Mike & Daz,
It looks like it's worked out now. I changed some polygons to help the 3D look for tracks on terrain.
The top station in the back could be a front or just a long platform. You'll need your stations to center the main loop front and back to fit the station that you'll use.
I still think you'll be disappointed with 5" clearance on the underpass. You may get deal for nice scale engine and find that it won't make it.
Good Luck with the move today!