Definition: Truck

The assembly that holds the wheel and axles, the motors, and braking systems for a trolley is known as a truck. A single truck car is one with only two axles in a frame rigidly mounted to the body. A double-truck car has two swiveling trucks, each with two axles.

A truck from a 1920s double-truck streetcar. The motors (with wires protruding) are parallel to the axles, and the pivot point is at the center.