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.

BR Double blastpipes

Discussion in 'Steam Traction' started by Alasdair B, Jul 31, 2026 at 2:18 PM.

  1. Alasdair B

    Alasdair B New Member

    Joined:
    May 7, 2020
    Messages:
    6
    Likes Received:
    14
    Gender:
    Male
    Location:
    Leeds, Yorkshire
    Heritage Railway Volunteer:
    No I do not currently volunteer
    I am interested in the upgrades to draughting of various locomotives by BR by installing double blastpipes in the 1950s. Can anyone confirm the diameters of the single and double blastpipes fitted to the following locomotives?
    GWR Castle 4-6-0: single double
    GWR King 4-6-0: single double
    BR Standard 4-6-0 Class 4MT: single double
    BR Standard 2-10-0 Class 9F: single double
    Regards,
    Alasdair
     
    Alasdair B, Jul 31, 2026 at 2:18 PM
    #1
  2. std tank

    std tank Part of the furniture

    Joined:
    Sep 20, 2005
    Messages:
    4,031
    Likes Received:
    1,162
    Gender:
    Male
    Occupation:
    Retired
    Location:
    Liverpool
    Heritage Railway Volunteer:
    Yes I am an active volunteer
    I take it that you are talking about the diameter at the top of the blastpipe caps?
    Castle single ? double 3-7/8"
    King single ? double 4"
    Std 4 4-6-0 single 4-5/8" double 3-3/4"
    Std 9 2-10-0 single 5-3/8" double 4"
     
    Last edited: Jul 31, 2026 at 7:08 PM
    std tank, Jul 31, 2026 at 6:49 PM
    #2
  3. David Mylchreest

    David Mylchreest New Member

    Joined:
    Nov 17, 2025
    Messages:
    96
    Likes Received:
    59
    Gender:
    Male
    Location:
    London
    Heritage Railway Volunteer:
    No I do not currently volunteer
    That's interesting! The commonplace view is that the double blastpipes were based on the Dean Goods; clearly not.
     
    David Mylchreest, Jul 31, 2026 at 8:38 PM
    #3
  4. std tank

    std tank Part of the furniture

    Joined:
    Sep 20, 2005
    Messages:
    4,031
    Likes Received:
    1,162
    Gender:
    Male
    Occupation:
    Retired
    Location:
    Liverpool
    Heritage Railway Volunteer:
    Yes I am an active volunteer
    The double blast pipe caps are all of Swindon design to drawing No. SL/SW 1310.
     
    std tank, Jul 31, 2026 at 8:44 PM
    #4
  5. Jimc

    Jimc Part of the furniture

    Joined:
    Sep 8, 2005
    Messages:
    4,182
    Likes Received:
    4,950
    Occupation:
    Once computers, now part time writer I suppose.
    Location:
    SE England
    Heritage Railway Volunteer:
    No I do not currently volunteer
    By the end of their lives the Dean Goods had received many upgrades, and IIRC I've seen a drawing suggesting the draughting was last changed in the late 30s or early 40s, so it was probably Swindon state of the art for that period, and very likely bore little or no resemblance to what they had when new. Its therefore not impossible that the dimensions on a 1940s designed Dean Goods blastpipe were much the same as those for a double blastpipe on something larger.
     
    Jimc, Aug 1, 2026 at 9:00 AM
    #5
  6. jma1009

    jma1009 Well-Known Member

    Joined:
    Mar 16, 2013
    Messages:
    1,393
    Likes Received:
    1,639
    Gender:
    Male
    Location:
    ynysddu south wales
    If I remember correctly, the only use of The Dean Goods arrangement doubled was for BR Duke of Gloucester. It wasn't used for any other double chimneyed loco.
     
    jma1009, Aug 1, 2026 at 11:32 AM
    #6

Share This Page