If you can stretch the canvas tight so that there are no wrinkles, then yes, it will work just fine for a backdrop.
Most theaters, TV studios, and movies use canvas stretched on a wooden frame to make walls. and other flat surfaces.
I'm not really sure about how you intend to execute your other idea. If there is a gap between two 2D scenery elements, the forward of the two will cast unrealistic shadows on the rearmost, unless you light it very carefully to conceal this (and even then, a photographic flash will reveal your trickery). I would say that the effort involved in doing this would far outweigh the effect. My impression is that you will be forever calling people's attention to your cleverness with the backdrop, when their eyes are naturally drawn to your trains and foreground scenery.
Connecticut Valley Railroad A Branch of the New York, New Haven, and Hartford
"If you think you can do a thing or think you can't do a thing, you're right." -- Henry Ford
Are you speaking of an artist type canvas? Never have heard of anyone using it, but that desn't mean there aren't any using it. I used to do oil paintings with my mother, years ago. Guess my qestion would be how the paint covered the texture of the canvas. You can give it a try using your choice of oils or acrylics and see how it looks. You can always paint it over later if you decide not to use it for a backdrop.
As for having the backdrop set back from your hills. Many folks paint distant (and not so distant) hills right on the backdrop and have buildings or closer hills in front of that. For my first one I did only sky (with a couple of poor clouds) on the backdrop and gently rolled the top of the foam hill in front of it back a little before it met the backdrop. I then covered the hill with puff ball trees with a few spruce trees sticking up in the forrest.
Do a little experimenting and let us know how it looks.
Good luck,
Richard
A thick acrylic or oil paint will cover the texture in the canvas. You can also prep the surface with several different sealants first (diluted white glue being one).
I also think you'd get away with it, although one thing you don't want is a textured sky.
I have a roll-up canvas awning that I plan to use as two temporary backdrops by painting both sides. It's a very fine canvas texture and I will give it a coat or two of gesso first to fill in the weave as best I can.
Mike
Modelling the UK in 00, and New England - MEC, B&M, D&H and Guilford - in H0
Anything will work with enough effort, but stretching and priming and mounting will be a problem, though solveable. 1/8 inch masonite will be much easier. If you want a little texture, prime the back side. It is just easier.
Vuzzez:
My concern with the canvas is that over time the paint may start to crack, especially if you put it on thick enough to smooth out the texture of the fabric. The canvas will expand and contract with changes in humidity and this will put stress on the paint. If your train room climate is very stable you may not have a problem but in a normal household environment I think the variations in humidity could mess up your work, particularly in Canada with the seasonal variations.
Dave
I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!