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Expanded polystyrene as road bed

3920 Views 4 Replies 5 Participants Last post by  Rail-Rider
I had an idea today, from looking at pictures of construction of the reinstated Nuneaton flyover...

Is there any reason why expanded polystyrene should not be used as the roadbed on a model railway, providing that beneath said polystyrene there is a firm foundation? It would be a hell of a lot easier for my purposes than building the L girders which would otherwise be required. I'm not thinking of using it extensively, as it would be awkard putting droppers in to the track bus (I use DCC) and burying point motors, but for a long plain track curve halfway up a hill it is much easier than cutting wood to shape- plus I'm using the polystyrene as the basic firmament for the landscaping.

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Polystyrene can easily breakup or at least particles of it, and could easily work itself onto the track and picked up by the passing locomotives. If polystyrene particles found their way into the locomotive's moving parts, could cause nasty problems. On starting up rail modelling, you are quoted a golden rule, never to run models on a track laid on a carpet for that reason - carpet fluff can damage the locomotive's moving parts.
The traditional material for a road bed is cork sheet, but this may be expensive and the trains rumble a bit. However you do get a very level trackbed.

My preference is to use 8 to 10 mm thick dense foam rubber sheets that are sold at camping shops as insulation to go under your sleeping bag. They are not very expensive. I cut the material with a Stanley knife with a new blade and a safety straightedge supplied by Squires. This is like an inverted W and provides protection for finger ends. I stick it down with white wood glue. The track is pinned and stuck to rubber with the same glue.

The advantage of using dense foam rubber is that the train rumble that you get with cork disappears, but you can still hear the clickety- click.

This very subject appeared on the BRM forumBRM. Someone there used Woodlands sceenics sub terrain base, which come in a variety of gradients, sounds like just what your looking for.
woodland sceenics
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I too would go along with a preference for rubber as a preferred option to expanded poystyrene, at least for the track bed. Apart from being less likely to 'crumb', as Colombo mentions, rubber does have sound absorbing qualities not enjoyed by 'styrofoam'. Although styrene can be quite flexible, particularly when foamed, the actual plastic is inherently quite noisy and it can be irritating to some ears with trains running directly on it.

This is not to say you can't use styrene - lots of people do, but just to mention those downsides.
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