Evaluation of onboard sensors for track geometry monitoring against conventional track recording measurements

The main objective of this paper is to assess the feasibility and accuracy of inferring key track condition parameters, e.g., vertical alignment and horizontal alignment of the rails, using onboard micro-electro-mechanical-system (MEMS) accelerometers. To achieve this aim, a prototype of an onboard data acquisition system (DAQ) was designed and installed on a track recording car (TRC) and a measurement campaign was conducted on an extensive portion of the Brisbane Suburban railway network. Comparison of the accelerometer-based results vs TRC recordings have shown that accelerometers installed on the bogie are the best compromise between proximity to the source and insensitivity to impulsive noise. Moreover, it was found that two vertical bogie accelerometers (left and right side) provide a good quantitative estimate of vertical alignment and that strong correlations with TRC measurements exist for lateral MEMS accelerometer measurements (horizontal alignment). These findings suggest that two bogie MEMS accelerometers with two measurement axes (vertical and lateral) are an effective system and can provide quantitative estimates of vertical alignment and trends in the geographical distribution of horizontal alignment