I wasn't quite happy with all the existing options so I took ideas from several places and put them together to make just what I was looking for. I hope it fits your needs as well!
I designed these to fit my Brio and compatible tracks, so I can't promise they will fit every brand of track out there, but they do fit Brio.
I recommend using my gcode files if you have a mk3, or use my 3mf file to modify for other printers. I took a lot of time to optimize everything for a fast print (0.3mm layers) that has the precision where it matters. So no support material, but some settings tweaks with a modification block to improve bridges since this model does have some long bridges.
The author marked this model as their own original creation.