Tink i smiled when I read your original question, because I was thinking of the steam donkeys, that pulled the logs from where they were felled over to the landing.
The power of the steam donkeys was virtually infinite; what you tried to do was get up as much steam pressure as possible, and that meant cutting the volume of water (waiting to be boiled off into steam pressure) to the barest minimum. The problem was, if the volume of water got too low and the steam pressure too high, the boilers could explode!
So if the donkey puncher survived his first years in the woods, he was an engineering genius of how to get the most possible power without the boiler exploding and killing everybody. Eventually they changed to diesel power (diesel-pot vs. steam-pot), but the diesel donkeys never had much power, not like steam.
Anyway, in the early timber industry those things were used dawn to dusk, no chance for rust, although you can still see them sitting around Pacific Northwestern woods abandoned and they are certainly rusted out now!