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LNER Q6 Cylinder Failure at Grosmont (NYMR)


OnTheBranchline

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It is a very odd failure mode.  The circumferential stress is usually twice the longitudinal stress and high stresses should have blown the cylinder apart like a burst gun barrel.  I suspect there is an unknown factor at work - corrosion or undiscovered casting defect.  Unfortunately I think it means a new cylinder block but can't be sure at this distance.  I don't really like metal-stitching (Metallock) on stressed parts - alright for holes in crankcases but not otherwise.

Petertfgf

 

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7 minutes ago, peterfgf said:

It is a very odd failure mode.  The circumferential stress is usually twice the longitudinal stress and high stresses should have blown the cylinder apart like a burst gun barrel.  I suspect there is an unknown factor at work - corrosion or undiscovered casting defect.  Unfortunately I think it means a new cylinder block but can't be sure at this distance.  I don't really like metal-stitching (Metallock) on stressed parts - alright for holes in crankcases but not otherwise.

Petertfgf

 

 

The right hand cylinder had a previously discovered crack which had been repaired.

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2 hours ago, Phil Bullock said:


Oh dear that’s a shame…. But best not to speculate, could be anything from relatively trivial to very serious.

Thtat's rather spectacular.  Definitely a clean underpants moment.

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8 minutes ago, Aire Head said:

 

The right hand cylinder had a previously discovered crack which had been repaired.

I had another look at the photos.  The crack surfaces look corroded so the crack could have been present for some time.

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A friend sent me the same pics from Facebook. My first comment was that's an old fracture as it isn't clean. He also mentioned it had been stitched.

It was lucky that it failed where it was on the crossing as you can see something flying out as the cylinder let goes. Well away from people. Glad no one was hurt.

 

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13 hours ago, rogerzilla said:

Is it cast in one piece with the smokebox saddle?  Looks too far gone for metal stitching.

 

A replacement cylinder was already in hand; drawings had been prepared and a pattern maker was being sought, the intention being to replace the cylinder during 2023/24 winter maintenance.

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That’s good to hear …. The issue was well understood then. At the end of steam a damaged cylinder would have meant a one way ticket to the scrapple…. Look at what the movement can do now, Bradley Manor a prime example.

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Announcement from the NELPG, copied from elsewhere: 

 

CLASS Q6 63395 – RH CYLINDER FAILURE 16.05.23

Class Q6 number 63395 suffered a failure of the right-hand cylinder yesterday while working a train out of Grosmont.

The failure is being investigated and it is too early to suggest the cause.

The locomotive had passed all routine examinations and has been working well in the early part of the NYMR season, having run over 2000 miles.

When we have more news we will let you know.

NELPG Board of Trustees

 

 

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The J27 had a replacement inside cylinder block made & fitted around 9 years ago, they know what they’re doing.

 

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Whilst jumping ahead of ones self, the old cracked block could make an interesting museum exhibit in its own right, has a story (and video) to tell and educational about maintenance, as well as how the the inside design of how a cylinder works.

I hope thye dont just toss it.

Edited by adb968008
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37 minutes ago, adb968008 said:

Whilst jumping ahead of ones self, the old cracked block could make an interesting museum exhibit in its own right, has a story (and video) to tell and educational about maintenance, as well as how the the inside design of how a cylinder works.

I hope thye dont just toss it.

 

A prime (ha ha - not that I am saying that is what happened) candidate for that is the block from Green Arrow. Construct a modern replacement using the same techniques that they used for the new build P2 and the old one would make a heck of an exhibit.

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The pattern for the J27 was made the old way, a work of craft by a young pattern maker, I saw it. 
Can now be done in CAD & 3D print. A disappearing art? You still need a foundry to pour the metal and machine shop to bore & finish it. 

 

Dava

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On 17/06/2023 at 07:40, Bucoops said:

 

A prime (ha ha - not that I am saying that is what happened) candidate for that is the block from Green Arrow. Construct a modern replacement using the same techniques that they used for the new build P2 and the old one would make a heck of an exhibit.

I would love to see Green Arrow running again also. Interesting comparison with Flying Scotsman and the A4s as some are still running...

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13 hours ago, chris p bacon said:

If only there was a Finney kit of one....😂

Yeah, must get back to that.... been a couple of years since I did too much on the pair of them! 

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