Why are the vehicles mounted above the guideway rather than below?
• Switching. The running surfaces for supported vehicles are continuous through switch sections, whereas with hanging vehicles, there must be a slot in the guideway through which an arm that supports the vehicle passes. Thus, in a switch section the support element inside the guideway must pass across the slot, so the supporting load must be transferred to another member. In the Monocab PRT system this required an extra set of wheels that engaged slots in the top inside of the guideway. With maglev the load would probably be transferred to a set of electromagnets. This extra load-transfer means adds extra weight and cost, and reduces reliability. The bottom line is that the fundamental requirement of switching is much easier with supported vehicles. • Visual Impact. A group at the University of Minnesota worked in the PRT field for 13 years before deciding it was necessary to initiate the design of a new PRT system. During this time, we conducted three international conferences on PRT
