I’ve taken the plunge and have cut the first baseboard to lower the front section in order to install the roads and underpasses under Western Avenue yard.
I took the plywood top I had cut out and installed it on the now lowered cross-bracing. I then printed a mock-up of one of the underpasses and placed it on the lowered board to test the height.
Next step is to paint the baseboard with undercoat paint to seal it, then start adding the track underlay.