Hello there.
Just to throw in my experience of working with foamcore. I built a 009 scale narrow gauge layout about a decade ago and used it for the baseboard. The upshot? It worked and I successfully showed it at around a dozen exhibitions.
It needed to be very well braced (hopefully an image is attached of the testpiece I did prior to the proper layout), but was very simply assembled with a hot glue gun. It was extremely strong, tothe point where I can stand on the above baseboard with no problem (having said that, I'm a slight chap of 65kg!).
There are a few caveats...
Firstly, it was small, at around 100cm by 45cm. It was in one piece, so no baseboard joints of alignment to worry about. I think that may present more issues.
It was faced with thin ply - firstly for backscene and end boards, but also to protect it. Foamcore is susceptible to knocks. It is very strong as an 'entity' but is very easily dented. I also laid some thick cork as a trackbed.
You need to assure the roadbed/baseboard top is perfectly flat (as you would with any baseboard). It can be susceptible to warping, but I found that if the foamcore was perfectly flat to begin with then it wasn't an issue. I acquired some secondhand sheets (from a local supermarket) that had a slight bend in them. This certainly curve exacerbated over time.
The lightweight 009 stock was fine. Heavy items (7mm scale for instance) may present more of a problem.
Ultimately, it lasted about 5/6 years did a dozen shows and survived being thrown about quite a bit!
Would I use it again? Possibly. But I think only for a micro/small layout.
It was a joy to finish an exhibition and walk out at 16:03 with the layout under one arm!!
Only issue that it could almost blow away in a stiff wind!
Anyway, just my personal thoughts. My advice would be to make a little test baseboard (like my photo, if it has worked!) and see what you think. It is nice stuff to work with.
Dave
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