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Industrial Loco Updates

Discussion in 'Steam Traction' started by AlistairS, Apr 17, 2008.

  1. sleepermonster

    sleepermonster Member

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    Bagnall 2746 The Duke.

    The new shed floor has been concreted, which makes access to our own projects so much easier. The 8F diesel welder has been run up, so we now have our own welding capability. John has begun making good the seams in the footplate and bunker floor. GCR report that the new big end brasses have been fully machined and fitted and the connecting rods are ready to collect, hopefully the new bunker shell will be ready shortly also. Reassembly of the steam heat piping has begun. Russell Walker of RSR very kindly delivered a new safety valve casing and a raw casting for a main steam pipe elbow. The latter was not actually needed, but the price was very reasonable and you never know what you might need one day. Simon and Ian continue to work through the cab fittings.
     
  2. Cavickboy2

    Cavickboy2 New Member

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  3. sleepermonster

    sleepermonster Member

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    The first job last Saturday was to pick up a hire van and so escape from Multiple Mayhem at Wirksworth. To Loughborough to confer with David Wright at LMS, who showed us what at first appeared to be a large modern art coffee table. Actually it was our new copper tubeplate set up on trestles, which has been formed but needs dressing, smoothing and the holes drilling. The firebox backhead has been removed and the inner cracks are now revealed; we certainly took the right decision to go for a new one. The foundation ring was also badly cracked at the corners and would not have lasted much longer. One wonders how many older boilers have similar problems which have not yet been found; Dave's boiler examinations and NDT testing have been extremely thorough. At least the exposed plate on the firebox sides is extremely good, virtually as new.

    Then on to Loughborough GCR where we loaded the connecting rods and big ends, which now have new and beautifully machined bearings throughout.
    Back at base the rest of the team had been busy - the steam heat piping is nearer completion, with help from the LMSCA who loaned the use of their pipe threading machine. The combined steam brake valve is now complete and attention centres on the vacuum ejector - I am told this is just as worn. Never mind!
     
  4. estwdjhn

    estwdjhn New Member

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    IMHO Austerity backhead cracking is fundamentally the result of poor design which concentrates stress into the outside row of stays - I think every Austerity backhead I've ever seen the inside of has been cracked in the same places, the only thing that differs is the extent. I've seen some which had new inner fireboxes in their working lives, and have evidence of the backhead having been welded then (I.e. this implies they had already cracked). From what I've seen, I'm fairly convinced that Austerity backheads start to crack within a very short period from new, but the cracks only develop slowly, and in practice the backhead usually doesn't exhibit externally visible evidence of failure within the lifespan of the firebox.

    I'm fairly sure that most of the Austerities currently in steam have cracked backheads, but equally I'm also fairly sure that despite this, no undue risk is being posed.
     
  5. Steve

    Steve Resident of Nat Pres Friend

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    I've no experience of an Austerity backhead cracking through. Has anyone? It could simply be a situation of the crack propagates until the metal is thin enough to allow the necessary flexing. In other words, it is too rigid in its original design. I've experienced cracking on other bits of kit (not boilers) where they have been made of too thick a material, making them too rigid and, once thinner material was substituted, the problem went away.
     
  6. sleepermonster

    sleepermonster Member

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    In our case the cracking was both deep and extensive, only a few mm of thickness remaining. The cracks ran virtually from top to bottom of the backhead at either side, more than one column of stays being affected, plus between the holes at the clacks. So we had a choice - have the backhead taken off as carefully as possible in the hope that it would be repairable, potentially wasting a great deal of expensive time and/or committing to an expensive repair which might not last - or go for new, and we were given an excellent price for the new backhead. Once it was off...well at one point one of the cracks took the form of a triple crack between two stay holes.

    At least one earlier boiler inspection failed to spot the backhead cracks at all. The foundation ring cracks were a particular concern. I suspect that at some point in the past the boiler was particularly badly treated and we are seeing the results.
     
  7. Respite

    Respite Member

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    I know one of the drivers at Whitehaven told me of starting a shift where there was a bad blow from the LHS backhead of Repulse HE3698.
    He got the loco taken off work and the crack was veeed out and welded up. So far as I know it still has the weld on the backhead 43 years later.
     
  8. fergusmacg

    fergusmacg Well-Known Member

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    If my memory is correct that weld on Repulse was not between stays, but was on the radiused section of the back-head. The issue of cracking on the outer firebox of these boilers must be of interest to many within the preservation movement (given the no. of such locos in use), it could probably do with a little more of an airing to all railways that use these locos than can be given just from NP I would think, have you useable photos etc?
     
  9. Respite

    Respite Member

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    I think your memory could well be correct as it was certainly high up on the backhead.
    I recently viewed an austerity boiler that was only part way through its 10 year ticket, measurements on the backhead of 3.5mm around the foundation ring and lots of 5mm.
     
  10. estwdjhn

    estwdjhn New Member

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    It sounds like yours had a fairly advanced case of the disease. Interestingly, I think one of the worst I've seen was the backhead that had come out of Mountain Ash No8, which reputedly was lit up dry at Mountain Ash in an (unsuccessful!) attempt to write it off, which aligns with your suggestion that matters aren't helped by abuse of the locos (typically pushing them into steam too fast).
    I also find myself wondering if typical preservation use in many cases doesn't help matters, as it involves a lot more full boiler cycles from cold to hot and back for any given number of days steaming, but several Austerities that have hardly steamed in preservation have had the same issue.

    Is your throatplate alright? I've seen them crack up the outer row of stays in the same way as the backheads.

    Out of interest, how and where had the foundation ring cracked?

