If you register, you can do a lot more. And become an active part of our growing community. You'll have access to hidden forums, and enjoy the ability of replying and starting conversations.

David Shepherd (RIP) and his locomotives.

Discussion in 'Steam Traction' started by Hicks19862, Sep 13, 2017.

  1. AndyY

    AndyY Member

    Joined:
    Feb 23, 2013
    Messages:
    433
    Likes Received:
    480
    Tom,
    Our posts crossed! But I'm glad to have someone agree.
    Andy
     
    Jamessquared likes this.
  2. LMS2968

    LMS2968 Part of the furniture

    Joined:
    Sep 1, 2006
    Messages:
    2,987
    Likes Received:
    5,084
    Gender:
    Male
    Occupation:
    Lecturer retired: Archivist of Stanier Mogul Fund
    Location:
    Wigan
    Heritage Railway Volunteer:
    Yes I am an active volunteer
    And the Tractive Effort being multiplied by the velocity (speed) is that being delivered to the rails, not the Nominal Tractive Effort, which has no place in any power calculation. And yes, no loco has yet claimed to beat LMS's 6234 power outputs of 26 February 1939.
     
  3. Big Al

    Big Al Nat Pres stalwart Staff Member Moderator

    Joined:
    May 30, 2009
    Messages:
    21,063
    Likes Received:
    20,773
    Location:
    1016
    Heritage Railway Volunteer:
    No I do not currently volunteer
    From what I remember, and I admit to not knowing the detail, I think that David's choice of locomotives was rather more prosaic. His love of elephants is well known and after the sell out success of his paintings in New York he returned to the UK determined to purchase something that captured the grandeur of these beasts in steam. In that context the choice of a snorting 9F was unsurprising and he also wanted to make certain that what he bought was in as near ex works condition as possible. At the time 92203 was only about eight years old and had recently been given an intermediate overhaul. I think that the Standard Class 4 was then bought, almost on a whim, but using the same criterion of something that was in good condition.
     
    oddsocks, LMS2968, Matt37401 and 3 others like this.
  4. Martin Perry

    Martin Perry Nat Pres stalwart Staff Member Moderator Friend

    Joined:
    Apr 15, 2006
    Messages:
    16,510
    Likes Received:
    7,753
    Location:
    1012 / 60158
    Heritage Railway Volunteer:
    Yes I am an active volunteer
    Well that's the last time that I try to be pointlessly flippant.

    (Just kidding :) )
     
    Jamessquared likes this.
  5. Steve

    Steve Resident of Nat Pres Friend

    Joined:
    Oct 7, 2006
    Messages:
    11,930
    Likes Received:
    10,088
    Occupation:
    Gentleman of leisure, nowadays
    Location:
    Near Leeds
    Heritage Railway Volunteer:
    Yes I am an active volunteer
    It also depends where you measure things; cylinders, rail or drawbar. All will give a different result. And, yes, I'm unaware of anything beating 6234. 3316 indicated (cylinder) horsepower from memory.
     
  6. Reading General

    Reading General Part of the furniture

    Joined:
    May 18, 2011
    Messages:
    6,081
    Likes Received:
    2,217
    it's ironic that so many locos bought privately were duplicated with locos from Barry later.
     
    Hicks19862 likes this.
  7. John Webb

    John Webb Member

    Joined:
    Mar 2, 2010
    Messages:
    501
    Likes Received:
    86
    Occupation:
    Retired
    Location:
    St Albans, Herts
    Heritage Railway Volunteer:
    Yes I am an active volunteer
    According to his autobiography "A Brush with Steam", he wanted a 75XXX because, as he says in the book: "I liked the sturdy and workmanlike appearance of the Standard Class 4s." 75029 was bought because friendly staff in the local sheds told him it was in good order.
    The 9F 92203 was recommended by other BR contacts when he said he wanted one of them.
    They were bought as part of a package deal by the Association of Railway Preservation Societies (now the Heritage Railway Association) negotiating with BR on behalf of David Shepherd and other groups and individuals; Clan Line, Blackmore Vale and others were involved.
     
    oddsocks, LMS2968, Hicks19862 and 2 others like this.
  8. andrewshimmin

    andrewshimmin Well-Known Member

    Joined:
    Mar 18, 2011
    Messages:
    1,761
    Likes Received:
    2,160
    Heritage Railway Volunteer:
    No I do not currently volunteer
    No British loco. Just for the avoidance of doubt....
     
    MellishR likes this.
  9. GWR Man.

    GWR Man. Well-Known Member

    Joined:
    Oct 8, 2014
    Messages:
    2,197
    Likes Received:
    2,413
    Gender:
    Male
    Location:
    Taunton
    Heritage Railway Volunteer:
    Yes I am an active volunteer
    In the ESR stock book Second Edition I have found the following information. The Standard Class 4 was withdrawn August 1967 for purchase and the 9F was withdrawn in November 1967 for purchase.
     
  10. Matt37401

    Matt37401 Nat Pres stalwart

    Joined:
    Jun 8, 2014
    Messages:
    15,326
    Likes Received:
    11,662
    Occupation:
    Nosy aren’t you?
    Location:
    Nowhere
    Heritage Railway Volunteer:
    No I do not currently volunteer
    And both have a little bit of interesting history, 75029 was the prototype for the testing of a double chimney on the WR, I believe Mr Ell was super confident about what he'd done (all but polished the tubes with Brasso!) and 92203 was part of the last through trains to Birkenhead, along with 4079 and 7029.
     
  11. Hirn

    Hirn Member

    Joined:
    Aug 11, 2015
    Messages:
    462
    Likes Received:
    295
    Gender:
    Male
    What tractive effort is useful for - and useful for in the rough an tumble of operating trains - is that it is
    a genuinely useful indication of wether a locomotive can a start a train. To coin a Chinese proverb: "No start, no run".

