Though I'm not big on helixes this one looks as if it gets larger radius toward the top. Like a funnel. This is a great idea..Steeper the train climbs, the wider the curve and thus lessening curve drag...
Precisely. Ppuinn (Dave) was the mastermind of this engineering feat, I just cut it out and installed it per his instructions... It's a wonderful way to build a helix. Almost all the track is vertically clear, making it a snap to lay track, clear derailments, do maintenance, etc.