Northern withdraws some CAF trains due to yaw bracket failures

Energy

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Not really. The last two fleets TfL bought are similar levels of low quality.
Indeed, previously TfL purchased all its stock from Bombardier. Following the 345s and particularly the 710s they have ordered from other manufacturers, such as CAF for the DLR and Siemens for the NTfL. I would imagine CAF may have been chosen by TfL (and Northern) due to price.
 
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mightyena

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As I've said elsewhere the only major problem with Class 170s is that they didn't build roughly twice as many of them.
I'd say the main flaw of the 170s is that their acceleration is measured on a geological timescale. Fine when they're used on longer distance services with limited stops, but they so often aren't
 

hexagon789

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Buy cheap, buy twice, as the saying goes!
Quite!

So am I!

It may well be the 22 highest mileage or 22 that have operated on more challenging routes most often that have failed so far.

As so as it start to go they will go moderately quickly.
I suspect more will be withdrawn in the near future, while they are of course doing extra checks, without an actual re-design of the mountings the same failure point still exists.


It does raise the interesting question of what happened in the intervening time to make these so much worse than the DMUs they built for NIR.
In general terms or specifically related to the running gear?
 

edwin_m

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CAF were also responsible for the mechanical parts of the 332s and 333s, including the running gear. I don't recall them having any ride-related problems.
 

DustyBin

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I'm old enough to remember when the 158s when new had cracking of the similar yaw damper bracket and had to return to works for a much more substantial one to be fitted.
Pic attached of a 158 bogie
Note the replacement bracket (the one with the hole in) extends up the body side and looks to be welded or bonded to the side.
How or if you can weld steel to aluminium I know not.
K

Looking at that photograph I’d say that everything painted in body colour(s) is aluminium and the lower black painted part is steel, with the two joined using mechanical fixings. I don’t know that for a fact, just an educated guess.

There are some clever processes for welding steel to aluminium, there looks to have been an easier solution here though.
 

py_megapixel

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CAF were also responsible for the mechanical parts of the 332s and 333s, including the running gear. I don't recall them having any ride-related problems.
Other way round IIRC. CAF did the bodies, Siemens did the running gear.

I'm old enough to remember when the 158s when new had cracking of the similar yaw damper bracket and had to return to works for a much more substantial one to be fitted.
Was the ride quality of the 158 significantly worse before that work was done? I'd assume not, but if it was then perhaps we can be hopeful that whatever modifications have to be made to the 195s will make them less rough
 

py_megapixel

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Running gear in that context was motors & associated electronics. The physical bogies were CAF (you can see the logo stamped on them at several points in this picture)
Right, fair enough.

I mean, the 331s do still ride a lot better than the 195s, so maybe the weight of the motors vice the diesel engines does have something to do with it? I'm certainly no expert in this regard.
 

edwin_m

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I mean, the 331s do still ride a lot better than the 195s, so maybe the weight of the motors vice the diesel engines does have something to do with it? I'm certainly no expert in this regard.
Interesting thought. The traction motors are attached to the bogie whereas the diesel is body-mounted and drives via a cardan shaft, so the bogie is probably quite a bit heavier in the 331. That might make it less likely to thrash around, although if it does so there might be greater forces involved.
 

AlexNL

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If memory serves me right some of the CAF trains were manufactured in Spain, and others in Wales. Could this issue be related to a manufacturing defect tied to a specific plant, or is it a wider design issue?
 

py_megapixel

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If memory serves me right some of the CAF trains were manufactured in Spain, and others in Wales. Could this issue be related to a manufacturing defect tied to a specific plant, or is it a wider design issue?
Wasn't all of Northern's order actually done in Spain (as Newport wasn't open when the order was placed)?

There is a 195 that has been to Newport subsequently due to damage from a collision (or something like that anyway).
 

Energy

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Wasn't all of Northern's order actually done in Spain (as Newport wasn't open when the order was placed)?

There is a 195 that has been to Newport subsequently due to damage from a collision (or something like that anyway).
One 331 was built at Newport to prove it can build EMUs, some 195s were built at Newport.
 

skyhigh

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There is a 195 that has been to Newport subsequently due to damage from a collision (or something like that anyway).
195021 went back to Newport after being damaged in a depot derailment before entering service.
 

superkev

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Right, fair enough.

