Questions about foam board

[rogergperkins]

(IMHO) Extruded polystyrene foam as available in many home supply stores has become indispensable as a model railroad building material.
My own layouts are zero grade, but have hills and low area all accomplished with the extruded polystyrene foam.
I tried the beaded type and did not like it because it is messing to cut and shape and not as sturdy as the type intended for use by the building trade.

[shark_jj]

This is all great information, thanks guys.  One final question that arose during a discussion with a friend yesterday.  Do you notice any difference in keeping the track perfectly level between the three types of subroadbed, plywood, foam insulation, or ceiling tile.  My going in assumption is that by sanding the cork you make this a non issue, but I'd be happy to hear about your experiences.

John

[rogergperkins]

I am using Kato Unitrack so keeping it level has not been an issue for me with the current layout; I have fixed a few sections in place with straight pins from Joann Fabric because of alignment challenges of my track plan.  I have never glued Unitrack in place.

[Bendtracker1]

...Do you notice any difference in keeping the track perfectly level between the three types of subroadbed, plywood, foam insulation, or ceiling tile.
John

I haven't noticed much, although I've had to sand a couple of the ceiling tile joints due to different thicknesses, but just a couple of swipes with the sanding block took care of that.

I agree using the extruded polystyrene foam if your doing scenery like this:


But most of my layout will be flat with a only one river and a few sloughs with culverts and the likes, so I just need to slice them out and smooth them with some lightweight spackling compound.  When I have scenery about track level I'll use the extruded polystyrene foam.

[LV LOU]

I've had no issues whatsoever with the foam.Unlike materials like Homasote,Plywood,ceiling tile,ETC,foam is totally unaffected by moisture,heat,temperature,ETC.A piece of plywood could theoretically sag a little between studs over time,that's nearly impossible with 2" foam that's properly supported.I'd NEVER go back to wood based products on my railroad,not only for the stability,but the scenic possibilities are amazing.I was never truly happy with any railroad I built until I started carving foam..