Part of the Sky Track Rail System. It has extra height and slips onto both stationary and sliding rails and is used to support equipment that must be moved to the work area. Equipped with a 5/8" spigot for mounting pantographs, telescopic posts, etc.. It has 4 nylon wheels with metal ball bearings to ensure safe, smooth operation.
Similar to the manual single carriage, but it is driven with a 24V DC motor, and must be powered by an electric power supply.