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Northern withdraws some CAF trains due to yaw bracket failures

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hwl

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Wonder whether all this comes from the modifications to the coupling boxes. They where modified as there where not of enough size to accommodate the movement of the inner vehicle couplers around tight track as i understand.

If this was the case then the bogies may be moving a lot more and possibly outside the envelope envisaged originally by the designers of the yaw damper bracket and when the mod for the coupler box was done no thought was given to what else may be struggling with tight curves. Just a thought, not an engineer or rolling stock technician.

You aren't the only one to be thinking that. The dampers are also optimised for a small range of movement at higher speeds so large range movements at low speed (i.e. tight curvatures) may cause a few issues.
 
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Xenophon PCDGS

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You aren't the only one to be thinking that. The dampers are also optimised for a small range of movement at higher speeds so large range movements at low speed (i.e. tight curvatures) may cause a few issues.
Should that not have been a matter in the early discussion stages that led to the specification for these units being drawn up and finalised?
 

hwl

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Should that not have been a matter in the early discussion stages that led to the specification for these units being drawn up and finalised?
They forgot to specify compliance with infrastructure to GB group standards and not the European interoperability ones. Track geometry in some sidings and turnback locations is more extreme in the GB curvature.

I have suspicion that large rotations with movement near the end of ranges might prove quite interesting.

Dampers can do interesting things near the end of their movement ranges...
 

Xenophon PCDGS

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I had a visit to my consultant earlier today at his Wigan suite, so decided to travel on the 1128 Northern Manchester Airport service to Barrow-in-Furness, which has only a few stops before reaching Wigan North Western station. It was a Class 195 (forgot to jot down the number) and it was a problem free ride there, though knowing of the yaw damper problems, I was a little worried.
 

AlexNL

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I wouldn't worry about it, the problem is known and the units which are still in service get inspected regularly. If an issue is found on a specific unit, it will be withdrawn from service well before the issue develops into a problem.
 

northernchris

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Have any of the affected units returned to service yet? Seen a couple of 195s this week for the first time in a few weeks so not sure if it's just coincidence
 

skyhigh

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I had a visit to my consultant earlier today at his Wigan suite, so decided to travel on the 1128 Northern Manchester Airport service to Barrow-in-Furness, which has only a few stops before reaching Wigan North Western station. It was a Class 195 (forgot to jot down the number) and it was a problem free ride there, though knowing of the yaw damper problems, I was a little worried.
There's honestly nothing at all to worry about as a passenger. Testing (beyond just visual inspection) is ongoing any if there's any chance of issues the unit will be stopped.
Have any of the affected units returned to service yet? Seen a couple of 195s this week for the first time in a few weeks so not sure if it's just coincidence
No, still the same 22 units stopped.
 

AWCook

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Can anyone share where the out-of-service units are stored? Allerton and Newton Heath? Is there a list?
 

Adam0984

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Theyre all over the place. Allerton, Blackpool, Newton Heath, Huddersfield, Barrow
 

HSP 2

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Hello all,
yaw bracket failures I don't think that after seeing the second photo that's going to be an easy fix. I think that most of have seen this photo.

image.png.3bd26db95b7596d7f6782bb160c38abd.png But I came across this photo on a website showing the damage that is done to the mounting channels under the body. This looks like that the four tee nut in the channel are just not spreading the load enough. If you notice it's the two outermost nuts that have failed and ripped the aluminium channel. image.png.e310651e05d66eaa6d36522163842c61 - Copy.png

When you look at the front mounting point for the bracket you can see how much this bracket has bit into the channel section, so how long had it gone on before the failure?
What to do to fix it? I've put my old engineering hat on and thought of some, but I'd like to hear what people on here say. I'll give you one to start with a packing piece between the bracket and the channel sections, down side is that would use the same tee nuts but would spread the load.
 

DustyBin

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Hello all,
yaw bracket failures I don't think that after seeing the second photo that's going to be an easy fix. I think that most of have seen this photo.

View attachment 95947 But I came across this photo on a website showing the damage that is done to the mounting channels under the body. This looks like that the four tee nut in the channel are just not spreading the load enough. If you notice it's the two outermost nuts that have failed and ripped the aluminium channel. View attachment 95948

When you look at the front mounting point for the bracket you can see how much this bracket has bit into the channel section, so how long had it gone on before the failure?
What to do to fix it? I've put my old engineering hat on and thought of some, but I'd like to hear what people on here say. I'll give you one to start with a packing piece between the bracket and the channel sections, down side is that would use the same tee nuts but would spread the load.

