Northern withdraws some CAF trains due to yaw bracket failures

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scrapy

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I dont think any of the east sides 4 car 331s are affected (yet) for some reason.
Perhaps the east side routes being relatively straight are not as taxing on the yaw damper mounts.
K
Haven't quite a few of the 331s spent similar amount of time on either side of the Pennines with the 4 cars initially on the west and the 3 cars initially on the east?
 

edwin_m

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Wonder if the length of the train has a bearing on stress between the bogies and frame? The longer the train the greater the area to absorb the forces as the stress passes through the train.

It would be really funny if CAF designed the yaw damper mounting based on the stresses on a 4 car unit and never checked with shorter formations.
The longitudinal forces from acceleration and braking will be transmitted between the bogies and the train by other means. The yaw dampers are essentially shock absorbers that dampen down the rapid rotation of the bogie that is one cause of poor riding, while hopefully not much affecting the slower rotations as it goes into and out of curves. I can't see that this sort of force and movement would depend much on train length.
 

Jamesrob637

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Haven't quite a few of the 331s spent similar amount of time on either side of the Pennines with the 4 cars initially on the west and the 3 cars initially on the east?

Kind of. Wharfe and Airedale lines were meant to go 6-car and may yet still do.
 

Irascible

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The longitudinal forces from acceleration and braking will be transmitted between the bogies and the train by other means. The yaw dampers are essentially shock absorbers that dampen down the rapid rotation of the bogie that is one cause of poor riding, while hopefully not much affecting the slower rotations as it goes into and out of curves. I can't see that this sort of force and movement would depend much on train length.
Might get a bit more overall lateral movement at the ends that aren't coupled to something ( and maybe a bit more hunting as a result ) but that doesn't seem like something that'd cause a disastrously greater amount of stress on the bracket.

I have no idea how the maintenance is broken down for all these units, are they looked after in different places?
 

Neptune

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Haven't quite a few of the 331s spent similar amount of time on either side of the Pennines with the 4 cars initially on the west and the 3 cars initially on the east?
A few 3 cars were initially in the east for training purposes only. None have worked passenger services in the east.
 

edwin_m

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Might get a bit more overall lateral movement at the ends that aren't coupled to something ( and maybe a bit more hunting as a result ) but that doesn't seem like something that'd cause a disastrously greater amount of stress on the bracket.

I have no idea how the maintenance is broken down for all these units, are they looked after in different places?
If so then it would apply mostly to the bogies at each end of the set, which would be proportionately more failures in the shorter sets but the actual failure risk per end bogie is unlikely to be different.
 

js1000

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Having travelled extensively on both the 195 and 331s since their introduction in July 2019 this is not hugely surprising. The interior is a vast upgrade on existing Northern stock, but the ride quality on the 195 over points particularly is atrocious. The 331 is smoother but not by much. It is noticeable the lack of CAF units about - 319s and 156s are now covering these missing units on many routes in/out of Manchester at the moment. Hopefully they can sort these units before upscaling of services as part of the May timetable.

I know there are discussions surrounding warranty issues but it would certainly not just be a "12 months and it's up" arrangement. Eversholt would have ensured their are appropriate contractual safeguards in place to cover any widespread issue once in service. For instance, there is a limitation period of 6 or 12 years depending on if a contract was signed under hand or under deed for items that cost millions such as buildings, trains etc in case of breach of contract. This excludes separate warranty and maintenance care plans that are usually agreed as well to service the trains over the course of their use.
 
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D6130

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There were certainly a large number of 195 substitutions on the Calder Valley line yesterday. In the space of less than an hour at Hebden Bridge, I noted three trains which would normally be booked for 195s being worked by a 2 car 158+153, a 3 car 158 and a pair of 150s respectively.
 

Killingworth

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We had 2 out of 3 stopping services on the Hope Valley line operated by 195s until the latest service reductions. We thought we'd be getting them back from May but seems it's to remain 150s UFN.

In truth that's possibly better in that we're getting 4 car trains and at weekends they can get quite busy - much more than commuting services at present. (A shame Northern can't marshall pairs of 150/2s rather than a 150/1 and 150/2 preventing walk through access. That would help to even out loads and improve revenue collection along the whole train - subject for another thread!)
 

skyhigh

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There were certainly a large number of 195 substitutions on the Calder Valley line yesterday. In the space of less than an hour at Hebden Bridge, I noted three trains which would normally be booked for 195s being worked by a 2 car 158+153, a 3 car 158 and a pair of 150s respectively.
The 158+153 is a booked working.
 

skyhigh

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1J19, 14 12 LDS-MCV?
Yes, it's been booked 158+153 for a while, certainly since the reduced timetable came in. I've worked it myself a few times (there's also an inwards trip in the AM from Vic - 1J06, it goes onto Neville Hill for a few hours after arrival before coming back out. It's 153324+158868 today).
 

