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Locomotive Boilers and Boiler Pressure

Discussion in 'Steam Traction' started by 30854, Oct 31, 2017.

  1. Hermod

    Hermod New Member

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    The Jubilee difference between Crewe and St Rollox with four figure accuracy makes it a bit suspicious.
     
  2. S.A.C. Martin

    S.A.C. Martin Well-Known Member

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    So hang on - Thompson's A2/2s were near as makes no difference as economic to run as the Peppercorn A1 and A2 on boiler repairs, the Thompson A2/1 was cheaper on boiler repairs than the V2 which shared...the exact same type of boiler...

    Astonishingly low figures for the Bulleid machines - or is that actually not a surprise? They used more extensive water softening equipment on the Southern Railway than the other railways, no?

    The difference between the cost of a B1 and an O1 despite having the same boiler type is another oddity.
     
  3. Eightpot

    Eightpot Part of the furniture

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    Even A. F. Cook noted - "Finally it must be said that some of the anomalies are so great as to cast some doubt on the accuracy of the figures, even though BR had presented them to four significant figures."

    Why, for example, are the repair costs for a 'Jubilee' (3A) boiler at Crewe less than 2/3 of those for the same type boiler repaired at St. Rollox, yet 5MT (3B) boiler costs were almost equal at the same two works? As to how an A3 boiler repair was only 3/4 that of a V2 one (which was only an A3 boiler with a 2' shorter barrel) must now remain a complete mystery! Also of note is that the cheapest LNER Pacific boiler repair cost of an A4 was even better (less) than the Peppercorn A1 and A2 . Indeed it would appear strange that these 250 psi boilers were cheaper to repair than the 220 psi ones which rather upset the notion held that the the higher the pressure, the more the cost.
     
    Last edited: Nov 2, 2017
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  4. 35B

    35B Part of the furniture

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    It would be interesting to know how the figures were compiled. I suspect the role of averages, with distortions due to very high or low numbers of locomotives worked on.


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  5. Jimc

    Jimc Well-Known Member

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    The water in use for each boiler type would doubtless be significant too.
     
  6. 8126

    8126 Member

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    Apart from being (pleasantly) surprised by how far ahead of the pack the Bulleid boilers seem to have been, I don't find any of this massively contentious. Regarding the B1/O1 difference, remember these are costs per mile. For a given day's work, I would expect a B1 to go further than an O1, but in terms of thermal cycles and even coal burnt in the boiler, there probably isn't much in it. The same applies again when considering express passenger locos compared to mixed traffic. So, the B1 and Black 5 certainly should come out cheaper than the O1 and 8F.

    Local discrepancies can also distort figures quite strongly for small classes, so if all of the A2/2s were in an area with good water you'd expect them to come out better than the V2s, which went everywhere on the LNER that could take the weight.

    The significant discrepancy in Jubilee costs between works is interesting, but I wonder if the operating environment may have had a bit to do with that - or St Rollox simply didn't do many Jubilees and lost out on economies of scale that they did get with the Black 5s, where they compared well to Crewe.

    Swindon looks expensive, not only in the Halls and 28XXs but also the Castles compared to the Lord Nelsons. Remember that the Lord Nelsons were a small fleet, probably on average the oldest in the table without significant reconstruction (maybe the 28XXs considering the age of the early ones), and were known for needing a bit of care and attention from boilersmiths, but the massive fleet of similar sized Castles on similar duties turn out more expensive. (Edit to add: the Lord Nelson boiler design is pure GWR practice implemented by Eastleigh, so quite comparable to a Castle boiler.)

    Finally, I can see why the Counties had the boiler pressure reduced, but I'm not sure the Bulleids needed it (started that year).
     
    Last edited: Nov 2, 2017
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  7. andrewshimmin

    andrewshimmin Active Member

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    I wonder why the Duchess repair is shown as so expensive?
    Although the great availability of the LMS type meant 7 Duchesses did the work of 8 A4s, for example (64000 as opposed to 56000 miles per year in revenue service). I wonder what the comparison with Bulleid Pacifics would be?
     
