Gravitrax Tile Base Ring

This part is an insert which goes into the bottom of my other Gravitrax models. It is what holds the tile in place.

Some example tiles I have created which use this part:
[Gravitrax Easter Island Head Tunnel](https://www.thingiverse.com/thing:5559243)

I remixed the same insert from 4224639. However, with the original I was having trouble getting it to fit. I needed to file it down first. My remix is a bit thinner to get it to lock in place better. Its still tight enough that I have not needed glue to keep it from falling out.