A self-propelled vehicle, usually electric, diesel, or steam-powered, for pulling or pushing freight or passenger cars on railroad tracks. A driving or pulling force; an impetus:"The US could no longer serve as the locomotive for the world economy"(George Soros). Of, relating to, or involved in locomotion. Serving to put into motion or propel forward:"It may be that the founding fathers overestimated the locomotive force of the collective and mutual self-interest"(Ian Davidson). Able to move independently from place to place. Of or relating to a self-propelled locomotive. Of or relating to travel.