Terranaut: Biotech Train (Patreon)

Some basic sketches for the train in Terranaut. I still need to figure out what its literal guts look like... the twin engines have tanks of sugar fuel that are used to power the muscles of the pneumatic piston system. The oxygen intake at the nose lets air in to pass over a huge respiratory surface, then exit through the gill-like outtake holes on the body. 

Also here's a rejected and slightly cursed locomotion method: secret giant chicken legs