[Garratt]

Heavy steam traction engines were notorious for sinking in unfirm ground. Frank Bottrill patented his dreadnought wheel to solve the problem.
He used them successfully on his steam traction engines.
She is no steamer but Big Lizzie built by Bottrill in Melbourne, Australia had little problems with traction on her dreadnought wheels.
The tractor had a 60 HP single cylinder Blackstone oil engine running at 215 RPM.
With full fuel tanks could run for 3 years at 1~2 MPH.
She cleared many 1,000's of acres of trees and stumps with a cable and ground crew of up to 16 men.

Andrew

 

[Garratt]

Perhaps that was 3 years of working days. There are also tanks in the trailers. It could hold over 5,000 gallons of crude oil.
Not sure why Bottrill had to have his tanks so full. Maybe there was none where Big Lizzie worked so he took his own supply.

Andrew