Having solved this technical issue with fill styles, I can now determine that the maps will be called “rail diagrams” and “rail maps” and the former will be the plain white background, the latter will be on aerial photography. So every map will be produced with an aerial photography background because of the free reuse of the Linz aerial photography being possible. I think it is likely I will come up with a thinner border style for buildings if I decide to use a style similar to the above instead of a solid filled rectangle style. The thicker style will continue to be used as now for sites.
The below is the likely building/structure style to be used. I like the open circles for turntables.