These are toy train tracks I designed. They should be compatible with Ikea Lillabo and Brio train sets, although I haven't tested them together.

There are other models for similar train tracks, but this provided a good excuse to learn more about OpenSCAD, so I modeled them from scratch using measurements provided by a Toy Train information site.

The OpenSCAD code is located here.

They all print-in-place easily. I printed them at 0.2mm layer height, but I think 0.3mm would work just as well.

The only model that requires supports is hill.stl, I used prusa-slicer to paint supports around the top where the overhanging connector is.