Abstract Summary
Railway tracks experience differential settlement due to the stresses induced during train-track interaction. The characteristics of this vertical profile are a key parameter when scheduling track maintenance operations. Regression or machine learning can be used to extrapolate historical changes in profile, however this approach is challenging when linespeed is increased or new rolling-stock is introduced. As a solution, this paper presents a novel approach to investigate the effect of increasing train speeds, adding additional passenger movements and adding additional freight movements to an existing line. The model combines empirical settlement laws with 2.5D finite element theory, where the track-ground structure is modelled explicitly, and multi-body train-track interaction is considered. The stresses are computed using a hybrid frequency-wavenumber and time-space approach, considering non-linear track-soil material behaviour. It is shown that higher speeds result in elevated dynamic forces and cause a faster rate of deterioration of track geometry. The model also investigates the effect of adding additional train movements to a passenger line. It is shown that additional movements increase the rate of track degradation, particularly if the additional traffic is freight. This is because freight vehicles typically have one only layer of suspension, thus generating elevated dynamic forces compared to passenger vehicles.
