You quickly learn to create your own assembly fixtures when you have access to only two hands.

North end sections (that transition the track from upper to lower level) being installed.

I cut radius templates from dense foam and taped them together Later changing to a glued splice for durability) to provide a rough plot for the framing needed. I did the northern end first and then replicated it to the south end with a few revisions.

This is one of the removable sections that allows to the pool gate if required. The sub-deck, foam road bed, and track are also configured to follow the framing when removed.