Train of Blocks and Magnets

This model train can be seen as the 3D printed equivalent of a model train which is build up out of wooden blocks for childs to play with. You can add blocks to wagons, connect the wagons, etc. This is similar but now from 3D printed building blocks. The building method is different, in this case magnets are used to snap the blocks onto the wagons and locomotive.
If you indeed use this for children to play with, then I would advice to glue the magnets into their locations. The design is such th