Condition monitoring of vertical track alignment by bogie acceleration measurements on commercial high-speed vehicles

The paper describes a methodology for condition monitoring of rail track, which exploits acceleration measurements recorded by in-service high-speed vehicles. Estimates of the vertical track alignment are computed from bogie vertical acceleration with suitable linear regression models, relating synthetic RMS indicators representative of vehicle dynamics to track geometry parameters recorded by a diagnostic train. Two different linear models have been introduced, specifically devoted to the investigation of the overall track quality (by means of the RMS of the geometry parameter) and to the identification of isolated defects that may require maintenance intervention (through the track geometry peak value). The proposed solution has been specifically designed for high-speed applications, where trains travel at constant maximum speed for most of the journey. The methodology has been tested and validated against direct measurements taken by a diagnostic train. It allows to correctly reproduce the evolution with time of the railway line defectiveness, both in case of energy content and peak value. This result poses the basis for the development of methodologies for track condition-based maintenance.