A railroad car, railcar, railway wagon, railway carriage, railway truck, railwagon, railcarriage or railtruck, also called a train car, train wagon, train carriage or train truck, is a vehicle used for the carrying of cargo or passengers on a rail transport network. Such cars, when coupled together and hauled by one or more locomotives, form a train. Alternatively, some passenger cars are self-propelled in which case they may be either single railcars or make up multiple units.

Rail transport is a means of transport using wheeled vehicles running in tracks, which usually consist of two parallel steel rails. Rail transport is one of the two primary means of land transport, next to road transport. It is used for about 8% of passenger and freight transport globally, thanks to its energy efficiency and potentially high speed.