In BC, a steam donkey is generally known as a stationary steam powered winch which would have in the logging early days, functioned as what is known today as a yarder. It has a generally vertical, silo appearance and comprises of a vertical firebox on which sits the water box and coils, valves, a lower (usually comes out near the base) horizontal external piston which turns an eccentric which through reduction gearing, turns usually, a really big winch. There are tons of them kicking around as derelict in a lot of BC forests, especially in those where the "big" wood was found such as in the temperate coastal and interior rainforest areas.
On the prairies, we always referred to the old monster steel wheeled steam tractors as "Steam Jennies". At demos, I have seen those old guys pulling six plow blades attached to a separate wagon, complete with a dedicated crew of men to run the plows, breaking virgin prairie sod at a good clip, with nary a wheeze.
I just checked with dr. google and it appears the name "steam donkey" frequently is used as a nick name for both a stationary steam winch and antique steam tractors, so it might just be a regional thing.
I am sure someone will pitch in with a picture of the winch version, be danged if I can find one in my stuff, even though we are tripping over them all the time.
On the other hand and barely related to the thread topic, what about a Mastodon made from
derelict and abandoned farm equipment?.... (although the cultivator teeth will be a tip off that it is not
that old)