    Its other attraction is that it is readily demonstrably calculated, something you put in a specification and hold a
    contractor to account for. The fact that it is "at 85% boiler pressure" and that it is 85% and not 80% or 90%, however,
    should be an indication that it is an estimating tool - neither a scientific absolute nor a crude rule of thumb.
     
  12. Martin Perry

    Martin Perry Nat Pres stalwart Staff Member Moderator Friend

    Joined:
    Apr 15, 2006
    Messages:
    16,510
    Likes Received:
    7,753
    Location:
    1012 / 60158
    Heritage Railway Volunteer:
    Yes I am an active volunteer
    92203 also ran the last steam hauled Bidston to Shotton ore train I believe?
     
  13. johnofwessex

    johnofwessex Resident of Nat Pres

    Joined:
    Apr 6, 2015
    Messages:
    9,185
    Likes Received:
    7,226
    Gender:
    Male
    Occupation:
    Thorn in my managers side
    Location:
    72
    Heritage Railway Volunteer:
    No I do not currently volunteer
    I suggest that by 1967 it was as much as anything a question of what was avalible
     
    Hicks19862 likes this.
  14. Pete Thornhill

    Pete Thornhill Resident of Nat Pres Staff Member Administrator Moderator Friend

    Joined:
    Jul 24, 2008
    Messages:
    7,498
    Likes Received:
    5,455
    It did and was why it had an intermediate overhaul as I mentioned earlier in the thread.
     
    Hicks19862 likes this.
  15. BrightonBaltic

    BrightonBaltic Member

    Joined:
    May 26, 2011
    Messages:
    724
    Likes Received:
    242
    6234 managed 2,500dbhp - it is estimated that this equates to 3,333hp at the cylinders.

    I seem to recall reading that some Merchant Navies got pretty close, the only limitation being that, even with two firemen, Rugby never did find the upper limit of the MN's steaming capacity... it really needed the mechanical stoker fitted to CanPac (but removed at the rebuild).
     
  16. Steve

    Steve Resident of Nat Pres Friend

    Joined:
    Oct 7, 2006
    Messages:
    11,930
    Likes Received:
    10,088
    Occupation:
    Gentleman of leisure, nowadays
    Location:
    Near Leeds
    Heritage Railway Volunteer:
    Yes I am an active volunteer
    So, why does 85% boiler pressure come into it? And why did the Midland use 75%? And Hunslet, too.
     
  17. Matt37401

    Matt37401 Nat Pres stalwart

    Joined:
    Jun 8, 2014
    Messages:
    15,326
    Likes Received:
    11,662
    Occupation:
    Nosy aren’t you?
    Location:
    Nowhere
    Heritage Railway Volunteer:
    No I do not currently volunteer
    But at the time did anyone did anyone know about what would become of those machines dumped at Barry. If it wasn't for Dai we'd have only 2 each of 9F and 4MT.
     
    BrightonBaltic and Hicks19862 like this.
  18. MellishR

    MellishR Resident of Nat Pres Friend

    Joined:
    Apr 16, 2009
    Messages:
    8,068
    Likes Received:
    5,160
    Presumably it's a rough and ready average of the pressure in the cylinder during one whole stroke. At low speed the pressure would be close to 100% of the boiler pressure for part of the stroke, reducing after the valve closes to stop the admission of any more steam. That comes some time before the end of the stroke, depending on the cutoff setting, which is always well short of 100%.
     
  19. Jamessquared

    Jamessquared Nat Pres stalwart

    Joined:
    Mar 8, 2008
    Messages:
    26,099
    Likes Received:
    57,414
    Location:
    LBSC 215
    Heritage Railway Volunteer:
    Yes I am an active volunteer
    I came across a reference recently - I think it was in HAV Bulleid's "Master Builders of Steam" - that the choice of 85% was standardised on by the ARLE in the early years of the twentieth century, which I guess would be under the chairmanship of HA Ivatt. Standardisation allowed easier comparison of designs between companies, but as you say, it is a somewhat arbitrary figure: an estimating tool, as @Hirn suggests, not a precision characteristic. Also, as I understand, the ARLE was primarily a body of engineers for mainline companies, so the industrial builders were free to choose their own methodologies for calculation. I'm sure most literature I have seen on New Zealand locos (generally built abroad, often by British manufacturers) tends to assume a 75% figure.

    My reading of primary Victorian material is that TE is rarely explicitly mentioned, or appears on diagrams. Far more common that engines are described as something like "Mr Crankpin's new 18 inch goods locomotive" and it's capabilities would largely be inferred by reference to the fact that his previous locomotive was a 17.5" design; or maybe the new one has 150psi boiler and the previous design 140psi. Explicit calculations of TE don't seem very common, though obviously the concept was understood.

    Tom
     
  20. MellishR

    MellishR Resident of Nat Pres Friend

    Joined:
    Apr 16, 2009
    Messages:
    8,068
    Likes Received:
    5,160
    The P2 will have essentially the same boiler as Tornado, which can be expected to produce the same maximum amount of steam, perhaps slightly more or less according to how the different valves affect the draughting. Whether it will be more powerful depends whether its poppet valves can produce more efficient use of the steam than Tornado's piston valves. That was the justification for trying poppet valves on the original P2s (and various other locos) and is a reasonable aspiration, which does indeed remain to be proven in practice.

    As Tornado has the same size of grate as a Duchess and the same kind of valves one would expect their maximum power under ideal conditions to be about the same.

    Edit: not that this discussion has anything whatsoever to do with the official subject of this thread!
     

Share This Page