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The Pentewan Railway in Cornwall was possibly unique in having three* gauges in its lifetime. Christopher Hawkins built the original rai...

Monday, 31 December 2012


This winter has seen me finally get around to ballasting. I started on the big scenic section which is destined to be exhibited in 2014 but was so pleased with the results that I vowed to get rid of as much of the yellow peril foam underlay as possible. I realise having this colour everywhere for so long was really getting to me and colouring (sorry) my judgement. With hindsight I wished I had painted the foam grey or suchlike before any sleepers were laid.

I needed to ensure the ballasting did not affect the ability of the track to float on the underlay which rules out PVA which would have locked it up solid. Luckily Copydex which is flexible, can be diluted and used in much the same manner. Tests done some years ago proved it works, however some ballast has come away in places possibly because it was applied too thinly. This time I set out to find the optimum methods and glue mix.

A lot of the PLR was ballasted with china clay waste as it was cheap and readily available. Earlier this year someone mentioned both chinchilla dust and sieved cat litter as suitable and cheap ballasting materials. Having acquired a bag of each, I then had to dash both my daughters' hopes as to the true purposes of my purchases - they are still demanding the appropriate animals be acquired.

I thought about making a ballast spreader of the type both commercially sold and similar DIY versions, but in the end a teaspoon, fingers and a cheap small paintbrush ended up being the best method of spreading. I laid ballast on about 9 yds of track length with pointwork in a couple of hours. In places I followed a useful tip from a forum somewhere, which was to paint neat glue alongside the track which holds the sprinkled ballast in place.

I had read that diluted IPA (Isopropyl alcohol, not the type of beer) was a good wetting agent and dilutant. It might be for PVA but not Copydex - adding some to a Copydex/water mix almost instantly formed a large ball of solid rubber. Dripping diluted Copydex into an IPA wetted ballast produced similar surface lumps.  I also tried screen wash as a dilutant with no perceivable benefits, so resorted to good old washing up liquid. I made up a decent quantity of water with a generous slug of washing up liquid in it (you could see the colour) and then used that in my spray bottle and to dilute the Copydex, mixing the latter only when about to be used. I didn't measure the ratio used but is probably more than 10 parts water to 1 part Copydex, i.e. very thin, like skimmed milk.

My first spray bottle sputtered out blobs too which rather upset my carefully laid ballast - especially the chinchilla dust. My daughter suggested trying a chemist and I found a small pump action spray for £1.59 which produces a gentle mist. The final technique was to mist something like 12" ahead and follow in a zig-zag fashion with diluted Copydex using a dropper between each set of sleepers between, and either side of the rails, and trying to avoid the sleeper tops and rails themselves, using enough so the ballast fills up with the water/glue mix (as if swamped with milk). To ensure it is properly stuck down (and as the mix is so thin) I repeated the glue dropping the next day before it had dried out. In fact it took several days to completely dry out and as I discovered it also forms a very effective short circuit until dried.

Both the cat litter and chinchilla dust darken when wet. The cat litter also seems to expand a little so some tamping down was done whilst still wet. When dried it reverts to the original natural colours, so much so it looks like it is still loose, but a quick prod will show it is not. To finish off I cleaned the railhead with a block of MDF and then my leather strip rail cleaner (I never use anything abrasive) and some scraping of sleepers and cleaning out the point flangeways etc., interspersed with hoovering. As it is very flexible it is also possible to squash down any raised ballast lumps.

And after (the gully will be weathered and varnished in due course)

Rust stains have appeared in places from the spikes specially when the ballast has (intentionally) covered the sleepers. I think this can be hidden as part of weathering which will be final stage - along with planting some vegetation/weeds etc.

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