Shunting a 12 wagon rake of wagons over the level crossing there would be approximately 7 wagons plus loco going off scene. I may well start with a standard FY board at this end to see how I feel operating the layout at home. This would give me more time to either develop the scenic FY idea for home use or just build an extra scenic board to add between the level crossing and FY for exhibiting.
For through layouts, one solution is to have removable loads in open wagons so a freight train can work full in one direction and work back later empty.
It's the clay wagon that cause me problems. As the tarpaulins are a touch fragile I'm reluctant to continuously take them off then put them multiple times during an exhibition. I'm trying to discover when clay wagons stopped travelling via Wadebridge along the North Cornwall Line. If this was still happening in late 1950s I'll need track running around the back to move wagons between the FYs. Other open wagons with loads that can be removed will be built to be removable. I already have some 16ton minerals with removable loads but feel they need improving.
Further thoughts...I may build twins of other opens which have fixed loads. This would allow me to alternate loaded and empty wagons within goods trains end to end. e.g. a conflat with a container within a train would travel from Wadebridge to Bodmin North. At Bodmin North I'd have a train with an empty conflat which would return. Then this would happen in reverse.