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P2 Locomotive Company and related matters

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

  1. class8mikado

    class8mikado Well-Known Member

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    Suspect that both in parallel will have been exploring the metallurgical possibilities available when (re)producing what are, by steam locomotive standards somewhat delicate components...
     
  2. 242A1

    242A1 Member

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    The steam locomotive standard is 40 hp per ton. Was established many years ago.
    And built to AAR standards with adequately designed facilities, that is to say fit for purpose unlike much of the steam service facilities provided in this country, playing the locomotive numbers game should present no problems. With more powerful locomotives capable of handling heavier trains you might well end up in the situation of needing fewer of them.
     
    Last edited: Jun 14, 2021
  3. Jamessquared

    Jamessquared Nat Pres stalwart

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    Which loco? You often seem to assert that number, but I don't recall seeing evidence, certainly not that it was a "standard".

    More importantly - what about the second part of @35B's question. Could 22 of these amazing locomotives do the same work as 22 Deltics? Because if not, you have to pro-rata the power per ton figure in proportion to the number of locos.

    Tom
     
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  4. 242A1

    242A1 Member

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    71000 has had valve issues to the extent that it confirms Porta's unwillingness to consider poppet types. What has been done with it is of little benefit to the P2 and when looked at it was impossible to use the BC gear on the engine. AT & SF locomotive 3752 is far more worth looking at and is covered extensively in Vernon L Smith's book, it wasn't perfect but set a worthy marker.
     
  5. Matt37401

    Matt37401 Part of the furniture

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    Are you serious? Ok how it’s a few years ago but how many P2’s made it to the likes of Oban, The Kyle and Fort Bill?
     
  6. Hermod

    Hermod Member

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  7. Jamessquared

    Jamessquared Nat Pres stalwart

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  8. Hermod

    Hermod Member

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    Exhaust steam injector?
     
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  9. 35B

    35B Nat Pres stalwart

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    For this innocent in advanced steam, some context would be helpful. My quest is because the Deltics represented a dramatic step change in the capability of motive power in this country, in terms of available power, and I am struggling to see where the step up that would have rendered them unnecessary was to have come from. That is before considering the ability of one locomotive to do the round trip from London to Edinburgh without darkening the doors of a shed, or needing the complexities of water cranes and troughs.


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  10. bluetrain

    bluetrain Member

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    When looking at a figure like that for comparing steam/diesel/electric traction, we need to establish whether it is inclusive or exclusive of the weight of fuel and water carried. I think the figure of 33hp/ton quoted for the Deltic was inclusive of the weight of its diesel fuel.
     
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  11. Jamessquared

    Jamessquared Nat Pres stalwart

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    Ah yes, possibly. (Just rationalising the mass-flow diagram in my head).

    Tom
     
  12. MellishR

    MellishR Part of the furniture Friend

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    I'm not sure whether you're comparing the original P2s with the Pacifics that existed at that time or the forthcoming P2 with (for example) Tornado. The latter two will have the same boiler, so will have the same amount of steam available. I would expect the Franklin valve gear to make slightly more efficient use of the steam than Walschaerts, though about the same as 71000's Caprotti gear. The P2 will presumably be able to exert more actual TE than the A1 before it slips.
     
  13. S.A.C. Martin

    S.A.C. Martin Part of the furniture

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    This simply isn’t true, born out by:

    • The detailed LNER archives at Kew
    • Records of the workings the locos did
    • Maintenance records in the form of the engine cards
    • Recorded workings of more reliable six coupled locos doing the same work more reliably in the form of the Gresley A4s, W1, Thompson A2/2 and Peppercorn A2
    I get that the P2s had the potential to be more potent than they were, but all of the six coupled big LNER locos outperformed them on a daily basis throughout their working lives. Let’s not kid ourselves here: as built, they were bettered by older Gresley designs and succeeded by better Thompson and Peppercorn ones.

    2007 may yet put right the issues of the original class, which is why I’m a founder member.
     
  14. Eightpot

    Eightpot Well-Known Member Friend

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    From memory the fuel tank capacity on a Deltic was 800 gallons. They would use about 600 gallons from London to Edinburgh and vice-versa, i.e., about 2/3 of a mile to a gallon.
     
  15. 242A1

    242A1 Member

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    What you refer to as amazing locomotives can be built and they have to be not only thermodynamically amazing but mechanically so too. But all this is worthless if the operating environment does not support such machines.

