The basic design for the layout is four 4’x2’ boards, or rather 1200mm x 600mm. It’s a sad fact that most layout sizes are governed by multiples of available plywood, MDF, Sundeala or whatever. Typically, Sundeal comes in metric sizes, whereas plywood is imperial (1220mm x 606mm).
Each board will be build from 3”x1” softwood, with 2”x1” softwood bracing. Tops will be 6mm plywood topped with 9mm Sundeala. Why? Sundeala is an easier surface to model on, can be sculpted, and has good noise deadening qualities. The 6mm ply is for structural support (Sundeala is known to sag) and to have a strong base to screw point motors to. This structure was recommended by Alton Model Centre, and the bloke there even showed me a board he’d constructed himself. It may seem like overkill, but I’m only going to do this once (hopefully) so better get it right.
I pondered long and hard about legs (as one does!) and decided on a slotted-in structure. Basically you create a hole for the legs and they just slot in, bolted firmly. Easier to set up than trestle-type legs and no bracing required (I hope!). Easier to construct too.
Leg length is 1200mm, a good height for both modelling (you can crawl under the boards if required) and viewing. I’ll fit adjustable feet for levelling purposes.
Main board 1 will have legs at either end. Boards 2-4 will have just one set and be supported by the preceding board.
In planning the layout I decided to add a 2’x2’ board at either end to allow the trains to run behind the scenic area into the fiddle yard. These will join on to the end boards by being bolted on, but I’ve also designed a cantilever support for additional strength. Sounds fancy but it’s basically a brace from the end-most leg to the underside of the 2’x2’ board.
And that's it. I have little carpentry skills but I do like planning so the wood will be delivered in handy 1200mm lengths, which should be easy to cut to size. The challenges will be cutting an 8' x 4' sheet of plywood (the merchant can't cut a single sheet...) and constructing the butt joints (half lap joints are beyond me and I'd have to do 12 joints per board - life's too short).