Compatible with most wooden train toy sets (like Thomas the Tank Engine). My kids requested a section of track that was flexible, so I designed this in SolidWorks. It is very flexible, and can both compress and extend as needed. Great for filling in sections with odd geometry.

I made a few iterations, revising for better compatibility, and strength (the first couple were snapped).

SolidWorks file is for SW2015. STEP file is available if you can't read SW2015 files.

See my other designs for train tracks as well:

Rail Connector - http://www.thingiverse.com/thing:1779150
T Junction - http://www.thingiverse.com/thing:1579594
Equilateral Y Junction - http://www.thingiverse.com/thing:1576147
Cross Junction - http://www.thingiverse.com/thing:1779661