Another small step... I've now glued (or "No More Nails" but we all know it's actually glue) two lengths of 1200mm timber to each module end. The "front" one is set 6mm back from the edge of the module ends to allow 6mm MDF to be attached to it. The next step, once the glue sets, is to screw the lengths to the module ends. I'll do the usual risers to support the track bed.