Time-lapse motion control rig for GoPro

This uses mostly off-shelf parts with a 3D printed base to make a time-lapse motion control rig out of G-Scale toy train track.

Sample videos using this rig:
https://vimeo.com/groups/171005/videos/56310148
https://vimeo.com/groups/171005/videos/52572663
https://vimeo.com/groups/171005/videos/51877097

The rig has a controllable speed between 15mm and 90mm per minute, using the 5402:1 gearbox (use a different gearbox configuration for speeds outside this range.)