, not necessarily because of how much it costs to sort the cracks, or the supposed shorter life of the trains because of the stresses caused by welding, but because of the validation required after a crack has been fixed/welded, and putting your name to a fix like that is going to cost, esp. because of the already known issues over weld integrity.
Supposedly Hitachi have been told that a temporary welding fix is not a permanent solution.

Looks like some banks are starting to get a bit worried that their 27+ year cash cow might be anything but.

Too be clear i think the journalist is referring to the unit (800026????) that has been cut up in order to sample the metal. He is not suggesting the entire fleet receive new bodyshells .
 

XAM2175

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Though supposedly Hitachi still don't yet know what is causing the cracks or how quickly they are propagating/occurring, so I'm guessing Hitachi are just trying to buy some more time by saying they have a solution only for it to be thrown out, they BS up some excuse that the government fall for and they get more time.
I was under the impression that it was known to be stress corrosion cracking and that the rate of propagation is now reasonably well known due to the measurements obtained by running units with special sensors.

The idea of every civil servant on the project being so lackadaisical that they "fall for some BS excuse" is what strikes me as the BS.
 

43096

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The idea of every civil servant on the project being so lackadaisical that they "fall for some BS excuse" is what strikes me as the BS.
They fell for the BS of the whole IEP project, with its contract terms weighted in Agility's favour, so why would that change now? Civil servants shouldn't be involved with anything related to train engineering, let alone designing the trains.
 
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