D6130

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Yes, it's been booked 158+153 for a while, certainly since the reduced timetable came in. I've worked it myself a few times (there's also an inwards trip in the AM from Vic - 1J06, it goes onto Neville Hill for a few hours after arrival before coming back out. It's 153324+158868 today).
Fair enough....I hadn't realised that. It was 158 868+153 324 yesterday too.
 

skyhigh

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Fair enough....I hadn't realised that. It was 158 868+153 324 yesterday too.
Was the 3 car 158 on a Wigan service? 158s (or 150s) are the booked traction on those too. The 150x2 is definitely a planned substitution for 195 availability though.
 

AgentGemini

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Little bit of a distraction perhaps, but my insider at WMT is informing me that apparently some of the abellio 196s are having to be grounded for exactly the same fault.
 

southern442

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Little bit of a distraction perhaps, but my insider at WMT is informing me that apparently some of the abellio 196s are having to be grounded for exactly the same fault.
Oh dear... let's hope this doesn't unfold into anything more serious. It's been a while since large numbers of a class have had to have been withdrawn for a problem, let alone a whole family of classes. TfW management will maybe be wearing brown trousers at the moment.
 

craigybagel

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Oh dear... let's hope this doesn't unfold into anything more serious. It's been a while since large numbers of a class have had to have been withdrawn for a problem, let alone a whole family of classes. TfW management will maybe be wearing brown trousers at the moment.
TfW are probably relieved that this has been discovered now rather then in a few years time when the units are in service to be fair.
 

southern442

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TfW are probably relieved that this has been discovered now rather then in a few years time when the units are in service to be fair.
That's true. Plus if there are a significant number that haven't been built yet then rectifying this potential problem would be very easy.
 

Irascible

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That's true. Plus if there are a significant number that haven't been built yet then rectifying this potential problem would be very easy.
That is assuming it's an easy rectification - if it turns out it's caused by something like part of the frame warping because it wasn't coping with the stresses invovled properly then that could be a literal rebuild. One would hope it's not anything that calamitous & maybe new dampers will solve it.
 

43096

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That is assuming it's an easy rectification - if it turns out it's caused by something like part of the frame warping because it wasn't coping with the stresses invovled properly then that could be a literal rebuild. One would hope it's not anything that calamitous & maybe new dampers will solve it.
From what has been reported so far, it’s not the damper that is the problem but the way it is attached to the body.
 

323 Class

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I clocked 331009 (14/04) at Dinting on the Man Picc-Glossop.
From the video still, you can see white marks on the soleplate where various structure is attached. Is this an indicator that examination has been carried out?
 

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Watershed

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I clocked 331009 (14/04) at Dinting on the Man Picc-Glossop.
From the video still, you can see white marks on the soleplate where various structure is attached. Is this an indicator that examination has been carried out?
Yes, I don't think it would be in service otherwise. Nice catch!
 

HSP 2

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Hopefully the fix could be as simple as welding a strengthening plate to the solebar where the yaw damper bracket is attached.
Does anyone know if the solebar that the damper bracket is attached to is steel of aluminium? As in the photo showing the bracket detached it looks quite thin say 1/4". If it is aluminium that is quite thin for a bracket that looks to be built to take a lot of stress.
 

edwin_m

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Little bit of a distraction perhaps, but my insider at WMT is informing me that apparently some of the abellio 196s are having to be grounded for exactly the same fault.
Is this that faults have been found, or just that they are stopping some for checks because they're the same design? If it's a fatigue fault it's only likely to develop after a certain amount of service, and Northern introduced theirs first.
 

AgentGemini

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I will need to confirm with my inside agent, but I get the impression that they had been found. However, again, do not quote until I confirm. :)
 

millemille

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Is this that faults have been found, or just that they are stopping some for checks because they're the same design? If it's a fatigue fault it's only likely to develop after a certain amount of service, and Northern introduced theirs first.
The rate of initiation and propagation will depend on relevant duty cycle so it is always uncertain when comparing across operators/routes until the exact contributory factors are understood.

Until the propagation rate of any crack is understood I'd presume that any crack detected, no matter how small - and I'd imagine inspection by now is beyond a simple visual examination and involves some form of NDT, may be dye penetrant - will result in that unit immediately being OOS.
 

Killingworth

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Northern Stakeholder briefing yesterday had this to say;

"Yaw Dampers: The last point this week you may have seen in the media. We have encountered some issues with our new electric (Class 331) and diesel (Class 195) vehicles. This was discovered at Easter where a fault was discovered in a yaw damper bracket. A yaw damper is a large shock absorber, which connects the movable bogie (ie the wheels) to the body. We immediately inspected the remainder of the fleet and 22 trains have been removed from the pattern. No faults found with the remainder of the fleet, but clearly this needs to be investigated which is underway with CAF the manufacturers. The 22 vehicles will not adversely affect the current timetable, and we are currently looking at the potential consequences for May. No issues yet, but we will keep you informed."
 

millemille

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an overly stiff damper could be the *cause* though ( along with a number of other things ).
For a damper to be that stiff, if that is the sole contributory factor to the vehicle body material failing, there would have been an affect on bogie steering which would have been evident in unusual wheel and track wear.

I notice from the photo's above that the ARB mounts on the sole bar are also being inspected.....
 

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