What are train wheel assemblies commonly referred to as?

Train wheel assemblies are commonly referred to as "trucks." A truck is a frame that supports the wheel sets of a rail vehicle. The role of a truck is crucial, as it not only houses the wheels and axles but also allows for movement around curves on the track. It typically includes components like the wheel sets, axle, bearings, and suspension.

Understanding the structure and function of a truck helps in grasping how trains maintain stability and maneuverability when traversing various terrains and rail configurations. This term is distinct in the railway context, differentiating it from the other options, which do not accurately describe the assembly of wheels and axles used on trains.