Update 20181115 V02:
Now you can select the thickness you want for all walls and the track is generated right away. So no more 'tricks' in your slicer, just print your updated track.
This one generates a better inner curve, when bended.
ps1: although you get a warning, the stl is okay.
ps2: in cura, you have to create a wall thickness of 0.45, when using 0.4 nozzle, but that's cura issue.
A flex track generator for the duplo train.
This one is very flexible (without being to weak), like the initial design of romanjurt.
Printed quickly with PLA 0.4 nozzle.
Train is easily passing this track.
Check also the other customizers: