This train (runs on carpet or track) has a different face on each end.
It is made from 3D printed parts (total cost less than one dollar). The wheels and hubs are small parts, so exercise appropriate care with small children
Design and print files available at:
Print the body (which includes the axles) and print the wheels. Place the wheels on the axles.
Print the hubs and glue (superglue) the hubs to the end of the axles.
Without decoration, the car looks like this.
Paint the face on each end, and paint the hubs.
You now have a train with two faces.