- For other uses of this term, see Bogie (disambiguation).
A bogie is a wheeled wagon or trolley. In mechanics, a bogie is a chassis or framework carrying wheels, attached to a vehicle. It can be fixed in place, as on a cargo truck, mounted on a swivel, as on a train carriage or locomotive, or sprung as in the suspension of a caterpillar tracked vehicle.
Railway cars
A bogie in the UK, or a wheel truck, or simply truck in the U.S., is a structure underneath a train to which wheel axles (and, hence, wheels) are attached through bearings. If they are used there are usually two for each carriage, wagon and locomotive, or alternatively, they are at the connections between the carriages or wagons. The connections of the bogies with the cars allow a small rotational movement around a vertical axis. Most bogies have two axles, but some cars designed for extremely heavy loads have been built with up to five-axle bogies. Heavy-duty cars may have more than two bogies using span bolsters to equalize the load and connect the bogies to the cars.
Usually the train floor is at a level above the bogies. However, for a double decker this applies only at the bogies: between them the bottom deck can be lower.
There are low floor trams without bogies.
See also: Diesel multiple unit
Tracked vehicles
Some tanks and other tracked vehicles have bogies as external suspension components. This type of bogie usually has two or more road wheels and some type of sprung suspension to smooth the ride across rough terrain. Bogie suspensions keep much of their components on the outside of the vehicle, saving internal space. They are vulnerable to antitank fire, but can often repaired or replaced in the field.
See Suspension (vehicle).
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