Brio wooden train bridge supports that uses Duplo lego as pillars.
With this collection you should be able to build as complex bridges as you like.
Increased the size of the female part with 0,5 mm because it was a little tight.
Added the SketchUp file so this thing can continue to thrive.
This thing is made to work with the standard 215 mm straight. For the first level columns use three Duplo blocks and seven blocks for the second level columns.