Lego duplo compatible train switch track!
I will try to make a nicer version, but this works - tested. Prints in two parts that need to be put together (see image).
Latest version (v3) should also work with hand operated duplo trains (they are a bit wider with connecting rods on wheels).
See it in action: https://www.youtube.com/watch?v=uhAiMwLUwuU
Sketchup file included in downloads.
No supports needed, just print with enough infill.