im still developing my layout design but i was wondering how thick should foam be that will be the base for the layout 2",3"....? and my old layout it what just plywood without the foam layer and i could nail down the track, how do you nail down or secure the track with the foam? cause i dont think nails hold well in foam.
Depends - if you've got plywood under it, the 1" thick stuff is fine. The major thing to consider is how much sculpting below tracklevel do you want to do - it needs to be at least that deep.

My first section consisted of a pair of 1 1/2" sheets layered. That way I could cut away a good chunk of the top sheet to get down to some "sub-main" level industry.
k ill haft to figure that, but at the moment i dont thinkg any of my industry goes below main level, im might do a llittel sculpting to make a river, im thinking maybe 2" thiick
If the only reason foam is used as the top level of the layout base is to have below the surface features the question is why. A plywood layout base can have below level track level features easily. Just cut away the plywood.


My stream is two and a half inches below track level on a solid tabletop.

Gluing track!!!!!I have enough trouble nailing it down. Glue is so messy and I am so inept.

Just a thought
Glue is actually better than nails unless you are handlaying track (not something for the inept).

Actually, what I use on flextrack is latex acrylic caulk. It dries clear and you have a bit of a chance of being able to pry it up later.

There was an article in Model Railroader about 2 years back on how to use the stuff. I laid about 8 or 9 feet of track in the past couple days using that method.

As for foam thicknesses, let's look at what it looks like:

This is two of the "1 inch" sheets":

This is the "2 inch" sheet:

This is the "2 inch" sheet carved for a creek - I later took the center of the creek down to wood:

This is a single "1 inch" sheet - I'll probably do a bit of sculpting, but it will need to be shallow by necessity:
JeffShultz said:
Glue is actually better than nails unless you are handlaying track (not something for the inept).

Actually I have found handlaying track easier than flextrack it is just more time consuming but the results are better.

Just at thought
Very true Harold, but then again some of us to have a needed patience to accomplish that. ALTHOUGH, I am seriously looking at using the CVT tie strips with ME rusted rail, I just need to practice with that barge cement they mention.

Big issue with handlaying, I see, is concrete ties, so if I use ME rail I can switch to ME or Atlas flextrack for the concrete sections.