I mean, the 331s do still ride a lot better than the 195s, so maybe the weight of the motors vice the diesel engines does have something to do with it? I'm certainly no expert in this regard.
I find that although the 331s ride a little better there are still bangs and thumps coming from the underside presumably as the suspension hits the bump stops.
All the recent CAF stuff sounds to be shaking itself apart.
K
 

Bletchleyite

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I find that although the 331s ride a little better there are still bangs and thumps coming from the underside presumably as the suspension hits the bump stops.
All the recent CAF stuff sounds to be shaking itself apart.

It's not ideal, but some stock has survived well despite this. On jointed rail sections (not many left now, but there were for years) 507s and 508s would bounce along on the bump stops the whole time, but have lasted perfectly well.
 

coppercapped

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I'm old enough to remember when the 158s when new had cracking of the similar yaw damper bracket and had to return to works for a much more substantial one to be fitted.
Pic attached of a 158 bogie
Note the replacement bracket (the one with the hole in) extends up the body side and looks to be welded or bonded to the side.
How or if you can weld steel to aluminium I know not.
K

Other way round IIRC. CAF did the bodies, Siemens did the running gear.


Was the ride quality of the 158 significantly worse before that work was done? I'd assume not, but if it was then perhaps we can be hopeful that whatever modifications have to be made to the 195s will make them less rough
The bodies of the 158s were the first large scale use of extruded aluminium planks and as a result there was still quite a lot of learning involved.

The welds holding the yaw damper bracket to the body cracked due to the number and amplitude of the stress reversals as the bogie rotated about its vertical centre when running at speed. Although there had been some use of hydraulic yaw dampers previously most bogies until that date either did not have to use them because the trains' speeds were not high enough or used a disc of friction material around the centre pivot. Earlier stock tended to have steel bodies. The modified brackets in the 158s spread the stresses over a wider area.

There was no difference in the ride quality in the 158 after the modification - in both cases the bracket did its job except that the lifetime of the welds in the unmodified form was too short!

The other early snag with the 158s was cracking in the top corners of the door openings. Again a retrospective modification programme was needed.

I'm asking because I don't know - do any of the CAF products in other countries spend much of their time running at more than 75mph or thereabouts? The stresses get significant as the forces on the bogies increase and it may be that CAF's experience in this area is limited.

But, my word, other stock has had problems as well which caused withdrawal from service. :( After some 120 years of experience the driving wheels and axles on BR's Britannia class steam locomotives went round at different speeds which caused some anguish and they were grounded until the problem was sorted out. Some early ac electric multiple units also had problems as did some classes of diesel-hydraulics. Twas ever thus...
 

ic31420

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The interesting question is whether the failure is due to poor design, material failure or poor quality control. None of those are great but some are potentially much more concerning than others.
I think there is potentially another possibly. That being the design is as specified, but the units are seeing forces greater than specified to deal with.

Faulty spec if you like.

I'd like to think the materials are well understood and the stress / fatigue modelling well understood these days.


I use an awful IT system daily that was poorly specified and built to the poor spec with no forward view or apparently no tech thought. Resulting in a system that was deployed 18 months ago and won't operate in anything newer than windows 7 or IE 11, and only sensibly at on a certain size monitor resolution at 100% scale. The supplier simply says we built what was in your spec. We can change it but it'll cost you.
 

Bletchleyite

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I don't know about trains, but a good IT supplier questions a bad spec, this is not only good customer service but also provides the potential for upselling to something better than originally specified.
 

py_megapixel

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I don't know about trains, but a good IT supplier questions a bad spec, this is not only good customer service but also provides the potential for upselling to something better than originally specified.
Presumably in the context of rolling stock orders, anyone who bids a higher quality product will inevitably be undercut by another bidder who designs their bid to just meet the spec. And because of the rules previously mentioned, that cheaper bidder has to be chosen even if it would be a worse long-term decision. So nobody does.
 

coppercapped

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Presumably in the context of rolling stock orders, anyone who bids a higher quality product will inevitably be undercut by another bidder who designs their bid to just meet the spec. And because of the rules previously mentioned, that cheaper bidder has to be chosen even if it would be a worse long-term decision. So nobody does.
I think you will find that the rules you previously mentioned apply only to purchases made by public bodies such as Network Rail. Trains which are purchased by the Rolling Stock companies do not fall under this umbrella as the ROSCOs are private companies.