    It is said that the N & W dieselised without having to buy a diesel. How did this come about? The railway had its own workshops and design team and so built engines peculiarly suited to purpose. They included features not to be found on UK designs, particularly those built for the domestic market. The cast steel bed, self adjusting axlebox wedges, roller bearings are just some of the features. The railway also used special alloys in order to keep motion weight down. The J class had motion rods made of Timken high dynamic steel. The estimated weight for rods and valve gear was 10,725 lbs. The wartime production J1 class had rods and motion made of conventional carbon steel and these were calculated to weigh 17,558 lbs. The light weight set was also fitted with roller bearings but those that were more conventional were just that and the J1 suffered from bearing problems and in spite of much work resolving the issues these appear to have only been fully resolved when the J1s were converted to J type and lost the cost saving imposed limitations. This class of eleven engines represented 13.6% of the passenger locomotive fleet but could account for more than 50% of the passenger car mileage. Designed for purpose and capable of high utilisation. Features incorporated as a part of this thinking are included for a reason.

    Being capable of high utilisation as a design is one thing but achieving that utilisation is another and this comes down to the servicing facilities provided. A look at the facilities provided at Shaffers Crossing or Williamson shows what the railway provided to achieve what it undoubtedly did and if it was achieved there it could have been achieved and even surpassed elsewhere.

    A combination of superior locomotive designs combined with better support facilities does allow you to achieve more with fewer engines. What you can achieve depends on how much you try to improve and how well you can deliver. You can destroy the best machines in the world by subjecting them to woeful use and inadequate maintenance. and sadly this this happens.

    In all this much was achieved in other parts of the railway world but sadly not much had an impact on what we did here. You could say that reasons existed that prevented this which is all well and good but this does not take away regretting what might have been and perhaps what ought to have been.
     
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  16. 242A1

    242A1 Member

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    What were the load limits on the Aberdeen route for which they were designed? I know about the power output records of the Pacifics but for the route in question it was originally the need to dependably work trains of 530 tons which drove the design requirement. Adhesion and tractive effort were felt to be needed and in the end trains of 600 tons were handled. Though the maximum recorded horsepower we have available for the class is not particularly high it could be said that the design was a little unfortunate in that it preceded the A4 but there is little or no way that a locomotive of 11o.25 tons weight and 80.6 tons adhesive weight is not going to be at a certain advantage over a locomotive weighing 104.1 tons having a 66 ton adhesive weight when it comes to handling heavy trains over a difficult route.

    I have little doubt that the Trust has confirmed the issues known about at Doncaster and has made further progress in identifying and correcting issues that few, if any, suspected. I was impressed with the outcome of the Vampire computer modelling of the chassis behaviour and now await the results of the work being carried out by Frewer and Co.
     
    Last edited: Jun 15, 2021
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  17. MellishR

    MellishR Part of the furniture Friend

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    It seems well established that the original P2s had some real flaws, and possibly some other supposed but unconfirmed flaws (e.g. spreading the track). And Simon has established that they had poor availability. But when they were actually at work pulling trains on the Aberdeen road, did they pull them any better than the Pacifics, and if not why not?
     
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  18. Jamessquared

    Jamessquared Nat Pres stalwart

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    Indeed, that goes without saying - if you are comparing, you have to consider the weight with all supplies “ready to go”.

    Tom
     
  19. Jamessquared

    Jamessquared Nat Pres stalwart

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    So you still haven't answered the question - which standard loco was able to make 40hp / ton of all up weight, and could 22 of them have done the same work as 22 Deltics?

    Tom
     
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  20. 35B

    35B Nat Pres stalwart

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    That's fascinating and a very useful check on what happened here, but I did a quick check on the J and J1 class locomotives. Taking Wikipedia as my source, I get the following figures:
    * Locomotive weight - 224.1 tonnes
    * Tender weight - 171.7 tonnes
    * Total weight - 395.8 tonnes
    * Power output - 5,300hp

    That's phenomenal by any standard we're used to here, but it gives a power/weight ratio of 13.4hp/tonne for the locomotive. That compares with 3,300hp and 101 tonnes (if my conversion is right) for the Deltic, or a power/weight ratio of 32.6 hp/tonne - an order of magnitude different.
     
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