Wuppertal Schwebebahn – July 2010
Supended vehicles cut Parasitic Mass™ of the vehicle. These suspended trains are a step in the right engineering direction, but the packet size is too large. People travel individaully or in family size groups. Making the packet hold 50-200 people means the networks will not service the individual needs of the customers.
Good historical summary
https://www.youtube.com/watch?v=pv8MTufKRQQ