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Bluebell Motive Power

Discussion in 'Steam Traction' started by Orion, Nov 14, 2011.

  1. misspentyouth62

    misspentyouth62 Member

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    as far as I'm aware, new steel fireboxes have been contracted to SDR for 34039, 34101, 34059, 34023 and if my memory serves me, 34028 or 34016? The boiler for Bluebell's own 34059 has now been returned to SP with new firebox so looking forward to seeing this one re-entering the workshops soon.
     
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  2. Jamessquared

    Jamessquared Nat Pres stalwart

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    It’s already there - the chassis took the place of 80151 and the boiler has been in the workshop for some time.

    Tom
     
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  3. 5944

    5944 Well-Known Member

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    This was posted over on RMWeb last night. Maybe @Jamessquared has an idea?

    https://www.rmweb.co.uk/community/index.php?/topic/146587-bluebell-railway-o1-no-65/

     
  4. Jamessquared

    Jamessquared Nat Pres stalwart

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    A quick trawl of photos shows they were on all (or at least all I looked at) members of the class, and I’ve found one photo that seems to show them on pre-rebuild locos. I’d have to look at home for confirmation of that.

    I’ll see if I can find out why they are there, but given the position, my hunch is that it is related to access to the front of the valve spindles, possibly to allow a tool or rope to assist with withdrawing the valves for maintenance.

    Tom
     
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  5. 5944

    5944 Well-Known Member

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    Thanks Tom. I did wonder about that. Maybe setting up of the valves perhaps?
     
  6. Jamessquared

    Jamessquared Nat Pres stalwart

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    I don't think it is for valve setting; when you do that, the valve remains attached to the expansion link via the valve rod and the fine adjustment is made where the eccentric rods join the eccentrics. My gut feeling is that it is for when you need to remove the valves completely from the front of the valve chest.

    As for the comment about how prevalent it is - you wouldn't believe how frustrating it can be that Edwardian photographers liked side on shots! But from looking at quite a large number of locos of class O, hybrid Wainwright class O and O1, and "proper" Wainwright O1, I can only find two examples that didn't have the two holes.

    One of those is a 1902 view of class O No. 251, in which the front buffer beam is clearly still wooden.

    o-No.252-sladegreen-1902.png

    The other was the "hybrid" Wainwright class O1 No. 6 bought by the East Kent Railway as a class O No. 372 and partially rebuilt in 1932 by the Southern Railway. Interestingly, it looks like the buffer beam has been reinforced with a thin sheet of steel that may have covered the underlying holes.

    o1-ekr-No.6-sheperdswell-1939.png

    All the other photos I can find, which include examples of Stirling class O with steel buffer beams; one of the Wainwright rebuilds with high-pitched domeless boiler, and all the "pure" Wainwright O1s, appear to show the holes.

    o-No.A376.png


    o1-ekr-No.100-sheperdswell-1939.png

    So my working assumption is:

    - As built with wooden buffer beams, removing the buffer beam was not too difficult, and would have been done had access been needed to the valve spindles
    - When steel buffer beams replaced wood, the holes were drilled to facilitate access
    - They persisted through whatever variant of reboilering subsequently occurred
    - The East Kent Railway one was an exception in that respect, possibly on account of having a non-standard re-inforcement of the buffer beam added at some point.

    Tom
     
    Last edited: Aug 9, 2019
  7. Jamessquared

    Jamessquared Nat Pres stalwart

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  8. 60044

    60044 New Member

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    If the holes are there for a rope to pull the valves out they look to be very close together, closer than the spacing of the valve spindles. I would have thought an angled pull would be very much harder than the spacing of the valve spindles.
     
  9. Steve B

    Steve B Member

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    I think it possible that the valves are that close together - looking at the photos of the P Class cylinders above you can see how close those are (the lugs on the valve cover gives some idea), and yes I know a P is somewhat smaller than the O, but some things don't vary that much.

    Just a thought - I may be completely wrong!

    Steve
     
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  10. 60044

    60044 New Member

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    The C, I presume, has piston valves if they have to be pulled out for inspection, whereas I would guess that the P has slide valves, which can be closer together if they are mounted vertically - and I don't think that they could, or would need to be, pulled out for inspection!
     
  11. Jamessquared

    Jamessquared Nat Pres stalwart

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    Both the O1 and the C have slide valves, mounted vertically between the cylinders.

    A couple of photos from when the loco was being reassembled a few years ago. The first shows the back of the cylinder block with the glands for the valve spindles; you'll see how close they are together.

    IMG_2378.JPG

    The second shows the loco at from the front; the cover over the valve chest is obvious, and the two holes in the buffer beam can be seen to be at pretty much the same spacing as in the first photo.

    IMG_2484.JPG

    Tom
     
  12. 60044

    60044 New Member

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    OK, I admit I'm wrong! Still think it's unusual to extract the valve spindles from the front, though. I'm sure somebody will put me right on that as well, though!
     
  13. Steve B

    Steve B Member

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    I've lost count of the number of things that I've learned from Nat Pres, and a great side effect of this conversation has been the photos that Tom @Jamessquared has posted. I find those much more interesting than many of the "here's a train passing a field" photos - good though they can be!

    As for extracting valve spindles, I have no real idea about the whys and wherefores!

