A GWR branch line in gauge 3; Broad Gauge

Discussion in 'G3' started by geoff_nicholls, 10 May 2018.

  1. geoff_nicholls

    geoff_nicholls Western Thunderer

    For my next gauge 3 project, I thought I'd have a go at something different, and you can't get much more different than Brunel's broad gauge. The current thinking is to produce a micro layout for exhibition, inspired by the Abingdon and Faringdon branches, set in the mid 1850's. I chose this period as it fits in with another 'narrow' gauge project. It's a bit more interesting than other G3 stuff I've tried, because virtually nothing is available to buy. Also because until six months ago I knew virtually nothing about the GWR broad gauge. Finally because my mentor and co-conspirator, Unklian, likes to do things right, so it's the G3 equivalent of S7 or P4. The Broad Gauge Soc would probably call it BG13.5 . Track gauge 95mm.
    Ian has turned a set of Slaters wagon wheels to the new standard, and I've bought a set of Mark Wood's "Lion" wheels which I plan to use to build a Leo class 2-4-0ST. I spent a few hours at Didcot last week, checking out the real thing. Once Reading is out of the way I'm going to build a test track. I'm hoping to stick with my preferred curve radius of 3 metres.
    This is what I'm thinking of:
    Disused Stations: Abingdon Station

    If anyone else out there has been thinking about doing something similar, perhaps we could work together on this?

    20180411_175311.jpg 20180505_095421.jpg
    Ian G, isambardme, Wagonman and 14 others like this.
  2. Spitfire2865

    Spitfire2865 Western Thunderer

    What are the major differences between G3 an your new BG13.5 regarding wheel track standards?
    I look forward to progress.
  3. Heather Kay

    Heather Kay Western Thunderer

  4. geoff_nicholls

    geoff_nicholls Western Thunderer

    The standards proposed by Ian are:

    Track Gauge 95mm
    Check rail gap 2mm to 2.5mm (3.5)
    Over Checks 90.5 (88)
    Wheels Back to Back 91mm (89.5)
    Tyre Width 6mm to 7mm (6.8)
    Flange Width 1.6mm (same)
    Flange Depth 1.5mm to 2mm (2 - 2.3)
    The G3 standards, if applied to broad gauge, are in brackets. I myself find the 0.5 difference between the check rails and the back-to-back a bit worrying.

    I'm not really a willing convert to these standards, but both Lea Siding and Aldeburgh Harbour have long stretches of inlaid track, and the G3 soc standard gap of 3.5mm is really noticeable. I want to avoid that in the future, this seems a good time to start.
    Spitfire2865 and jamiepage like this.
  5. Spitfire2865

    Spitfire2865 Western Thunderer

    The check gap seems the only major challenge for dual gauge pointwork. I wonder if there is a workaround to allow it. Even then, that .5mm overall doesnt seem like itll work well. Might need to loosen that for the model to go through. Especially at points for rigid wheelbase vehicles.
    Im sure you will be able to figure it out.
    Last edited: 11 May 2018
  6. unklian

    unklian Western Thunderer

    It might be as well to point out that the over checks dimension is a maximum and the back to back a minimum . With track gauge at 95mm and both check gaps at 2.5mm the over checks would have a minimum of 90mm . Given a flange width of 1.6mm the back to back could be as much as 91.8mm . The best dimensions are somewhere in between of course . The check gap of 3.5mm given in the existing Gauge 3 standards is the main problem as it is way too big, my rewriting of the standards was mainly to try and correct this .
  7. geoff_nicholls

    geoff_nicholls Western Thunderer

    For myself, discretion is the better part of valour, there won't be a turnout on my planned layout, I'm hoping to use a sector plate. Nor am I planning any inlaid track. So, although I will include them on a test track, I won't need check rails on the layout.
  8. unklian

    unklian Western Thunderer

    Bridge rail ????
  9. geoff_nicholls

    geoff_nicholls Western Thunderer

    Oh Yes!
    But probably not for the test track.
  10. victorianman

    victorianman Member

    Very good to see exact scale standards applied here; the sheer size of the track makes it that much more worthwhile.
    unklian likes this.