Toy switching engine for Wooden track

A 3d printable toy locomotive designed to work with the very common wooden track you see all over the place.

I wanted to design some additional toy trains, since even though there are a number of track objects, there are few actual printable trains. In other designs I've seen too, they use a hook and loop system over the magnets. I've designed mine to use 5mm magnet balls, like the old buckyballs. It seemed reasonable that these would be easy to come by, and they seem to work well. Since I'm