    Steve B
     
  14. fergusmacg

    fergusmacg Well-Known Member

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    Ive not really been following this thread so if this has been discussed before please ignore - but are these holes to allow the valve buckle tail rods to pass through the buffer beam to allow the buckle and the valve to be sufficiently forward enough so that the valve can be removed from the buckle for maintenance without removing the buffer beam?
     
  15. nine elms fan

    nine elms fan Member

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    Have to agree with what you say, also the number of likes he has received tells a story in its self.
     
  16. Maunsell man

    Maunsell man Member

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    Noted on the blog today an appeal has been started to fund the 9F overhaul. Remember watching this take its first ever run in preservation one midweek afternoon in 1990 when i had some annual leave to use up and was working on the Pillbox brakevan at HK. Be nice to see her up and running again
     
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  17. Jamessquared

    Jamessquared Nat Pres stalwart

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    From the e-newsletter:

    Show Me the Monel! No. 34059 "Sir Archibald Sinclair" Update

    Work on the firebox is progressing steadily, with the staying of the driver's side of the new firebox almost complete and excellent progress on the fireman's side and backhead.

    Steel stays have been used for much of the work, but with greater flexibility, monel metal stays will be used in areas where stress is found, such as corners, the combustion chamber, and the throat plate. The total number of stays needed is approximately 2,200, of which monel stays may account for 1,000.

    A standard 7/8 inch diameter, 6-inch length steel stay costs about £11, but monel metal stays are considerably more expensive at £45, and when the need arises, they are more difficult to remove. Monel is an alloy of between 52% and 65% nickel together with copper and smaller amounts of manganese, iron, carbon, and silicon. It is corrosive resistant and flexible but difficult to machine. Besides its use in railway fireboxes, it has wide use in aeronautical, marine, and petroleum industries where its corrosion resistance is important.

    Elsewhere, work on the chassis is continuing with the connecting and coupling rods having been removed from the outside motion, and work is underway to remove the motion to the inside cylinder. The cylinder cladding has been removed, cleaned, and painted, together with some of the brake rodding. Sections of the running plate also have been removed to give greater access to the chassis and the four Wakefield lubricators supplying oil to the cylinders and the slide bars.

    Coupled axleboxes and the inside valve spindle crosshead guides have been removed and the old oil drained. Copper pipework has been disconnected, then cleaned and carefully labelled. It will be checked and then annealed before it is reused.

    Over the next few weeks, the remaining items on the chassis will be dismantled so that it can be lifted off the wheels. This will allow inspection of the axle boxes, the crank axle, the front bogie, and trailing truck, as well as a thorough cleaning of the chassis before repainting.

    On the firebox, work will include the insertion of monel stays and the eventual knocking over of the stays to give a watertight seal between the stay the inner and outer boiler plates.

    By John Fry
    And as an addendum: There's a single line in the above "The cylinder cladding has been removed ...". I happened to do some of that with another colleague as a job to do in the last couple of hours of an "X" turn a month or two ago. That little phrase seems almost trivial; it is only when you look in real detail that you realise just how much work there is even in a simple, non-critical task like that. The cladding is made of at least a dozen different sheets on each cylinder, all made to fit, screwed into the underlying cylinder casting and with assembly or disassembly being in a specific order because of how bits fit over or under each other - take a close look next time you are up against a similar locomotive. And that's for something relatively trivial ... I mention it not because I consider it especially noteworthy or complex, but rather simply to show just how time consuming and laborious even as simple a task as "removing the cylinder cladding" actually is in practice.

    Tom
     
  18. Jamessquared

    Jamessquared Nat Pres stalwart

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  19. misspentyouth62

    misspentyouth62 Member

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    I must say that I relish your posts Tom.

    Steel stays have been used for much of the work, but with greater flexibility, monel metal stays will be used in areas where stress is found, such as corners, the combustion chamber, and the throat plate. The total number of stays needed is approximately 2,200, of which monel stays may account for 1,000.

    As an engineering novice so to speak, I've always been unclear how a firebox made of different metals can be held together with fixed stays that allow expansion and contraction without breakage? Metals with differing expansion coefficients would cause say a copper inner firebox to expand differently to an outer steel wrapper so why don't the stays break as a matter of course? First time I've heard of 'moral' so is this a modern solution to an age-old problem or was this this developed during steam days? Also, would copper stays only work if the inner firebox were Copper?
     
  20. 8126

    8126 Member

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    Monel was the wonder metal of the turn of the 20th century. It's a nickel-copper alloy, classically about 70:30, the composition of some Canadian deposits, but there's a whole family of them with subtle variations and additions. Compared to the sort of steels used in boilers, it's slightly stronger, but less stiff. It also has superb corrosion resistance. These are all good things for stays. On the downside, the raw material is expensive and it machines like you said something rude about its mother.

    The reason fireboxes work despite differential expansion is fundamentally that everything bends, preferably elastically. Stays therefore want to have as little lateral stiffness as possible, to minimise the stresses caused by the bending. A monel stay can be much thinner than a copper stay, because it's stronger, and also thinner than a steel stay, because corrosion is much less of an issue. Since bending stress for a given deflection is linearly proportional to diameter and the material's Youngs modulus (stiffness), you'll see that a monel stay has significant advantages where the inner and outer plates are likely to see large relative movements.
     
    Last edited: Nov 6, 2019

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