This is basically a chassis designed for those of you who wants to build your own train. The body in the picture is just the imrpovised example I did in the tutorial videos to show an example of how it could be done.

The chassis is based on the bogies from the GP38 locomotive: https://www.thingiverse.com/thing:4390600

In the example I'm using only one motorized bogie, but if you want you could of course put one motorized in each end. What you need depends on your track, if you have a lot of slopes and bridges it might be a good idea to have two motorized bogies for extra traction.

All screw holes in the chassis except for attaching the bogies are M2. The bogies are attached using M3.

This project has been done on request and I have not printed it myself. I think it should be OK but I cannot promise, so let me know in the comment if you have any problems. This project is not meant as a beginner tutorial for Fusion 360. If you are new to the software, I recommend that you go through a couple of beginner tutorials first to learn the basics.
It is also important to note that this is a DIY project that starts at a medium level of complexity in terms of mechanics and electronics so it is expected that you have basic knowledge of electronics, Arduino and mechanics.

For electronics, I recommend checking out the Hectorrail 141 locomotive for example of how to use the NodeMCU as a controller: https://www.thingiverse.com/thing:2575667

Remote control if you don't want to use a smartphone or a tablet: https://www.thingiverse.com/thing:3252986

Suitable track: https://www.thingiverse.com/thing:4408535