lo·co·mo·tive / ˌlōkəˈmōtiv/ • n. a powered rail vehicle used for pulling trains: a diesel locomotive.• adj. of, relating to, or effecting locomotion: locomotive power. ∎ archaic (of a machine, vehicle, or animal) having the power of progressive motion: locomotive bivalves have the strongest hinges.

locomotive Engine that draws a train, usually on a railway. In 1804, English engineer Richard Trevithick built the first steam engine locomotive for transporting heavy loads at an ironworks. The first steam locomotive providing a railway service for passengers was George Stephenson's Locomotion, built in 1825. Electric-powered locomotives arrived in the late 19th century. Diesel, diesel-electric and gas-turbine locomotives were introduced in the 20th century.

locomotive pert. to locomotion; moving by its own powers XVII; of mechanism (e.g. locomotive engine, whence locomotive sb.) XIX. — modL. locōmōtīvus, f. L. locō, abl. of locus place + mōtīvus MOTIVE, after scholL. in locō movērī = movērī locāliter move by change of position in space.
So locomotion XVII. locomotor sb. and adj. XIX.