A new approach to the analysis and presentation of vertical track geometry quality and rail roughness

A new approach on enhancing the assessment of track geometry quality and rail roughness by means of train-track interaction simulation and wavelength content analysis is presented. The dynamic model includes vehicle, track and linearized wheel-rail contact with moving irregularities and can be simulated either in the frequency domain by using FFT or in the time domain by constructing a filter function based on system identification technique. The system is suitable to calculate wheel-rail forces for very long track sections and for several vehicle types under a wide range of travelling speeds since the computational scheme is very efficient (300 km/s on a standard computer). With numerical results we demonstrate the potential benefits of improving conventional track geometry inspection methods and highlight short defects (0.5-2 m) as a cause of high dynamic wheel-rail interaction forces. By using a wavelength weighting of measured rail toughness a new improved way of analyzing rail roughness data is also presented. This improves condition assessment of tracks and rails and will enable the track engineer to monitor the track in a better way. (C) 2008 Eric G. Berggren. Published by Elsevier B.V. All rights reserved.