Hi everybody...
I have my track plan done and I am ready to start building my benchwork in the next week or so. I have a removable bridge section that I will be installing as a part of my benchwork. My questions is what kind of problems have people had with track alignment after the track has been laid and will the cork have any issues with vertical track alignment due to compression or expansion.
Thanks,
Ryan
As long as your roadbed is well adhered to a stable surface, and as long as the roadbed is planar to the extent possible (no dips or changes in its thickness that make it bumpy to the ties), you should be fine...if I understand your question. What may get you is changes to compression axially due to humidity, mostly in the subroadbed and the benchwork material supporting it all. So, while the tracks and roadbed may be quite happy, what is below them may not be happy if subjected to great changes in temperatures and humidity. Humidity is the biggie, though, since the roadbed and rails won't change much unless we are talking about swings of 30-40 deg Celsius.
What many guys do is set the roadbed according to plan, and then sand it along its length to get it planar. Then, add the rails using glue, but leave a small gap, maybe 3/32", every 6-8' to allow for expansion. This will only work, though, if your materials are already at a nominal level of humidity content when they are cut and placed together as a layout. If you start with wood that is very damp and then dry if over several weeks, don't expect things to line up later. Gaps that were 1/16" in the rails will likely become 5/32" or greater. Your layout will wobble because fasteners are no longer tight. Similarly, the other way around, if your wood is nicely dried, and then you leave it in damp surroundings after construction, you can expect screw heads to disappear into the wood, or to tear their moorings altogether.
I hope this helps. The cork should not compress so much that the ends of your bridge rails don't align well with the rest of the bench rails. Not in my experience, anyway.