Hybrid powertrain for a light rail vehicle

Urban transport is estimated to account for up to 16% of global CO/sub 2/ emission, of which up to 40% is due to energy dissipated in friction brakes. Hybrid propulsion systems incorporating efficient energy storage not only allow the optimal operation of the engine at constant speed and load but also allow brake energy recovery. Ultra light rail is a form of transport that combines the environmental and user advantages of light rail with the cost effectiveness of bus operations. It is characterised by the use of small vehicles which can penetrate pedestrian areas safely and unobtrusively, and which are autonomously powered, so avoiding the cost and visual intrusion of overhead supplies and also the cost of track isolation and the need to relocate services beneath the road. ULR is therefore a viable option on routes where patronage is insufficient to justify conventional light rail schemes. This paper describes a hybrid power train for an ultra light rail vehicle together with criteria for selecting the prime mover.