Evaluating target speeds of passenger trains in China for energy saving in the effect of different formation scales and traction capacities

Based on computer-aided simulations of passenger transports by different kinds of trains in China, this research analyzes the changes of traction energy costs of these trains taking different formation scales and traction capacities with the improvements of their target speeds from the technical viewpoint of train traction calculation. It is found that the increase of the Traction Energy Cost (TEC) of a High-Speed Railway (HSR) train is as over twice fast as the improvement of its target speed. In contrast, the increase percentage of the TEC of a metro train is only about one-fourth of the improvement ratio of its target speed. Moreover, long formations of HSR trains increase their TECs due to the speed restriction by switches of tracks. Furthermore, expanding the formation scale of a metro or conventional locomotive hauled passenger train by adding trailers decreases its TEC with paying more transport time because of its decreased accelerating ability, which requires the ratio of its trailers to be determined for its traction energy saving under the prerequisite of a necessary transport efficiency of especially a busy rail line.

► We simulate traction processes of passenger transports by various trains in China.
► We study target speeds, traction energy costs and formations of trains.
► Short high-speed rail trains have less intensive energy costs.
► Long metro trains cost energy less intensively for high target speeds.
► Short locomotive hauled trains consume more energy per unit transport.