Surprise egg for the toy train! Print in place hinge, no supports necessary.
Once printed, use a scraper that is used to remove parts from the build plate or use something thin and pry open the middle of the egg. Once the middle is open and a little leverage is added, the lock should free itself and the egg should be openable. Be wary of using excessive force to open the egg.

Check out the toy train that goes inside the egg: https://thangs.com/model/9351

Like this model but want to put your own toy inside? See this hollow surprise egg that you can put your own toys or candy inside. Link: https://thangs.com/model/9498

Having Trouble printing? Check out other versions with more tolerances here: https://www.thingiverse.com/thing:4695529

Suggestions for improvements are welcomed.