locomotive (adj.)
1610s, "pertaining to movement," from French locomotif, from Latin loco "from a place" (ablative of locus "place;" see locus) + Late Latin motivus "moving" (see motive).

From 1650s as "moving from place to place;" by 1814 as "having the power of moving by itself. The noun meaning "engine which travels on rails by its own power" is from 1829, short for locomotive engine, which is attested from 1814. A locomotive engine used without rails was a traction engine, which became tractor.