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.

V4 2-6-2 No. 3403

Discussion in 'Steam Traction' started by Foxhunter, Jan 30, 2018.

  1. LesterBrown

    LesterBrown Member

    Joined:
    Jan 20, 2009
    Messages:
    920
    Likes Received:
    678
    Location:
    Devon
    Is this leading towards "British Exit" as a name?
     
  2. Jamessquared

    Jamessquared Nat Pres stalwart

    Joined:
    Mar 8, 2008
    Messages:
    17,945
    Likes Received:
    29,068
    Location:
    21C102
    Quite apposite, given the general chicken-related naming theme seen thus far!

    Tom
     
    S.A.C. Martin, 5944 and Allegheny like this.
  3. 5944

    5944 Well-Known Member

    Joined:
    Jan 14, 2006
    Messages:
    5,280
    Likes Received:
    2,267
    Gender:
    Male
    Occupation:
    Train Maintainer for GTR at Hornsey
    Location:
    Letchworth
    Heritage Railway Volunteer:
    No I do not currently volunteer
    [​IMG]
     
  4. The Green Howards

    The Green Howards Part of the furniture Friend

    Joined:
    Feb 20, 2016
    Messages:
    9,021
    Likes Received:
    4,247
    Occupation:
    Layabout
    Location:
    Your nightmares
    Heritage Railway Volunteer:
    No I do not currently volunteer
    After the bill I've just had for the car, that's entirely appropriate... :Bawling:
     
  5. class8mikado

    class8mikado Member

    Joined:
    Jun 1, 2009
    Messages:
    2,847
    Likes Received:
    921
    Occupation:
    Print Estimator/ Repository of Useless Informatio.
    Location:
    Bingley W.Yorks.
    Heritage Railway Volunteer:
    No I do not currently volunteer
    Perhaps Pegasus could lead to a 'My Little Pony ' Tie in with some Rainbow smoke generators and strategically placed sparkly stars...
     
  6. flying scotsman123

    flying scotsman123 Resident of Nat Pres

    Joined:
    Sep 9, 2013
    Messages:
    7,610
    Likes Received:
    10,228
    Gender:
    Male
    Location:
    Cheltenham
    Heritage Railway Volunteer:
    Yes I am an active volunteer
    :Vomit: :Vomit: :Vomit:
     
    60017 likes this.
  7. 60017

    60017 Part of the furniture Friend

    Joined:
    Jul 6, 2008
    Messages:
    7,824
    Likes Received:
    5,236
    Gender:
    Male
    Occupation:
    Retired from corporate slavery :o)
    Location:
    Fylde Coast
    Heritage Railway Volunteer:
    No I do not currently volunteer
    ...and the Queen blinks at the light!
     
  8. 240P15

    240P15 Well-Known Member

    Joined:
    Dec 1, 2017
    Messages:
    1,188
    Likes Received:
    1,046
    Gender:
    Male
    Location:
    Norway
    Heritage Railway Volunteer:
    No I do not currently volunteer

    The sadly lost "Silver Link" would be an interesting candidate.:)
     
    Spamcan81 likes this.
  9. Spamcan81

    Spamcan81 Nat Pres stalwart

    Joined:
    Aug 25, 2007
    Messages:
    30,140
    Likes Received:
    14,103
    Occupation:
    Training moles
    Location:
    The back of beyond
    Heritage Railway Volunteer:
    Yes I am an active volunteer
    My favourite A4, especially in its “silver” livery.
     
    240P15 likes this.
  10. 242A1

    242A1 Member

    Joined:
    Dec 3, 2006
    Messages:
    1,173
    Likes Received:
    645
    Not quite what I had in mind. There was a version of the A4 that was close to being authored prior to WW2 which was to have a boiler pressure of 275psi. Not quite the 20bar/300psi to be found elsewhere but getting there you might say.
     
    stephenvane likes this.
  11. class8mikado

    class8mikado Member

    Joined:
    Jun 1, 2009
    Messages:
    2,847
    Likes Received:
    921
    Occupation:
    Print Estimator/ Repository of Useless Informatio.
    Location:
    Bingley W.Yorks.
    Heritage Railway Volunteer:
    No I do not currently volunteer
    But almost the 280 found elsewhere...
     
  12. Jamessquared

    Jamessquared Nat Pres stalwart

    Joined:
    Mar 8, 2008
    Messages:
    17,945
    Likes Received:
    29,068
    Location:
    21C102
    I think it is easy to fetishise the pressure number without thinking it through. Higher pressure theoretically gives more TE, but only if you can use it - a factor that was realised when the Bulleid pacifics were downgraded to 250psi, after it was noted that drivers rarely used above about 200psi on the steam chest gauge. The thermodynamic benefit of higher pressure is fairly small when seen in terms of the overall thermodynamic efficiency of the loco. On the other other hand, boiler construction and maintenance costs go up. Its notable in this country that AFAIK, all the main locos built with conventional, but high pressure, boilers (i.e. > 250psi) were subsequently modified to reduce the working pressure.

