I think it would also be important to me and the layouts presentation to incorporate "tatey clamps" or graves. These are where the potatoes are stored in long, low piles between harvest and distribution to the rest of the world. A couple of sidings serving graves would allow more shunting. But, (and this is a pet peeve of mine on model railways). If you're going to shunt an open wagon into a siding, it should leave it loaded and vice versa. It would destroy the illusion of the model to have an out of scale hand move potato loads in and out of the wagons. To that end I extended one of the sidings off stage behind the farmhouse so they could be loaded/unloaded out of sight, an idea I've used before.
|Holmes Hall an old concept for a Gn15 layout.|
|Wraggmarsh Farm. (line map from Stewart Squires Potato railways book|
overlaid on Google maps)