Trams and subways use special design Ball Slewing Rings as hinge bearings between carriage sections and carriages and bogies.

Difficult geometric conditions in the mounting structures of rail vehicles present real challenges for the design of Slewing Rings. High performance seals and long service lives are important requirements.

Untoothed Ball Slewing Rings with a diameter of 400 mm (16 in) form the hinge of the air cargo luggage ramp as shown in the picture taken at Frankfurt airport.