Removing acrylic caulking from cork roadbed

[P5se Camelback]

... It is much more likely that the wood shrank as the moisture content went down, and this is what caused the buckling. ...
... Rail gaps wouldn't protect against the benchwork wood shrinking. I'm thinking that using ripped plywood instead of dimensional lumber is a good idea.

I've used dimensional lumber for 35+ years. I have never had a problem with "buckling" of any sort. I have built layouts in the Northeast, the South, the West Coast and now in Sub-Tropical Florida. I have had to deal with buying lumber in the dead of a snowy winter day and taking it down to the warm basement. I have bought lumber in 85% humidity and taken it inside to 45% humidity. No buckling

But ... many years ago, when I was a teenager, I read some advice about building benchwork ... it may have even been in Linn Westcott's "How to Build Benchwork" book ...

Bring the lumber into the space where the benchwork is to be built ... and then resist the temptation to build for a week! Allow the lumber to adjust to the conditions in the room or the basement, or wherever you are going to build your railroad. I have followed that advice. I still use dimensional lumber ... and I use plywood for sub-roadbed and homosote for roadbed and I have never had a problem with buckling.