Attaching Gargraves track to foam

most of my layout is on 2" foam supported on the edges I glue down cork road bed and gargraves track with white glue. If I need to keep in place until the the glue dries I just stick finishing nails in.

Hot glue, Liquid Nails, silicone, silicone caulk, probably other stuff at the hardware store.

Not that you can't figure this out, but buy a selection of this stuff, cut a few sections of GG test pieces and glue it down to the type of foam(s) you plan to use, and see which one(s) work best for you. Also ballast a short section or two on your choices to see how everything lives together. Pick it up and shake it a little. Everything staying in place? 

As an additional stabilizer, you can also simply stick appropriate sized nails down into the foam through holes drilled in the ties; large-thread screws (drywall for example) will grab foam fairly well if you don't fiddle with it much.

It doesn't take much to hold track down in a controlled, stable environment; not everything calls for 2X6's and lag bolts.

For the OP, this may be the ideal product from Gargraves.

These are "Sectional Track Retaining Clips" (scroll up from the link) which I've used on temporary, 2" foam, Christmas layouts in the past.  Put a "clip" over the tie; insert the supplied screw in the hole; and, twist the screw into the foam.  (GG product no. 901.25).  The clip fits between the center rail and an outside rail; you could use two clips per tie is you chose to do so.

One benefit is you aren't drilling holes in ties or messing with adhesives; you can use the clips as frequently as you want, but probably multiple clips on each elevated segment would be best--the clips aren't expensive. 

If it was me and I was just using it to see if the track plan will work I would use sheatrock screws down between the ties. With the inclines you will have places where there is foam between tracks. I used this on my old track plan When I was happy with it, I glued it all down with Liquid Nails for foam. It will hold and be a pain to get back up if you ever change your mind.

Thanks guys. 

I will see if I can temp screw down the track to the foam for the time being.  When it is time to make it permanent i plan to use white glue brushed to the underside of the ties and then ballast glued in place.  

I wouldn't use anything and didn't on my old layout. Everything stayed in place just fine with the glue used when glueing down the ballast.

-Greg