The layout was designed using XTrkCad. I decided to use it because it was free and had many elements (such as Peco turnouts, and Atlas crossovers) already defined in the program.
There were many considerations I had to make when developing the track plan for the layout. The room itself was the largest obstacle. I had to come up with an accurate diagram of the room before I could begin to design bench work and the track plan itself.
In my design I didn't want to have any duckunders. I was forced to have one because I needed keep access to the bathroom and entrance into the Helix. There is also a duckunder near the doorway but its is 55" off the ground. It is a single track acrosse the aisle to connec the left shelf to the island.
Once the benchwork design was completed the track plan could be completed. The lower level track plan is complete and has been implemented (See the construction page). The upper level is still a work in progress.
The upper level still has some work to be done but the design is close to done.