Also many recent purchases have been instigated by TOCs using asset management or financial houses and these organisations do not have the depth of engineering support that is supplied by the ROSCOs so the TOCs using this approach have to supply their own engineering expertise. TOCs were only ever intended to be operators, not engineers so this engineering expertise (as distinct from maintenance expertise) may be a bit lacking.
 

fgwrich

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Running gear in that context was motors & associated electronics. The physical bogies were CAF (you can see the logo stamped on them at several points in this picture)

Interestingly, that body / bogie combination still seems to be available from CAF, as they are building more vehicles of it for the NIR 4000 Class Extension program. Why oh why they switched to the much derided Civity UK design I don't know, as both UK and NIR CAF Fleets are excellent to travel in.
 

superkev

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Both the CAF / Seimens 333s and the now withdrawn 332's have had structural issues around the bogie to body interfaces. Was it 333 007 which spent over a year at the Railway technical centre over this issue so all may not be well with older CAF units too.
K
 

edwin_m

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Presumably in the context of rolling stock orders, anyone who bids a higher quality product will inevitably be undercut by another bidder who designs their bid to just meet the spec. And because of the rules previously mentioned, that cheaper bidder has to be chosen even if it would be a worse long-term decision. So nobody does.
It's possible to include quality criteria in a public tender, provided the basis on which quality and price are scored and weighted is made clear.
 

Nymanic

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Why oh why they switched to the much derided Civity UK design I don't know, as both UK and NIR CAF Fleets are excellent to travel in.
I suspect it's to keep the overall weight down. Lower track access charges, and light enough to run to SP differentials.

CAF's lack of experience with inside frame bogies seems painfully evident.

I don't think I've seen the Civity bogie design anywhere else. Maybe it's like the Fainsa 'ironing board' - conceived for the UK market, and its fixation on low cost/weight.

Who knows, maybe the bogies will get swapped out in a few years for something that works (Flexx Eco), or something conventional - if the trains last that long!
 

Irascible

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I use an awful IT system daily that was poorly specified and built to the poor spec with no forward view or apparently no tech thought. Resulting in a system that was deployed 18 months ago and won't operate in anything newer than windows 7 or IE 11, and only sensibly at on a certain size monitor resolution at 100% scale. The supplier simply says we built what was in your spec. We can change it but it'll cost you.

I don't know about trains, but a good IT supplier questions a bad spec, this is not only good customer service but also provides the potential for upselling to something better than originally specified.
If you look into procurement ( especially govt ) you'll find stories of this everywhere - one of the most high profile is probably the aircraft carriers. Contempt for customers goes all the way up...
 

Wolfie

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Interestingly, that body / bogie combination still seems to be available from CAF, as they are building more vehicles of it for the NIR 4000 Class Extension program. Why oh why they switched to the much derided Civity UK design I don't know, as both UK and NIR CAF Fleets are excellent to travel in.
Cost and possibly weight at a guess. There were issues with both the 332s and 333s too

It's possible to include quality criteria in a public tender, provided the basis on which quality and price are scored and weighted is made clear.
Possible, yes. Getting HMT agreement....
 

MisterT

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Interesting to read about this issue. Here in the Netherlands, I've not heard about this particular issue being a problem with our CAF Civity fleet, but it seems like exactly this mounting point has been changed between the first series (118 units) and the second series (another 88 units). My best guess is that it might have been spotted as a potential weak place and has been changed.
The upper unit is one of the first series, and the lower unit is a new one from the second batch, from which the first train was delivered about a year ago.


Picture from the bogies of two different CAF Civity 'Sprinter New Generation' units

Picture via Facebook
 

Wolfie

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Interesting to read about this issue. Here in the Netherlands, I've not heard about this particular issue being a problem with our CAF Civity fleet, but it seems like exactly this mounting point has been changed between the first series (118 units) and the second series (another 88 units). My best guess is that it might have been spotted as a potential weak place and has been changed.
The upper unit is one of the first series, and the lower unit is a new one from the second batch, from which the first train was delivered about a year ago.


View attachment 94126

Picture via Facebook
Definitely looks significantly meatier, TY.
 

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