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One Step on a Broad Road





After spending a long time reading and thinking about Brunel's broad gauge railway, I knew I had to make a start somewhere. The thought of plunging straight into a layout was proving too daunting so, I decided to buy a display case of the type sold by Antics models This case has a plain wooden base, measuring about 330mm x 80mm, onto which I could build a short length of broad-gauge (BG) track.


I wanted to build my track base using materials and techniques that mirror the original construction devised by Brunel. In searching for materials, I found that Cornwall Model Boats supply a wide range of materials and fittings, many of which are potentially useful to railway modellers. For the 'baulks' of my planned track, I bought lengths of 5mm x 2mm mahogany strip, while the transoms are made from 1.5mm x 2mm strips.


One feature of the BG trackbed is the use of pinewood packing underneath the running rails themselves. After some thought, I decided to simulate the appearance of this packing, by sticking narrow strips of 2mm squared graph paper on the top faces of the baulks. The rails themselves would then be glued over these strips. The appearance of one of my baulks, built up in this way is shown below:




I drew out a scale template, with the baulks in their correct relative positions and with the locations for the transoms marked at 8' (32mm in 4mm scale) intervals. Because the wooden strips were slightly warped, I used a straight-edge to hold them in position, exactly over the template lines, while I glued them down with PVA adhesive. At this stage, the actual running rails were not fitted. The 'bridge section' rails, to scale dimensions, were obtained from the Broad Gauge Society (BGS). I glued down one length of running rail, again using a straight-edge to ensure it ran down the centre-line of the baulk. I then used a roller gauge from the BGS to fit the other rail in position on the opposite baulk, at the correct gauge (28.08mm) for 4mm-scale track.




To complete the 'wood-work', I finally added the transoms, gluing each into position over the reference lines marked on my template.


The next task was to add ballast, which I first spread dry into the rectangular openings between the transoms, smoothing down the dry material by hand (finger tips). On the basis of photos from the Bullo Pill accident site (shown in a previous post), I chose a 'medium' ballast in dark brown, to match the ironstone colour typical of the Dean Forest area. After laying the dry ballast, I fixed it down by adding a dilute solution of PVA glue from a dropper. I use about 3-parts water to one of PVA and add one drop of washing-up liquid to the mixture, in order to make it flow freely. This last step is important as, without it, the solution tends to stand in beads on top of the ballast.





Once the ballast is in place, one really gets a good impression of the 'different' appearance of broad-gauge trackwork,





Finally, I printed a simple back-scene. I set my printer to 'draft' mode, which produces a low-saturation image that naturally recedes into the background, when photographed. I placed my old 'Gooch single', originally built from a 'K's Milestones' kit, many years ago, and, for the first time in her life, she stood on some track, in a pose reminiscent of 'official' Swindon photos of the period.





My methods were fiddly to carry out and probably not suitable for a more extensive working layout - and then there is the issue of points! One thought I had, to simplify the process, is that a laser cutter could be used to make wooden frames in the equivalent of 30' sections, onto which the rails could be mounted. Frames for pointwork could be made in a similar manner. Perhaps an idea for someone to take up?






Edited by MikeOxon
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  • RMweb Gold

Looks great Mike, I think you're right about using laser cutters for the track bases, I wonder if if C&L could help with a Broad gauge "timber track" system:-)

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  • RMweb Gold

Looks very good Mike. I have stood on the footplate of the Iron Duke in steam but with less track than you have. They laid just enough for her to stand on.

There is something very special about the broad gauge. Have you seen Ian Smiths Modbury? True it is 2mm and narrow gauge but he has modelled narrowed bulk road. There may be some ideas about points that would help you.


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Thank you Donw.  I saw Iron Duke at Didcot, many years ago, and have stood on the footplate of Firefly as well as travelling the short run of BG.  As you say, BG is 'special' and, yes, I do know and admire Modbury.  I'm somewhat in awe of what 2mm FS modellers manage to achieve :)


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Looks great Mike, I think you're right about using laser cutters for the track bases, I wonder if if C&L could help with a Broad gauge "timber track" system:-)

I doubt it as the business is up for sale.


