Running resistance - results and analysis of full-scale tests with passenger and freight trains in Sweden

This paper presents experimental results of running resistance tests. Running resistance is determined for conventional passenger trains, freight trains, and the X2 high-speed train. The influence of variables such as speed, number of axles, number of coaches, axle load, track type, and train length is studied. The running resistance is expressed in a general form by a second degree polynomial. The three terms in the polynomial are functions of these variables. The magnitude of the first term is speed independent and varies with number of axles, axle load, and type of track. The second term varies with speed and train length. No influence of axle load is distinguished. The third term is related to the air drag and varies with the speed squared and train configuration. It can be divided into two parts. One part is constant and depends upon the front and rear of the train, and another part increases approximately linearly with train length.