Desperately slow progress, what with family commitments and other life stuff...
However, the dropped (removable) board now has its elevated sections for the bridge under the mainline and a shorter bit for the head-shunt. Once the alignment was drawn in to fit the plan, the track board supports were glued (with screws in some cases) and various fillets added for lateral strength. Thought I'd try some laminate flooring underlay foam on this layout - seems to stick down OK with PVA gl