Sub-base options

[B.Meldon]

A bit late for my reply.
I should point out that we onbly use 1/4 (6mm) plywood for the trackbed. This is cut to the shape of the track bed and it does not cover over the entire layout area.
The trackbed is mounted on a 2x1 (planned so a bit smaller) wooden framework.
Both the trackbed and the frame work is worked out before we start building depending on the track plan we want.
The scenic areas between are made using polystyreen.
Uning this method results in a very solid yet relitivly light baseboard construction.
All the track is pinned direct to the 1/4 ply with the curves pre-bent and all sleepers pre-drilled for the pins. The point motors are secured with wood screws, but again are all adjustable.
The pins we use are short ones that do not quite go all the way through the 1/4 ply so no pins to sctratch yourself on the underside. These were previously available from peco, but sadly they no longer make them. The screws are also short so they do not go all the way through.

We do not have any warping issues, but then the baseborad joints are all adjustable and the layouts have always been stored in a heated area.

This way of doing things is 'old school' but it works for us.
That said I have not built a new layout for many years now!

Brian Meldon