Toy train and wagons

The goal of this design was to be simple and easy to print and assemble. It has a rail gauge of 25mm so it should fit most wooden train tracks. It can be printed without supports but I do recommend to support the magnet holder for better surface quality on the inside. Adaptive layers or small layer height is best for the holder too to make it as round as possible. You do need quite strong magnets but my cheap neodynium ones worked fine. I didn't have spherical magnets so the magnet is inserted into a printed hemisphere.

You will need 2 8x2mm round magnets per wagon (1 for train) if you wish to connect multiple wagons. In theory there should be room for 8x3mm but I haven't tested that as I don't have that size. You could of course modify the magnet holder to fit other sizes too.

There are a couple of basic wagon designs that my kids came up with. There is also an stl with only the axles so it is easy to use slicer assembly to add the wheels to any design of your own.

Assembly insctructions

Try to somewhat straighten a piece of filament, tap the end with a flat soldering iron to form a mushroom and insert the filament into hubcaps, wheels and the train/wagon. Cut the filament so it sticks out about 3-4mm.

Flatten the end of the filament with a soldering iron to lock the wheels in place.

Mark the polarity of your magnets. Glue them in the holder so you have equal amount of both polarities facing up.

Glue the opposing polarity magnets on each side of the wagon.