  8. sir gilbert claughton

    sir gilbert claughton New Member

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    possibly economy of scale . 38 locos , 2 years between general repairs would suggest one Coro in the works at any given time .

    Doncaster would have had probably at least 6 Pacifics to work on which should have been more efficient .

    the type of work they were used on would also have had a bearing on repair cost , and I suspect the Stanier locos were repaired to a higher standard
     
  9. Cartman

    Cartman Member

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    Doncaster Pacifics didn't have to haul 14 up Shap or Beattock. The East Coast mainline was much easier graded. Could that have had a bearing?
     
  10. S.A.C. Martin

    S.A.C. Martin Well-Known Member

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    Possibly. The complexities of the duchess boiler in manufacturing against the A4's is potentially a factor too.
     
  11. andrewshimmin

    andrewshimmin Active Member

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    But (as I posted earlier this week elsewhere) the LMS found Swindon-descended boilers cheaper to maintain than round-topped or belpaire parallel ones. That's why they kept building them, even though they cost more and (as the early days of the Jubilee will tell you) didn't always steam as well. Or so I read somewhere.
     
  12. fergusmacg

    fergusmacg Well-Known Member

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    Yer - but the steaming troubles of the Jubilees had little to do with the type of firebox (round or belpaire) but was in the 'tube' department.
     
  13. Eightpot

    Eightpot Part of the furniture

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    True, but their steaming/draughting shortcomings were never really solved on the class as a whole.
     
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  14. 30854

    30854 Well-Known Member

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    This becomes more interesting by the post. Assuming BR(M) workshops to be better attuned to handling Belpaire boilers than (pick a BR(E) workshop) .... Donny, tooling and familiarity surely had a knock-on effect on costings?

    Perhaps figures (by works) for Belpaire boilered N7/1/2 and round topped N7/3/4/5 locos may provide a more illuminating comparison?
     
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  15. fergusmacg

    fergusmacg Well-Known Member

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    The trouble with all this is to try and isolate the true cause of increased costs, take a comparison of a Swindon hall boiler and one one on a black 5, on the surface they are broadly similar however deep down there are a number of differences in design but also such things as sheet steel thickness and for example the use of more nickel in the steel of LMS boilers (to reduce thickness - but is more prone to cracking) are a factor. The only proper analysis can be made on identical boilers working on the same type of services and using the same type of water/coal/mileage etc., any other comparisons can only scratch the surface of the true reasons for those increased costs.
     
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  16. sir gilbert claughton

    sir gilbert claughton New Member

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    plenty of evidence for heavier loads than that . the overnight Postal would load 18/19 -650 tons + . unassisted .
    5A had a special link for these very heavy overnight jobs .

    I saw "19 on" many times thro Harrow in the '50s. cant remember 20 tho'. the Scots would often take 17
     
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  17. Steve

    Steve Resident of Nat Pres Friend

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    There's a saying that, if you can't measure it, you can't manage it. However, having the measure is not the end result. You have to be able to understand and interpret the measurements having regard to a host of other related criteria. This is where people often fall down, especially the bean counters who usually look at such things in isolation. It's no use imposing the cheap to repair boiler if it won't do the job. The Duchess may cost three times that of an A4 and most people see them as the ultimate company rivals but they were built to do rather different jobs. The A4 was designed for high speed light trains whilst the Duchess was designed for pure hard slogging up steep gradients with heavy trains. Swap the two to opposite sides of the country and I bet the operating authorities would not have been happy chappies.
     
  18. 1472

    1472 Active Member

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    I suspect that too much is being read into this table which clearly states that it relates only to 1954.
    For example at that date the WC/BOB & MN locos were still fairly new compared to some of the types they are compared with and its therefore pretty unsurprising that their boiler repair costs were lower per mile ran.
    To make any real sense costs would need to be compared over a long period.
     
  19. 8126

    8126 Member

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    I thought that too to begin with, but look at the LNER A1s for comparison, all built post-nationalisation, unlike a good half or more of the Bulleids.
     

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