6347 Monorail Accessory Track (also 6347 Airport Shuttle Accessory Track) is an accessory set for 6399 Airport Shuttle (but also 6990 Monorail Transport System) and was released in 1991. It contains twelve straight or curved Monorail track pieces, two switchtracks (left and right) and ten support struts, as well as 30 1x4 plates as connectors for the track pieces.