TRACK QUALIFICATION METHOD AND ITS REALISATION BASED ON SYSTEM DYNAMICS

Abstract

The reliable qualification of railway tracks is of great importance especially in the era of spreading higher velocity passenger traffic. It is obvious that the simple geometrical track measurement methods will be supplemented th,ough the determination of the in- homogeneities in the elastic and dissipative parameters of the rail-supporting components along the permanent way. On the basis of Dr. M. Destek's fundamental idea about an acceleration measuring wheelset of constant vertical load, the Department of Railway Ve- hicles at the TU of Budapest elaborated the plans of a Track Qualifying Vehicle and a system dynamics based evaluation method belonging to it. The measured signals of the axle-box accelerations of the measuring wheelset and the complex non-linear dynamical model of the measuring vehicle-track system make possible to identify the variation of the track stiffness and damping vs. track arc-length functions. These non-constant stiffness and damping functions are the sources of the parametric excitation of the 'track-vehicle' dynamical system. Certain fraction of track irregularities measured by traditional in- spection cars can be traced back to the inhomogeneities in track stiffness and damping. The knowledge of inhomogeneous properties of the track identified by using the proposed method leads to a more realistic cognition of the actual technical state of the track and ensures an exact basis for modelling and simulation of the dynamical processes. as well as to a more reliable prediction of the loading conditions realising both on the railway tracks and vehicles.