I'm making some progress on my code 55 version of the gulf summit.
More pictures at http://www.billbentgen.com/railroad/
I made the upper level all one piece with the joint in the plywood under the tunnel instead of on top of it:
All the ramps are one piece:
I made the river bottom with 1/4" plywood to make it deeper:
Working out heights for viaduct, bridge abutments, and tunnel portals:
I hope to get cork under the track next weekend.
More pictures at http://www.billbentgen.com/railroad/
I made the upper level all one piece with the joint in the plywood under the tunnel instead of on top of it:

All the ramps are one piece:

I made the river bottom with 1/4" plywood to make it deeper:

Working out heights for viaduct, bridge abutments, and tunnel portals:

I hope to get cork under the track next weekend.