Last summer ('08/09) we had a few days where the mercury went over 40c, this caused the rail to buckle in the Mudgee area cause I apparently did not leave enough of a gap for rail expansion. When I got around to doing something about this the rail had contracted back to 'normal' and I thought I'd wait for another hot one to come along so I could then mark what tracks gave me problems. Guess what - no more hot days came until this summer - so what happened - nothing - I did nothing on the layout to any great degree until earlier this summer when we had a few more hot one's just before Christmas, this time I marked which tracks had buckled, took them apart and cut about 1mm of the end of the tracks in question - I had to make about 4 cuts in the Mudgee area, some more in the lower portion of the layout - Mudgee is now running OK & I'm progressing on the others. I've included a couple of photos of the track after it was taken apart but before I cut it back - you can see the track overlaps the point rails by about .5mm, hopefully the bit I have cut off the ends will have solved this problem - time will tell.
I also had a short devlop in the same area. I think that was something to do with the gaps in the points (which I cut with a razor saw) closing up and thus shorting out. I've re-cut the gaps and glued a piece of 10thou styrene in the gaps and then trimmed the styrene back to be level with the rails. Hopefully that will be it - the trains certainly seem to run OK with no shorts in this area now.
I'm hoping for another hot day or too just to see how it all hangs together. Ahh the joys of building a layout in an attic - and yes the roof space is insulated as are the walls.
Was just about ready to post this when well - we had a few more hot ones - was 40' a little while ago followed by a 38 day - no sign of any more buckling in the Mudgee area so I'm hoping all will be OK for the future - Now to finish the other areas that have experienced track buckling.
That's it for now...