The BG track was often mixed gauge, turnouts vary a great deal and standards changed through the life of the baulk road track. This will not be viable commercially for a very small market.

However the Broad Gauge Society has plans in this direction to provide a custom build service to members....watch this space.


Mike you have chosen to use hardwood baulks and softwood packing strips.

This is the wrong way round.

The baulks were Canadian pine = good quality softwood but Brunel found they indented with the pressure on the rail so added hard wood packing strips which also provided cant to the bridge rail as they were tapered.

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Thank you for commenting, PaulT.  I was aware that the original baulks were pine but the only pre-cut strips I found, of appropriate scale size, were mahogany.  I could claim that the fine grain of this wood forms a 'scale' impression of the softwood :)


I rather liked the idea of trying to use wood, in preference to PCB material, although I can also see the practical advantages of copper-clad material for electrical conductivity and solder-ability.


The packing is more interesting.  I based my design on diagrams in Great Western Way (1st ed.).  These show the 'original' 1838 design, with tapered hardwood packing as you describe, but also show the 'final' 1880 design with "Pine-packing, wood planking app. 6" x 1" x 8" long", shown on the diagram as lateral strips of planking. 


The photo of the track at Bullo Pill in 1868 (in my previous entry) shows the 'pattern' formed by the edges of these planks and that is what I tried to show with my graph-paper.  This is also the type of track re-constructed at Didcot, which I show in my earlier entry on 'A different type of railway'


I also noticed that the real track at Bullo Pill did not appear to have the central drain, shown in the GWW diagrams, and that the ballast looks rather coarse.


I'm interested to hear of the possibility of a custom-build service from the BGS and will watch the developments though I'm far from ready to tackle the complexities of mixed-gauge trackwork.



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  • RMweb Gold

Hi Mike, just back from holiday and thoroughly enjoyed this read. My knowledge of the BG is limited but it does look good. I was curious as to why you did not use standard BGS track components, but having just checked their site it seems as if they do not do track. For some reason I had always thought they did. But that just makes your experiments even more useful and interesting. Thanks for persisting!

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Hi Mikkel,  hope you had good hols! 


I have a couple of BGS kits to build, so they will be my next tasks.  Just as the old BG bridge rail was used for fence posts, etc., I can see many uses for the BGS rail section including, for example, stanchions for wagons.


I don't feel inclined to start on a full BG layout at present, so Amy, Blanche, etc. will not be totally neglected :)

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  • RMweb Gold

I've noticed bridge rail also being used to support sleeper-faced platforms and loading docks, so there's another possible use for them. In fact I think I may get some.


Good to hear that Amy and Blanche are still alive and well, it's been a while since we've heard from them :-)

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  • RMweb Gold

Very interesting and looking very good.  It does look different and interesting which means I am glad that the Cambrian only ever built in the 'proper' gauge otherwise I would get nothing done.  ( is 00 BG, as compared to 4mm BG, 24.57mm wide?  ;-) )

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Thank you for commenting, Chris.  The Broad Gauge Society adopted 4mm exact scale, to maintain the distinctive look of broad-gauge track.   They do acknowledge that, If wishing to run broad-gauge together with '00', as a mixed gauge line, it may be better to adopt a less than scale gauge, since the '00' is so under-scale that it will look wrong.  This is likely to cause problems with inside framed stock, however, and is not recommended.  For the present, I am not going to attempt mixed gauge!

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  • RMweb Gold
6 hours ago, The modeller said:

wouldnt dual gauge for em gauge and p4 work



I think you would have trouble with wingrails and check rails is mixing EM and P4. 


EM and broad gauge at 28mm would probably be acceptable. More concern would be the flangeways and crossings on mied gauge track.





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