The 8 threaded rods and the first few sections of the helix are now in place and ready for cork roadbed. The track from the lower yard will enter the helix from the bottom and the track from the upper year will enter after 1 turn, about where that wrench is in this photo.
To create a smooth transition for the track from the lower yard to start the climb I used my router to carve out a 1/4 inch depression in the 3/4 inch base then glued and stapled a 1/4 inch plywood sub road bed in place. This will gently start the climb up from the flat surface.
That first single track section of sub road bed meets another 1/4 inch thick sub road bed section that completes the first 1/2 inch of climb and meets the first true helix section. It also flares out from single track width to double track width.
One of the more tedious parts of using the threaded rod helix design is threading all those nuts onto the rods. After trying several ideas to make this go easier and faster, I settled on using the attachment for a disk sander without the sand paper. The rubber backing has enough grip to move the nut around. This works in both directions by reversing the rotation of the drill motor.