This is so cool. I hope they are burning coal to produce the steam to go full steampunk.

Someone should do a water wheel powered one next.

> I hope they are burning coal to produce the steam to go full steampunk.

That's a commercial off-the-shelf hobbyist steam engine, they prescribe using smokeless fuel tablets like [0].

Coal would just make a bunch of soot and a big mess in general.

[0] https://www.amazon.com/Esbit-1300-Degree-Smokeless-Tablets-E...

I wonder how efficient a water will would be? Made with current tech, bearings, etc.

I don't think modern gears and bearings will improve efficiency by more than a few percentage points. Most of it is in the size of the wheel, and the energy of the water.