bogied

Bogied is a railway term used to describe a vehicle that is fitted with bogies, the wheel assemblies that support the car or locomotive beneath the frame. In contrast to vehicles with rigid frames and fixed wheel axles, bogied vehicles separate the wheelsets on a frame called a bogie, allowing independent movement. The term is commonly used in reference to passenger cars, freight wagons, and some locomotives.

A bogie consists of a bogie frame, two or more axles with wheels, an axlebox/bearing housing, suspension components, and often braking equipment and traction motors. The primary functions are to improve stability, ride quality, and curve negotiation by allowing the wheelsets to pivot and absorb shocks.

Common configurations include two-axle bogies used on most passenger cars; three-axle bogies used on heavy freight wagons or locomotives; and various suspension designs such as coil springs, leaf springs, air suspension, or secondary dampers. Some bogies house traction motors (powered bogies) while others are unpowered (trailing or idler bogies).

In operation, bogies are coupled to the car body by a bolster and pivot to ease negotiation of curves. Maintenance focuses on bearing wear, wheel tread condition, alignment, and suspension integrity. Modern bogies may incorporate bogie-frame stiffness optimization and radial or active suspensions for smoother rides and better high-speed performance.

See also: Bogie, Rail vehicle dynamics, Wheelset.