On-board tracking of polygonal wear propagation on a measuring tram

To study the propagation of wheel polygonal wear in a case study, a long-term test was performed using a measuring tram to collect continuous data during regular operation. The collected measurement data were localised using a map-matching algorithm. An increase in the signal power of the axle box accelerations was observed continuously over a 5-month measurement period and a mileage of 33,000 km. The concept of virtual measuring stations is introduced to separate excitations from the wheel and rail. The harmonic out-of-roundness is tracked using order decomposition of axle box acceleration, and an exponential growth of the dominant polygons is observed. A self-reinforcing effect of polygonal wear is proven. The quantified growth rate indicates a doubling of the polygon amplitude after approximately 20,000 km. According to the representative distribution of velocity and curve radius, polygonal wheel wear occurs in the frequency range 48–75 Hz. As a root cause, a P2-like mode dominated by axle arch bending is discussed, which falls within the wear frequency range, particularly for embedded tracks. The standard error of regression (SER) and the distribution of the residuals εres(f) are suitable for evaluating the quality of virtual measuring stations.