That's Really cool.
I was at an event in Brooks Oregon Called the great Oregon steam up and I saw some old steam tractors down their.
You should try to build a Herr Engine. Their is only one left in operation at the steam up in Oregon.
Quoting Neil Armstrong
What bits did you use for the boiler barrel, firebox sides & inner flywheel?
Hi, The inner flywheel is the top half of grey "Turntable 4 x 4 Square Base(3403c01)" I used the bottom half of a black one for the start of the boiler, then used 2 "Wheel 20 x 30 Technic' (4266)" followed by a "Technic Cylinder 4 x 4 x 2 with 3 Pin Holes and Center Bar' (41531)" the capped with a 4 x 4 round plate and then a 3 x 3 dish....