Interesting photographs, I hadn’t seen the second one so thanks.

I may be misunderstanding your proposed solution but I’m not sure how a packer between the bracket and channel would work. Surely to spread the load effectively it would need to be inside the channel? Instead of individual nuts (or are they actually washers, it’s hard to tell?) they could try a continuous length of bar with the holes in the correct position. It would need to be rigid enough to prevent the forces being transferred in the same way though.
 

HSP 2

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I should have said the packer would have to be welded to the channel sections and be longer than the brackets, getting the tee nuts in the right place could be fun though. I did think about what you mentioned in your reply about a full length tee nut with the taped holes at the correct centres to the bracket would also work as long as they were longer than the bracket, it could be a bit of a job getting them in the channel though.
Or the other option would be to make a new yaw damper bracket that's longer and incorporates the lifting bracket as well.
 

edwin_m

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Interesting photographs, I hadn’t seen the second one so thanks.

I may be misunderstanding your proposed solution but I’m not sure how a packer between the bracket and channel would work. Surely to spread the load effectively it would need to be inside the channel? Instead of individual nuts (or are they actually washers, it’s hard to tell?) they could try a continuous length of bar with the holes in the correct position. It would need to be rigid enough to prevent the forces being transferred in the same way though.
That sounds like a good solution - might even be achievable without filling the gaps in the aluminum, by spreading the load across the intact parts of the channel. If the bar isn't rigid enough then maybe put some more holes in it and replace the bracket by one with extra bolts in corresponding positions.
 

Lewis Tickle

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Hello all,
yaw bracket failures I don't think that after seeing the second photo that's going to be an easy fix. I think that most of have seen this photo.

View attachment 95947 But I came across this photo on a website showing the damage that is done to the mounting channels under the body. This looks like that the four tee nut in the channel are just not spreading the load enough. If you notice it's the two outermost nuts that have failed and ripped the aluminium channel. View attachment 95948

When you look at the front mounting point for the bracket you can see how much this bracket has bit into the channel section, so how long had it gone on before the failure?
What to do to fix it? I've put my old engineering hat on and thought of some, but I'd like to hear what people on here say. I'll give you one to start with a packing piece between the bracket and the channel sections, down side is that would use the same tee nuts but would spread the load.
Looks like the Newton Heath staff will have to get their masking tape out XD
 

Beatbox00

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I should have said the packer would have to be welded to the channel sections and be longer than the brackets, getting the tee nuts in the right place could be fun though. I did think about what you mentioned in your reply about a full length tee nut with the taped holes at the correct centres to the bracket would also work as long as they were longer than the bracket, it could be a bit of a job getting them in the channel though.
Or the other option would be to make a new yaw damper bracket that's longer and incorporates the lifting bracket as well.
solution trials ongoing.....
 

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Jamesrob637

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I've heard that 24 331s are out of service. But maybe not all at the same time. Is this true? Source below:


ALMOST a quarter of the new model of train introduced by Northern Rail in the past two years have been removed from service due to a fault.

And this fault will lead to some services in West Yorkshire later this month being disrupted.

24 trains from Northern Rail's new electric (Class 331) and diesel (Class 195) fleets were recently withdrawn after being found to have a problem with a shock absorber designed to prevent swaying in the carriages.
 

175001

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As posted on this very forum, it's a mix of both 331s and 195s.

195002 is running ECS across the North West at the moment with measurement equipment attached to the yaw dampers to learn more about the fault.
 

skyhigh

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What is the state of play time-wise when the first repairs to the Class 195 and Class 331 units will commence and will one particular facility handle the repairs.
Still no idea. There's currently a temporary fix being worked on, but modifications to remove the issue are still under discussion (you can still see the crack in the photo of the trial unit). Deciding upon locations to repair the units is still way off yet.
 

northernchris

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Just seen 195013+195025 heading through Leeds towards Neville Hill, these were 2 that were stored at Huddersfield sidings. Could this be a sign of their return to service?
 

alm37

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Just seen 195013+195025 heading through Leeds towards Neville Hill, these were 2 that were stored at Huddersfield sidings. Could this be a sign of their return to service?
331022 and 331031, which had both been out of service since the yaw damper problem was first reported, are both back in service this morning. Is the temporary fix starting to be applied?
 
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