There have been a variety of mixes of "Steam Engine" issued over the years, but this rare 45 version has never seen an official CD release. Chip Douglas pressed this single and sold it at the 1983 Chicago Monkees convention. It features a unique vocal take from Micky (along with some weird stylings by Micky at the start of the song), as well as variations not heard on other mixes.
The B-side, "Rainbows," was another Chip Douglas song recorded by Davy in 1981.
Be sure to check out these informative links for more information about this release:
Recap: Monkees Farewell Tour
Dolenz sings Nesmith