i then decided to do an outer loop with two central spirals that linked together. i originally wanted to use the shakey bridge from a plarail set, but didnt like how it looked and couldnt get the girders to work properly to support things. i eliminated the bridge and went to a dogbone shape instead, which works much better.
on the left side, i will build above the sprial until it is level, and then make single circles that can each run a single train, allowing more characters, and also filling the airspace at that end of the bed below the "roof" of thomas' cab.