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P2 Locomotive Company and related matters

Discussion in 'Steam Traction' started by class8mikado, Sep 13, 2013.

  1. Bikermike

    Bikermike Well-Known Member

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    But you know the answer to that already
     
  2. 242A1

    242A1 Well-Known Member

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    It is quite hard to avoid the impression that some whose loyalties and affections lie with other companies and regions are wishing that this project had never started. 43,684 lbs tractive force, 80 tons adhesive weight and 3,400 hp are all probably good reasons why. There are going to be some grapes and they will undoubtedly be sour to some.
     
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  3. The Green Howards

    The Green Howards Nat Pres stalwart

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    I recall Mark Allatt saying at one of the roadshows "despite what fans of certain red engines say, this will be the most powerful steam locomotive in the UK - right, David [Elliott]?"
     
  4. LMS2968

    LMS2968 Part of the furniture

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    Wrong, and if he wants to prove it is, he will need to produce the documented evidence obtained by scientific apparatus, which is not a stopwatch.

    The reality is that there are a lot of claims for higher power outputs then those in pre-Nationalisation and BR days obtained in preservation, including some by a couple of big red engines, but there is no real evidence scientifically obtained to support them. Train weight, stop watch figures and train resistance formulae just don't cut the mustard.
     
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  5. Cartman

    Cartman Well-Known Member

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    Duchess of Abercorn?
     
  6. 30854

    30854 Resident of Nat Pres

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    U1?
     
  7. LMS2968

    LMS2968 Part of the furniture

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    Yes, and even that is slightly spurious. Realistically, to measure a steam loco's power output, you do it with an indicator diagram. This wasn't done with 6234 but it was claimed entirely from data from the dynamometer car. This measures the drawbar pull (the tractive effort or force being delivered to the train after that needed to move the loco has been used and subtracted), integrates this Actual Traffic Effort with the speed at that time (Power = Force x Velocity or Torque x Angular Velocity [call it r.p.m.]) to produce the d.b.h.p. (Drawbar Horsepower), adds a (pretty accurate) calculated value to take into account that the train is going uphill so more of the horsepower is being used to move the loco against gravity to produce the e.d.b.h.p. (Equivalent Drawbar Horse Power). These values were 2511 hp and 2870hp respectively. They them added a conversion formula to obtain an approximation of the Indicated Horse Power (i.h.p.) being produced in the cylinders and this came out at 3348 hp (sometimes wrongly given as 3248 with 3333 at a different location). Some of this power is used to overcome the loco's resistance over the track and its own internal resistance, e.g. bearings and pistons moving within the cylinders. The record is claimed on the measured d.b.h.p. figure although the i.h.p. figure (higher than a Deltic or Class 86) commonly arises, but the d.b.h.p. figure is accurate and verifiable. Claims in preservation depend on speeds, train weights and resistance formulae, all imprecise but extrapolated to give a fictional i.h.p. figure.

    I can accept that 6234's power output might have been exceeded in preservation, and probably has been, but putting a number to it is at best an educated guess.
     
    Last edited: Nov 27, 2022
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  8. LMS2968

    LMS2968 Part of the furniture

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    No, but this engine explains why Tractive Effort, especially Nominal Tractive Effort from an Ian Allan ABC, cannot be used as a measure of power output. Let me present a fictional scenario.

    The U1, with a Nominal Tractive Effort of 72940lb, has been on public display at Kings Cross. The driver preparing the A4 to work the Down 'Elizabethan' tells the running foreman the neither injector will work so he is failing the engine. The foreman says, "Don't worry, the U1's in steam. That's got twice the tractive effort of an A4. That will easily keep time!"

    Just imagine the driver's comment.
     
    Last edited: Nov 26, 2022
  9. Big Al

    Big Al Nat Pres stalwart Staff Member Moderator

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    Moderator Note

    A reminder. This is the P2 thread. Please keep the discussion on topic.
     
  10. D1002

    D1002 Resident of Nat Pres

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    A sight I would love to see (from Twitter):
    4FFCF122-8DE5-4B12-9606-5AB6D8E67FEB.png
     
    Last edited: Nov 29, 2022
  11. The Green Howards

    The Green Howards Nat Pres stalwart

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    Last edited: Nov 29, 2022
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  12. D1002

    D1002 Resident of Nat Pres

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    It is by Chris Ludlow. You can just about make out his signature in the lower left hand corner.
     
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  13. Foxhunter

    Foxhunter Member

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    I have to confess that NatPres is littered with examples of "glass half empty" comments by negative nay-sayers who will never have a good word to say about ANY project, their contributions must be incredibly disheartening to many of those who literally dedicate their lives to some of these projects. Just sayin'.......

    Foxy
     
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  14. 240P15

    240P15 Well-Known Member

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    Very well said Foxhunter!:)
     
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  15. class8mikado

    class8mikado Part of the furniture

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    But at what speed... ?
     
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  16. The Green Howards

    The Green Howards Nat Pres stalwart

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    "Locomotive performance" thread just over there...
     
  17. S.A.C. Martin

    S.A.C. Martin Part of the furniture

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    Locomotives of 6ft 2in wheel diameter or above are cleared for up to 75mph running.

    Since the P2 has 6ft 2in wheels, it is likely that will be the accepted stipulated maximum.
     
  18. class8mikado

    class8mikado Part of the furniture

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    Thanks Simon.
    Rephrase the question -at what speed ? will the P2 be Britains most powerful steam loco...
     
  19. 30854

    30854 Resident of Nat Pres

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    I take it the beastie does feature electric headcode lamps, which I seem to recall being a condition of 75mph mainlining?
     
  20. class8mikado

    class8mikado Part of the furniture

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    Probably got real time configurable Led Arrays that can tell you what its next stop is and remind you to take all your belongings with you...
     
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