The Airfix B-set model was one of the first RTR carriages which purported to be based on a real prototype, and they were a real boon to GWR modellers after their introduction in 1976. I've got three pairs - two in GWR livery, of Airfix vintage, and a more recent pair in BR crimson bought when they were reissued by Hornby. Other than the couplings and wheels, I don't think there's much difference between the models despite thirty-odd years of production. They are a basic model but easy to disassemble/reassemble.

Recently I decided to tart up one of my GWR pairs, using the article in the book by the St Merryn P4 group as a guideline.

The Airfix moulding is good but includes an erroneous extra window where one shouldn't be, immediately to the right of the single guard's door on the left side of the coach. The question is, is it worth the bother of correcting this error? Generations of modellers probably never noticed it, and it certainly doesn't detract from the character of the model. Also, unless you are tackling a simple colour scheme like BR unlined crimson, I doubt whether it would be possible to rectify the window without a complete repaint and relining job.

I decided to have a go, nonetheless, and the window was filled in with plastikard, followed by plastic padding and lots of sandpapering, priming, more sandpapering etc, until I felt that no trace of the original window was visible. It's only necessary to do one window per coach, so one side remains unaltered.

Once the window was fixed, I repainted the coach in chocolate and cream, followed by lining and lettering. I've still to apply coach numbers. The glazing was from the Shawplan Laser-glaze sets, which fitted perfectly, with only one window on each side needing a tiny bit of fettling. However, if I were doing another, I'd paint the inner edges of the window mouldings in dark grey or black to disguise the thickness. I also painted the interior, although I've yet to add passengers.

The glazing parts are excellent, incidentally, as one can now see right through the coach, through to whatever's behind it, very clearly.

Onto the chassis...

The major problem lies in the curved headstocks and the general lack of detail. I sawed off the headstocks at the guard's ends of each coach, and substituted straight ones with new white metal buffers. The buffers are PD Marsh GWR pattern but rather heavy, so when I've found my stash of coach buffers I'll probably replace them again - I suspect these castings were actually meant for locomotives. I left the inner headstocks untouched, partly because they won't be all that obvious when the coaches are close-coupled, and also because I'd have to make retracted buffers, which seemed a lot of work for minimal difference. I also added 3-link couplings, not having any screw couplings left in stock. This is also a pragmatic choice as I find it a lot easier to couple 3-links than screw-links.

I then started adding chassis detail using plastic section, wire and various bits of scratch plastic. These included V-hangers, brake linkages, dynamos, and additional cross-bracing between the trusses and across the bogies between the axle boxes. It's all a bit impressionistic but it adds some welcome presence to the underframe. In the St Merryn article, they went the whole Comet chassis route, but I was happy to work with what I had. I've still to add a suggestion of the drive linkage between the dynamo and the bogie.

Finally, using a tip from Silver Sidelines:

http://www.rmweb.co.uk/community/index.php?/blog/880/entry-16042-the-ex-gwr-%E2%80%98b%E2%80%99-set-continued/

I made a simple drawing bar connection using a piece of copper clad, drilled to fit the existing coupling mounts.

I'm still not clear about the correctness or otherwise of the linkage detail on the ends of the B-sets, so for now I've left well alone.

Having gone through this, would I bother again? Yes, but not for the window, I think, as repainting and relining, renumbering etc turns an evening project into a multi-week job. I just don't think that window is enough of a deal to justify the effort. There are some models, like the Heljan Western, where it's worth putting in the hours to fix an error which throws off the character. But I personally don't think an extra window makes any difference to the look of the B-set.