In rail transport, a train is a vehicle or (more frequently) a string of vehicles capable of being moved along a continuous line of rails or other guideway for the purpose of conveying freight or passengers between points on a predetermined route. The train may be hauled or propelled by one or more vehicles designed exclusively for that purpose (locomotives) or may be driven by a number of motors incorporated in all or several of the vehicles (multiple units).

As of 2006, there are approximately 1,370,782 కిలోమీటర్లు (851,764 మై.) of railway track in use worldwide.