Thanks Wayne, Ill try that.
I can't see why this should be much of an issue at all, unless you're worried about parked rolling stock not staying parked. Flex track isn't going follow abrupt changes in elevation. If you're putting down the cork with caulking, simply add a little extra at those abrupt changes. Another option is to allow the track itself to smooth things out: where there's a change in the thickness of the base, affix the track to, and only as far as the edge of, the higher piece. Allow the track to drop to the lower level of its own accord - could be 6" away or maybe 2' - affix it at that point and beyond. Next, go back and ballast the portion which is "floating". When the ballast has fully hardened, the track will be well-supported on that slight and natural grade. I've used this method with great success, especially where I've extended or moved track off the plywood roadbed and onto the plaster-on-screen scenery (widening a curve or extending a siding). This is pretty-much how the real railroads do it (minus the plywood, cork, and/or plaster, of course).
Wayne
The foam is alread attached to plywood underneath. It is possible that i didnt spread the liquid nails out evenly enough. Looks like i will have to shim under the cork maybe with some styrene.
I doubt that it was 'compressed' from stacking. Remember, the product is 'extruded' through a die and 'cut' every eight feet. You will notice that the ends are not as thick. I suspect that the middle of the sheet is very close to the 2" mark. We ran into this at our club layout. We used Plaster of Paris to build up where the ends meet. It sounds like a lot of work, but it went quite fast. With normal cutting to shape, you do not have very many of these 'low' spots where tracks cross.
Jim
Modeling BNSF and Milwaukee Road in SW Wisconsin
Compressed that much, I doubt it. Remember this is a building material whose standards are in a range of tolerences much greater than we would like for model railroading. Now on to the question, just use the caulk that you are adhearng the foam to the framing in different thicknesses, done all the time in the trades.
I would add shims on the benchwork beneath the foam to level it, or notch the bottom of the foam to bring it down if necessary.
It takes an iron man to play with a toy iron horse.
Ive been noticing as I go along that I am finding differences as much as 1/16" - 1/8" in the thickness of the 2" foam that I am using as a sub roadbed. I assume this is because the foam was stacked about 6ft high at the lumber yard and got slightly compressed toward the bottom of the pile. What is the best way to keep my track level, so that I do not have uncoupling issues?