Remixed the Brio bridge from theinternal - I liked the arched design, and the matching stackable-ness of the original Brio pieces; but wasn't keen on having to print multiple pieces and assemble with screws.

Designed this alternative; print with the top of the track touching the print bed (upside down), and supports on print bed enabled - there's only a small amount of support surface area needed here, but prints as a single piece with no assmebly required. It doesn't have the cool top arch anymore, but it's still practical :)