Abstract
With the rapid social and economic development in the world, railway transportation plays an increasingly important role. As more railway industry expands, reduction in energy consumption and pollutant emission in railway systems represents a crucial factor for further development and development of rail way transporatation. The ultimate goal is to provide higher quality service with more energy-saving. Various techniques are being developed to improve train performance in this aspect, which span from modifying the hardware structure to improving control strategy. The purpose of this article is to outline the latest development and state of the art energy-saving control techniques in railway transportation systems. The overview here is focused on two parts - driving strategy and energy storage system (ESS). Some relevant research topics and useful results are reviewed, and the research trends on energy saving are discussed.