LATERAL TRACK FORCES AT HIGH-SPEED CURVING - COMPARISONS OF PRACTICALAND THEORETICAL RESULTS OF SWEDISH HIGH-SPEED TRAIN X2000

This paper initially describes the main features of the radial selfste ering bogies, which have been developed for the high speed train X2000 , suburban trains and other applications. One of the main goals with t hese bogies is to reduce lateral track forces at high speed curving. T his development has been supported by extensive theoretical investigat ions parallel to practical tests and verifications. Since around 1973 the main tool for theoretical analysis has been rime domain simulation s of non-linear vehicle-track models under influence of perfect and ir regular track geometry. There are models for vertical/longitudinal and for lateral dynamics. The models are assembled and utilised in a spec ialised computer program, SIMFO, and in a more general computer code, GENSYS, the latter having full 3-dimensional capability. A frequently used model for lateral dynamics of a four-axle bogie vehicle with 37 d egrees of freedom (DOF) is shown as an example. In order to avoid an u nrealistically stiff lateral coupling between wheel axles and ground, this model contains lateral track-ground elasticity and/or lateral and torsional DOF for each wheel. By comparison with measurements it is s hown that characteristic quasistatic and dynamic behaviour can be simu lated with accuracy.