The application of track deflection measurements made by the video gauge

This paper presents direct track deflection data measured by the Video Gauge (VG), (a Digital Image Correlation method) that is used to remotely determine track stiffness characteristics. Two cases are discussed. Firstly, the deflection performance of two novel ballastless trackforms are coupled with an analytical model to assess their stiffness properties for known train loads. Secondly, the performance of a bridge transition is evaluated under live train passages by the VG; the traffic loads are assumed based on train type to allow track stiffness interpretation from a number of train passes. A track deflection bowl is assessed to show the performance of the transition. The paper initially discusses the DIC technique and the importance and assessment of track stiffness. It then presents the VG deflection data, the global support stiffnesses and deflection bowls. It shows these novel methods to be consistent with other approaches of track stiffness evaluation. It concludes on how this methodology can be utilised in the railway industry for assessing trackbed performance of critical zones without the need for track possessions.