After a couple months of just breaking in the staging level and working out the bugs (and retiring from the Air Force, and going camping, and taking a trip to South Dakota…), I finally starting building again yesterday. I’ve got the first turn of the first helix that connects staging to the wye at St. Charles complete. 1.5 more turns to go.
This is the second time I’ve used this method to build a helix, and I really like it. I call it the “double pinwheel”–each level is essentially two layers of 8 identical trapezoids of plywood, each put together like a pinwheel with the two layers overlapping. It’s very easy (once you do the math to figure out your trapezoid and cut a master), it’s very forgiving, and it’s very strong after the glue dries.
Some particulars on the helix. It’s a 24″ radius helix that gains 4.5″ per turn. That works out to a 3% grade which should work fine for all the trains that will use it. The track you see looping around it (in the black painted area) is the continuous running loop connection. I was able to let a short string of cars run away from the top, and they negotiated the switches without a hitch at warp speed, even the #4 with REALLY short points going into the L&N staging yard you can see in the photo above (phew).
I’ll write a full article on the double pinwheel helix soon as I don’t know of anyone else who uses this method (let me know if you do). In the meantime, here are some progress pics.
Here’s a closeup of two pieces of the helix going together–I alternate top, bottom, top, bottom, gluing and clamping as I go 
My limiting factor for how much of the helix I can build at once is clamps–it takes me about three sessions to build a level allowing about 90 minutes for glue to dry between sessions