Each module will be a "mini" layout or diorama in it's own right. At exhibitions the exhibition manager will have the choice of which "modules" he wants at his show. The caveat is that the "basic layout" of Morfa Bach and Penmaenpool MPD must be included, modules 3&4 (yet to be decided) are to be optional add ons.
Here's a block diagram showing the options that I hope will be available.
Each layout board will be 4ft long and 1ft wide. The two fiddle yard are slightly wider to accommodate the turntable type storage roads.
More as it develops.