Energy Consumption and Running Time for Trains

The accuracy in determined energy consumption and running time of trains, by means of computer simulation, is dependent upon the various models used. This thesis aims at developing validated models of running resistance, train and of a general driver, all based on full scale testing. A partly new simple methodology for determining running resistance, called by energy coasting method is developed and demonstrated. An error analysis for this method is performed. Running resistance of high speed train SJ X2000, conventional loco hauled passenger trains and freight trains is systematically parameterised. Influence of speed, number of axles, axle load, track type, train length, and train configuration is studied. A model taking into account the ground boundary layer for determining the influence of measured head and tail wind is developed. Different factors and parameters of a train, that are vital for the accuracy in computed energy consumption and running time are identified, analysed and finally synthesized into a train model. Empirical models of the braking and the traction system, including the energy efficiency, are developed for the electrical locomotive of type SJ Rc4, without energy regeneration. Driver behaviour is studied for freight trains and a couple of driving describing parameters are proposed. An empirical model of freight train driver behaviour is developed from full scale testing and observations. A computer program, a simulator, is developed in Matlab code, making use of the determined running resistance and the developed models of train and driver. The simulator calculates the energy consumption and running time of a single train. Comparisons between simulations and corresponding measurements are made. Finally, the influence of driving on energy consumption and running time is studied and demonstrated in some examples. The main conclusions are that: The method developed for determining running resistance is quite simple and accurate. It can be used on any train and on any track. The running resistance of tested trains includes some interesting knowledge which is partly believed to be new. Mechanical running resistance is less than proportional to the actual axle load. Air drag increases approximately linearly with train length and the effect of measured head and tail wind on the air drag can be calculated if the ground boundary layer is considered. The developed train model, including running resistance, traction, braking etc. is quite accurate, as verified for the investigated trains. The driver model together with the train model in simulations, is verified against measurements and shows good agreement for energy consumption and running time. It is recommended to use a driver model, when calculating energy consumption and running times for trains. Otherwise, the energy consumption will most likely be over-estimated. This has been demonstrated for Swedish ordinary freight trains.