    Engineering isn't about a top trumps style quest for the biggest number: it is about making rational compromises of competing factors to come up with the best overall design. In that light, generally maintenance costs proved more significant than absolute thermodynamic efficiency, and the restrictions on loading gauge and axle weight limited the gains that could be achieved by increasing power.

    Tom
     
  13. 8126

    8126 Member

    Joined:
    Mar 17, 2014
    Messages:
    689
    Likes Received:
    690
    Gender:
    Male
    All fair points, although I do wonder if the Bulleids would have been driven on part regulator quite so much if their original reversers had been more amenable to short cut-off working. Whenever I've seen actual costs quoted for Bulleid boiler repairs in BR service (pre-downrating) they were cheaper than the equally new LNER A1 boilers, but at least once source claims the steel grade needed for the stays when worked at 280psi was difficult to obtain (which isn't necessarily the same thing as expensive, but if it means your valuable asset is out of service, it soon becomes it).

    The one clear advantage of higher pressure in the UK was to allow power with relatively small cylinders. With the Gresley three-cylinder configuration, the inside valve chest trades off against the inside cylinder; if you can make the cylinder smaller (say by increasing boiler pressure) the valves can be bigger. This happened from the A3 to the A4, and compared to the Bulleids the A4 still has quite small valves, despite having bigger cylinders. It's possible that Gresley was looking again at the power-at-speed question and wondering how it could be improved, to allow heavier trains to be worked to the existing high-speed express schedules.
     
    Last edited: Sep 15, 2018
    242A1 and Jamessquared like this.
  14. Sawdust

    Sawdust Member

    Joined:
    Jul 18, 2015
    Messages:
    466
    Likes Received:
    739
    Gender:
    Male
    Heritage Railway Volunteer:
    Yes I am an active volunteer
    Copper more expensive than steel?

    Sawdust.
     
  15. 8126

    8126 Member

    Joined:
    Mar 17, 2014
    Messages:
    689
    Likes Received:
    690
    Gender:
    Male
    Quite possibly a significant part of it. Also, I'd have to think that by then the significant use of welding in the firebox instead of lap seams would have saved a lot of time in repairs. My impression is that while the 280psi Bulleid boiler was technically successful, even if it was decided the economic case didn't stack up, the 280psi County boiler with a traditional copper firebox was less so.

    On the international scene, the adherence of British practice to copper fireboxes right to the end was a bit of a peculiarity. Steel fireboxes were perfectly successful in the UK where the water was good, either naturally or by treatment, and when the fleet was big enough that this was understood (I believe a number of steel firebox Black Fives were built and promptly sent to Scotland). 3402, as an orphan, may have been more troublesome.

    Almost brought it back round to V4s there...
     
  16. 240P15

    240P15 Well-Known Member

    Joined:
    Dec 1, 2017
    Messages:
    1,188
    Likes Received:
    1,046
    Gender:
    Male
    Location:
    Norway
    Heritage Railway Volunteer:
    No I do not currently volunteer
  17. MellishR

    MellishR Part of the furniture Friend

    Joined:
    Apr 16, 2009
    Messages:
    4,767
    Likes Received:
    2,448
    "More announcements will be made during 2018 as the project builds up steam."
    Do they mean that? There's not a lot of 2018 left.
     
  18. The Green Howards

    The Green Howards Part of the furniture Friend

    Joined:
    Feb 20, 2016
    Messages:
    9,021
    Likes Received:
    4,247
    Occupation:
    Layabout
    Location:
    Your nightmares
    Heritage Railway Volunteer:
    No I do not currently volunteer
    I'm just amazed - and strangely comforted - to learn there are still ex-LNER tenders in use as snowploughs :)
     
    S.A.C. Martin and Bluenosejohn like this.
  19. jnc

    jnc Well-Known Member

    Joined:
    Apr 3, 2012
    Messages:
    979
    Likes Received:
    1,234
    Gender:
    Male
    Location:
    Western Atlantic
    Heritage Railway Volunteer:
    No I do not currently volunteer
    Time to buy them out and convert them back to their original purpose!

    Noel
     
  20. 240P15

    240P15 Well-Known Member

    Joined:
    Dec 1, 2017
    Messages:
    1,188
    Likes Received:
    1,046
    Gender:
    Male
    Location:
    Norway
    Heritage Railway Volunteer:
    No I do not currently volunteer

    You know the A1 Trust, they certainly not lie about. :) So I think it`s a lot more left of 2018 for the A1 Trust!;)

    Knut
     

Share This Page