The effect of the wavelength of lateral track geometry irregularities on the response measurable by an instrumented freight wagon

Condition monitoring of railway track geometry using instrumented in-service vehicles has been the subject of extensive research aimed at replacing or enhancing the data provided by dedicated track recording vehicles. Lateral track irregularities present difficulties compared to vertical irregularities due to the lateral clearance between the wheel flanges and the rail head. Wheelsets don’t necessarily follow the lateral trajectory of the track. Simulations of a freight wagon with three-piece bogies negotiating both discrete and cyclic lateral track irregularities showed that the resulting lateral displacements were highly dependent on the wavelength of the irregularities. The wheel/rail profiles also had a significant effect whilst the effect of speed was relatively minor. These findings highlight the complexities of identifying exceedances of track geometry standards using only inertial sensors on instrumented freight wagons.