Hackaday

A maker designed and 3D printed custom Lego-compatible train bridge pieces after finding that Lego has never released an official bridge for its train lineup. The project involved reverse-engineering Lego track geometry using L-Gauge specifications, choosing a 10-degree grade, and designing seven interlocking bridge pieces totaling nearly two meters. Printed in PLA without supports using arches for clean overhangs, the bridge mostly worked but revealed issues: some locomotives couldn't pull multiple carriages up the slope, certain carriage bogies derailed at transitions, and 3D-printed PLA couplers didn't lock as firmly as injection-molded parts. The author suggests future improvements like a shallower 5–7 degree grade and smoother transitions, and has shared the files on Thingiverse.

How I 3D Printed My Own Lego-Compatible Train Bridges