From my website: KFConcepts, 1999 –
“The K’NEX inverted car has seen many changes. The first design only seated two across and barely resembled an actual inverted car. The latest car seats four across and the train is able to turn on the X axis and Z axis. Two color schemes are built with this design: Green/Yellow and Purple/Orange, to coincide with 1999’s Dueling Dragons at Universal Studios Islands of Adventure.
Each train can be customized to use all three axes. Two axes are used for handling control. A train can be built to a full length, however a three car train is built for handling control and minimum use of pieces.”