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P2 Locomotive Company and related matters

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

  1. The Green Howards

    The Green Howards Nat Pres stalwart

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    Aww, shucks.... looks like I'm going to end up being a covenantor to the P2 as well as Tornado now!
     
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  2. Eightpot

    Eightpot Resident of Nat Pres Friend

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    Are the cylinder bores smaller than the originals to reduce the overall width, or to spread out the piston rod centres a little?
     
  3. Foxhunter

    Foxhunter Member

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    With the increased boiler pressure (compared to the original class) the opportunity has been taken to fit smaller cylinders so that No. 2007 isn't as 'wide about the hips' as the early P2s - this means it will conform better with NR's loading gauge.

    Foxy
     
  4. Eightpot

    Eightpot Resident of Nat Pres Friend

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    Thanks for that info. 2001 was 8' - 11-1/4" over the cylinders, which is 1-3/8" more than an A3 at 8' - 9-7/8". However, with the P2 cylinders immediately in front of driving/coupled wheels rather than further forward between the sets of bogie wheels wouldn't the P2 have less 'throw-over' of the cylinders on curves compared with an A3?
     
  5. Foxhunter

    Foxhunter Member

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    ....meanwhile, in darkest Devon, the pace is being cranked up.... see the news here.

    [​IMG]

    Foxy
     
  6. Hermod

    Hermod Member

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    Last edited: Jun 8, 2017
  7. Matt37401

    Matt37401 Nat Pres stalwart

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    That looks a seriously big chunk of metal!
     
  8. Steve

    Steve Resident of Nat Pres Friend

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  9. S.A.C. Martin

    S.A.C. Martin Part of the furniture

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    Epic! Looks brilliant boys. Keep it up!
     
  10. Hermod

    Hermod Member

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    Was it some kind of poppet valve with rotary cams on P2?
    The forged ones can be stronger?P2s had crank issues.
     
  11. W.Williams

    W.Williams Well-Known Member

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    This was pressed? with heat right?

    Forging is great if you have the equipment, but a fabricated assy can be equally as well engineered.
     
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  12. Foxhunter

    Foxhunter Member

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    A critical failure area on the original class P2s was the crank axle. Modern principles are being adopted in the redesign of this critical area. Larger diameter components and the use of roller bearings are considered beneficial, and more modern techniques avoid stress points and relieve fatigue points. To this end the stubs are the largest that can be fitted with roller bearings and have stress relief grooves cut into them - clearly visible in the images.

    Foxy
     
  13. W.Williams

    W.Williams Well-Known Member

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    Have material grades helped too? Specifically that we have tougher grades nowadays.
     
  14. Eightpot

    Eightpot Resident of Nat Pres Friend

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    To answer your question 1) it is driven by a mini cranked axle on the middle (outside) set of driving wheels. Not by an eccentric.
     
  15. Hermod

    Hermod Member

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    Is it going to have roller inside conrod big end?
     
  16. LMS2968

    LMS2968 Part of the furniture

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    Not judging by the photo. The roller bearing has to be fitted before the second crank web; it cannot be fitted afterwards.
     
  17. 242A1

    242A1 Well-Known Member

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    Check out split roller bearings. I am not saying that fitting one would have been possible but they have existed for many years.
     
  18. Hermod

    Hermod Member

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    Yes, but the claimed beauty of built up cranks, is that it can be taken apart and assembled a couple of times.
    The picture shows not a pressing together opperation.
     
  19. LMS2968

    LMS2968 Part of the furniture

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    Yes, I know. But I have still to actually see one.
     
  20. LMS2968

    LMS2968 Part of the furniture

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    This is true, and must be done should the bearing need to be replaced. But it's a far from easy operation and one you don't do without good reason - or too often.
     

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