N Scale 19" Helix

These are all the pieces for printing an N scale 19" helix with a 2.5 percent grade that will hold Atlas Code 55 flex track. That means there's exactly 3 inches of rise every level. (It's technically a 481mm radius, because I'd originally intended it to work with Unitrack. It still could, but you would need to adjust the width of the slot base that holds the track. Otherwise, the side and angles and such are all correct. I decided not to go that route, as flex was easier and cheaper, and had far fewer joints.)

My old helix, made out of segments of cut, laminated plywood, suffered two problems - it warped over time due to humidity and temperature changes, throwing the track out of alignment, and also it had no sides such that any derailment had the potential to be fatal to any models involved. In the decade since I built it, 3D CAD and printing offered possibilities that weren't present when the original was built. So I created a modular 3D printed helix kit that should provid