Energy Efficient and Demand-Driven Operation of Automated Rapid Transit Systems

In order to offer a more attractive rail transit system to passengers and to enhance the economic efficiency of the operator demand-driven train operation is suggested. A spatial and temporal adaptation of capacity to demand is required because passenger demand fluctuates during the day and along the transit line. In this respect, automated transit systems are known to be able to operate according to demand. In this paper a comparison of traditionally operated urban transit systems and more flexible and demand-driven line haul APM systems is presented. The influence of the vehicle size is examined with respect to demand-driven controllability of supply, traction energy consumption, fleet size and overall fleet capacity. An estimation of the potential reduction of traction energy and fleet capacity is described. In order to estimate the interaction between demand and supply an aggregated transport demand model is used. With the help of this model an optimal demand-dependent control strategy for the train headway can be derived explicitly taking into consideration the spatiotemporal distribution of demand. This strategy considers the vehicle capacity, the minimum and maximum admissible train headway and the change in demand to a change in supply simultaneously. In spite of an increased number of trains per day (shorter train headways), the overall traction energy consumption can be decreased by about 20 % with a demand-driven AGT operation compared to a fixed interval timetable.