From These Organizations:
Since the 1990′s a group of dedicated SME’s (SUSTRACO, Tram Power, Parry People Movers and TDI (Transport Design Int.)) have been engaged in the research, development, testing and operation of highly energy efficient cost effective systems known as Ultra Light Rail (ULR).
ULR has done for Light Rail (LRT) what LRT did for Heavy Rail reducing the weight and complexity of the system leading to cost reductions of up to 70% when compared to similar LRT products and services. Until ULR come along rail based tram and light rail system were restricted to larger urban areas where the high cost could be justified.
ULR has changed all that by making rail based system no more expensive then bus based systems such as BRT, guided bus, trolley bus meaning that even small towns can have the opportunity to use rail transport with all its’ long term cost advantages.
Other advantages include lending its self to the use of sustainable energy sources and a number of on-board energy storage and recovery systems – batteries, ultra capacitors and fly-wheels are all used by different manufactures. Thus brake energy recovery and reduced energy demand means that ULR may use less then 25% of the energy per passenger Km then a bus based system. The following link http://www.ultralightrail.com/faq.html may provide answers to questions that you have.