Does it really matter if a foam/cork roadbed is used on foamboard. What are the pros and cons? Thank-you.
It depends on what you are modeling more than anything else. Main line tracks should be on roadbed; sidings are normally lower than the main lines so the track does not need to be on roadbed.
We recently constructed an HO scale modular layout on 2 x 8 foot, 4 inch thick styrofoam blocks. Woodland Scenics foam roadbed was fastened down using black latex caulk and the track was also fastened with black latex caulk. For yards and sidings, we fastened the track with black latex caulk with no roadbed. Wood carpenter shims were used for the transitions.
The cork or foam roadbed is strictly for the looks of the thing. From a structural standpoint you can glue your track down to the foamboard and it will work just fine. The cork or foam roadbed simulates the ballast bed upon which prototype track is laid. Once covered with scale sized gravel the roadbed/ballast bed looks real. The prototype wanted a raised ballast bed to allow rainwater to drain out of the ballast and keep the wood crossties dry. The mainlines had deeper, fresher, and cleaner ballast than spurs and sidings. Some modelers simulate this by omitting the cork/foam roadbed on secondary trackage. Others plant deeper beds of weeds on secondary lines.
Neither type of roadbed holds track nails very well. Nor does foam. I would reccomend securing both the roadbed and the track with latex caulking compound rather than relying upon nails.
Roadbed is a matter of appearance, and is not a function of the material(s) used.
Mainline tracks are raised and provided with drainage ditches. Over the years, they get more maintenance and added ballast, so are gradually raised above their as-built level.
Passing sidings, yard leads and other tracks that get heavy usage are also raised above their surroundings, but usually to a lesser extent. ‘Bowl’ tracks in yards, tracks in engine service areas and industrial sidings/spurs are often at ground level (or ballasted to tie-top level the full width of the yard or service area) with little or no elevation. Minor tracks with deferred maintenance may disappear completely in weeds, or even submerge in mud!
I personally use a cookie-cut plywood subgrade and extruded foam cut to appropriate contours for roadbed. If someone is a sculptor with foam-cutting tools it would be entirely possible to form appropriate contours in a solid slab of extruded foam. Layering separate roadbed is a lot easier.
Given the above, how you achieve the desired appearance is best determined by your skills and the availability/desireability of materials. For example, cork roadbed is readily available and not too expensive, but it will dry out and disintegrate if used in a Mojave Desert garage where the temperature can top 120 and humidity is measured in small single digits. Extruded foam is a lot more forgiving.
Chuck (Modeling Central Japan in September, 1964 - in a Mojave Desert garage)
Some years back, I laid track right on the foamboard. At the time, I wasn’t concerned with the appearance factor of roadbed. The CON, one word: noise. Raodbed will make things much quieter.
We are talking about the 3/16" paper/foam laminate (used in school art projects/posters) aren’t we? and not the rigid foam insulation material.
Wouldn’t cork or Woodland Scenics foam tape be better and quieter?
The foamboard I’m using, is 1" pink insulation.
I’ve just started laying my roadbed. I’m using Woodland Scenics foam roadbed on my pink insulation base. I’m securing it with clear latex caulk. It’s coming along nicely. The WS roadbed is very easy to work with. Here is a photo showing the roadbed. You can see pins holding it all in place while the caulk cures:
Todd