Mark, Susan's approach is much more professional than mine. I really like her work, She and I had conversation about this project awhile ago. Very impressive person! I just do not like the lack of strength of the Atlas bridges. Way too delicate for me. The only thing I like better with my approach is that the Atlas rails imbedded in the bridge assembly are shielded from being popped out of their spikes. The fitter pieces I use at each end of all my lift outs I consider to be sacrificial in an abuse handling or contact situation.
The main line ends and the fitter pieces are adhered using Aileen's adhesive. That adhesive can be sheared off with a putty knife. It is very strong but not forever permanent.
I have had occasion to remove flex track and roadbed a few times without difficulty. It comes up clean.
Alinees tacky glue available at Michael's crafts.
The tie voids are filled1 1/4" Masonite strip aligns track. Unpainted wood is part of bridge tray
The dead weight provided flat rail head alignment while the glue dried.
Note four wire molding races around outside door.
Each wire run has quite a few track level voltage supply lines for the scores of blocks and power districts. This was all done before I discovered battery R/C. 
There is also one race which contains 110 voltage for the fascia service duplexes around the basement. No wires at floor level.