    IMHO that raises awkward questions about the competency or otherwise of it's boiler inspector who put that ticket on it.
     
  11. Respite

    Respite Member

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    It also raises questions about who repaired it.
    They had removed sections of the outer wrapper on the other side which should have aided internal inspection of the rest before replacing the cut out sections and also served as a warning about the rest!
     
  12. 32110

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    AB 1719 'Lady Nan'

    Now that Ivatt Cl. 2 Tank, 41313, is nearing completion, labour is becoming available to work on AB 1719. A small start on dismantling was made at the end of 2016. Today we had a team of three (difficult to get many more on such a small loco!) working on the loco. A good start was made stripping the manifold and its associated fittings and similar progress was made in the smokebox. Will post regular updates as things progress.
     
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  13. sleepermonster

    sleepermonster Member

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    Hi Estwjdhn, and others.

    I do have photos, but they are not mine to publish. There were 4 major vertical cracks, up the backhead shoulder on each side and up the outer column of stays on each side. One shoulder crack went continuously from the foundation into the start of the crown, the other was similar but with a short gap in the middle. The cracks between stays were around 40" long each. The backhead was also seriously grooved above the foundation ring and had saucer corrosion around the stay heads on the lower 4 rows. Firehole door rivets needed renewing and there were other defects, the lower part of the backhead needed to be renewed for reasons set out.....it could have been repaired- at a price, we preferred to renew the lot. The lower firebox sides are to be renewed for similar reasons, I'm glad to say the rest of the firebox and boiler plate seems to be pretty much as rolled.

    Throat plate: seriously cracked as Estwjdhn expected, cut out and already renewed with a new tombstone plate, i.e. the whole of the flat portion below and at the side of the barrel. We are having a new copper tube plate, so we can go back to minimum size stays. I may add that the speed and economy with which this was carried out encouraged our decision to renew the backhead.

    Foundation ring: severe cracks at the two rear corners. On one side , 3 vertical cracks, wide ones, at least half the width of the ring to the naked eye and leading down from the top of the ring centrally to the 3 corner rivets. On the other side 2 similar double cracks leading down tangentially to 2 corner rivets. If I recall correctly, there were some signs of cracking at the same rivets on the underside of the ring, but not as bad as that.

    Tim
     
  14. 32110

    32110 Member

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    AB 1719, 'Lady Nan'

    Now that 41313 is more or less complete we are starting to get on with AB 1719's 10 yearly. She has been transferred to the workshop and a good start has been made on getting her stripped down

    In workshop 7 Jun 17.jpg
     
  15. estwdjhn

    estwdjhn New Member

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    Both Wimblebury (Hunslet 3839 of 1956) and Eustace Forth (RSH 7063 of 1942) passed their in the frames boiler steam examinations on Friday, and have subsequently been out for loaded test runs up Foxfield bank. There still remains a bit of snagging work, and some cosmetic issues to deal with on both locos (the eagle eyed may notice Wimblebury is currently devoid of both cab windows and works-plates), but it definitely feels like we are getting there with them now.

    Unless unforeseen problems occur, both locos should be featuring (including loaded runs on the bank) during Foxfield's 3 day gala in just over a month (14-16 July).
    [​IMG]
     
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  16. sleepermonster

    sleepermonster Member

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    Bagnall 2746 The Duke

    Here is a technical question. We are rebuilding some of the cab fittings and need to obtain gunmetal bar for the purpose. There are two possibilities, LG4 and SAE660, the latter being much cheaper, probably because it contains less tin. Is SAE550 an effective substitute?

    Meanwhile back at Wirksworth, both connecting rods have been raised into place and the little ends assembled with the cross heads etc on the slide bars. The big ends have yet to be fitted.
     
  17. estwdjhn

    estwdjhn New Member

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    IMHO SAE660 is perfectly suitable for steam fittings - it's on the HRA's list of acceptable materials for washout plugs (from which one can reasonably infer it has suitable properties for things with steam pressure behind them!). LG4 is usually only available as cast, which I think is why it's so much dearer.
    To give a little background, traditionally washout plugs were cast from LG4, with just the thread machined on, now with the advent of modern CNC machining centres it's more effective to use SAE660 solid bar machined into plugs, and the use of these is now pretty wide-spread with no apparent ill effects.

    You do get the odd person who claims otherwise, and that SAE660 or BS1400 LG2 (both deemed acceptable by the HRA) shouldn't be used - in my experience, those claiming this are mainly people with patterns for casting washout plugs...!
     
  18. Steve

    Steve Resident of Nat Pres Friend

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    The ORR had a document " The management of steam locomotive boilers 2004" which had a section on materials for boilers. I'm fairly certain that this document gave wrought SAE660 as an alternative to LG4, which is a cast product. However, I've just tried to download it, only to discover that it has disappeared from the ORR website. I suspect that the reason for this is that the HRA have produced a large number of documents on boilers and, as these these are endorsed by the ORR, the ORR document is redundant. If you look at the HRA Guidance Note on Boiler Mountings and Fittings it lists SAE660 as a suitable alternative to LG4. There are other alternatives listed, as well.
    Edit. John beat me to it whilst I was typing away.
     
  19. sleepermonster

    sleepermonster Member

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    Many thanks; SAE660 ordered. Once again, Leeds Bronze gave the best price.
     
  20. pmh_74

    pmh_74 Active Member

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    HC1752 aka 0-6-0ST Austerity No.7 'Robert' and henceforth to be known as "68067" had a fire lit this week at the GCR. A photo was put on FB. I haven't seen any further info beyond that but it's obviously close to a return to action.
     

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