Effect of uncorrelated sources assumption on railway vibration modelling

In classical railway vibrations studies, wheel-rail contact points are considered as point sources uncorrelated from each other. This approach gives a more reliable source for vibration impact assessment studies along railways which can be based on in situ experimental measurements or on numerical models. This is also related to the fact that the combined wheel-rail roughness that cannot be perfectly known. This postulation allows using a line spectral force density combined with a line transfer mobility. However, all sources are generated by the same system (train, railway and ground) and are in reality correlated in some way. This paper investigates the effect of sources decorrelation on ground vibration estimation. Numerical models in time and frequency domain are used allowing comparisons for several identical configurations. Results are discussed in detail to understand the effect of sources uncorrelation approach.