power train vs wheelwork

power train and wheelwork both are nouns.

Word	Noun	Adjective	Verb	Adverb
power train	Yes	No	No	No
wheelwork	Yes	No	No	No

As nouns, wheelwork is a hypernym of power train; that is, wheelwork is a word with a broader meaning than power train:

power train: wheelwork consisting of a connected set of rotating gears by which force is transmitted or motion or torque is changed
wheelwork: mechanical device including an arrangement of wheel in a machine (especially a train of gears)

power train (noun)	wheelwork (noun)
wheelwork consisting of a connected set of rotating gears by which force is transmitted or motion or torque is changed	mechanical device including an arrangement of wheel in a machine (especially a train of gears)