“If you trains ever derail in a tunnel, it’s a real pain.
Get round it by using an old picture frame in the scenery. Bin the glass and use the frame and the backing, face down, in the scenery.
Just take the backing sheet of to get inside your tunnel – and as most railroad layouts have bushes, fences or vegetation it’s easy to hide the ‘ridge’ of your frame.”
Alan
This is the best ive seen
You can use any type of foam, shape it as a mountain or hill. Then mix an appropriate color grout to “pour” over the foam, letting it run down the foam creating whatever shape you desire.