Bogie

A bogie or  truck  is a wheeled wagon or trolley. In mechanics terms, a bogie is a chassis or framework carrying wheels, attached to a vehicle, thus serving as a modular subassembly of wheels and axles. Bogies take various forms in various modes of transport. A bogie may remain normally attached (as on a railway carriage/car or locomotive, or on a semi-trailer) or be quickly detachable (as the dolly in a road train); it may contain a suspension within it (as most rail and trucking bogies do), or be solid and in turn be suspended (as most bogies of tracked vehicles are); it may be mounted on a swivel, as on a railway carriage/car or locomotive, or additionally jointed and sprung (as in the landing gear of an airliner).