Dabating between EPS and XPS foam board for layout

Hello all,

I am working on a model layout, and am considering using foam insulation board as a base on top of the plywood. As of now, I have two 4x8 sheets of plywood permanently set up with all the necessary benchwork. I am stuck between expanded and extruded polystyrene foam. The EPS is only in a 1" thickness, XPS in either 1" or 2". Here are the biggest factors:

-I am using HO Kato Unitrack that I am planning to nail to the foam for easy removal when it's time for another layout.
-I will need to climb/walk on it quite frequently. I weigh 150 pounds. The layout is directly against a wall and there is no alternative to getting up onto it.
-Noise is not an issue; I'm not particularly interested in noise-deadening.
-It will need to be cut in areas.
-I am planning on painting it at some point.

Thanks for your input!

Just to confuse the issue I used homasote and found it held track pins very well.

Cheerio John

The main underlay of a platform, whether it be luan or thicker plywood, should be braced with straight #1 lumber planks or 1x3 strips, so the layout never warps. A 4x8 should have at least 6-7 legs or 3 sawhorses. The problem is on how to fasten the track down to the foam board. You could use a thin spread of silicone caulk, or some other non hardening adhesive, that can be easily scraped off, should you decide to remove track. You would be surprised on how rigid a 3" pink foam board can be, as it never warps, even if no luan or plywood is used as a base

When building a platform you should always make it portable, and disassembleable, as if you were going to transport it to a model train convention show, or move it

I have always used regular old Flex-Track, cutting it with a Zona saw, filing the rail ends, silver rosin core soldering rail joints, scraping excess solder on inside rail joints with a brass bristle brush when still molten, replacing melted ties ... etc ... etc ... gluing it down with ballast and Elmers glue diluted with a couple drops of dish soap

I used this for an N-scale I had from 2000 to 2003, and I would be careful using the foam as I found out the hard way. It's a great idea, but I found that there's a sizing material on it which was used to help release the foam boards from extruder that causes glue not to hold well.

I nailed and glued the board using the recommended glue. I then placed my track down, which nailed down very nicely. Then one day I went to work on my layout and found the track had lifted the foam board off the plywood in sections, and had actually separated the board into bits and pieces as the track lifted up.

TANE is a lot easier to keep clean and free of dust besides the track pins don't work out and stick into passing locos.

Cheerio John