Tightening up of trackwork and expanding expansion gaps.

[John CutlerParticipant]

Neil Docherty of this forum has asked if anyone knows how to avoid trackwork tightening up. I have the same issue plus the opposite of expanding gaps.

I suspect the causes are due to differential expansion and contraction of the rails compared to the underlying supporting material. Traditionally this would be wood which is notorious for expanding with heat or damp but not contracting to the same degree on cooling or drying. Just think of all those warped timber sheets we see in the big DIY warehouses.

The only answer I can think of is “floating track”. At its simplest this would entail a curved section of plain track being secured (pinned) at one end only and the rest being allowed to float. In case this seems too good to be true, this simple solution raises all sorts of questions. For starters the rail must be free to slide through the chairs. There probably needs to be some flexibility in the sleepers (restricting us to plastic flexi-track?). The ballast needs to be loose!

I am not sure if this could be made to work with straight track but I guess slight buckling of the whole formation would be acceptable (so flexi-track again?).
How one can apply this to turnouts is beyond me!

I have tried using as long rails as possible to minimise gaps, including through the stock rails of turnouts. This involves ignoring some of the biblical commandments of building turnouts and probably explains some of my wayward track formations. My conclusion is that the result is mixed and probably not worth pursuing.

Any thoughts or tips on minimising rail expansion issues, please?

[Stuart FirthParticipant]

Confession time – most of my track is pcb, which has no opportunity to move about of course, and is glued to the cork with wood glue. Despite this it has survived happily for 25 years in lofts that experience temperatures from 0-46 degrees Centigrade. I put this down to the basic strength of pcb track and plenty of expansion gaps. Perhaps the gaps do become quite large when the temp is close to freezing but I’m not up there to see it… The only other track I have is some sidings made from Ratio track bases and these have been fine too.

[Neil DochertyParticipant]

I’m using steel rail and PCB sleepers; layout lives in my study. Sydney climate can be humid but generally pretty pleasant (I live in shorts and tee shirts all year round when not working) and not much temperature change in the study. At times I’ll do some testing and short wheel base wagons (as layout set early LMS days almost all stock is either 9′ or 10′) derail; when checked gauge is under? Doesn’t tend to happen at points?

[Douglas FirthParticipant]

Neil,

You are not alone. In Perth we can have a wide variation in temperatures and many a layout has had expansion and contraction problems. OK your study should be a buffer to this but check the temp changes as accurately as you can to make sure the temp doesn’t spike at some point during the day or time of the year. I grew up in Sydney and also did my training as a book and paper conservator there . We had to continually check the temp and humidity, there are large changes in Sydney. Sorry this is so long,

Douglas Firth.

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