Tomy Plarail compatible train track. Tight 45 degree curve, just enough to allow a 3-car train to get around a 180 degree (4 printed sections). Useful for creative layouts that lack space for normal radius corners. I got the idea from a commercial cross-track that included switches to make the train turn rather than go straight through. I copied that turn radius. It works... just.
The model prints and fits very well in PLA. You may need to scale for other materials.