Uncertainty analysis of track degradation at railway turnouts aided by a multi-body simulation software

Abstract

Railway turnouts are elements exposed to an accelerated track degradation when compared to plain line track. The particular and complex wheel/rail contact characteristics in railway turnouts make the contact forces acting on the wheel/rail interface particularly high. As a consequence of the train/track interaction force magnitude, track degradation is more accelerated here, having a big impact on the general costs used for track maintenance. The contact phenomenon has a stochastic nature due to the great number of variables involved in the interaction problem. Moreover, the uncertainty levels associated with each of the aforementioned variables require in-depth stochastic analyses that reflect the real variability of the parameters which characterize the dynamic interaction and consequently the degradation problem at railway turnouts. The scope of this work is to perform a probabilistic assessment of a railway switch and crossing, aided by the multi-body simulation software, GENSYS. The critical track components with a major impact on track degradation are identified by means of a sensitivity assessment based on the elementary effects method while the uncertainty is assessed by using the Monte Carlo simulation method. The proposed methodology used to evaluate the probabilistic problem is a suitable approach to identify the railpad stiffness, the mass of the bogie, the damping value of the primary suspension and the ballast stiffness, being the critical parameters with the highest impact in the uncertainty analysis of track degradation at turnouts.