A semi-analytical model of a discretely supported railway track

The dynamic behaviour of railway track plays an important role in the generation of rolling noise as well as the development of rail corrugation. A semi-analytical model is presented that includes vertical, lateral and axial dynamics and takes account of the discrete supports provided by the sleepers. The rail is represented by a semi-analytical beam model that includes vertical and lateral bending, extension and torsion, with warping and shear-centre eccentricity. A receptance-coupling method is used to couple the rails, through damped springs that represent the rail pads, with a finite number of flexible sleepers that are in turn supported on an elastic foundation. The model also accounts for the coupling between the two rails through the sleepers. Results are presented in terms of the point mobilities in different directions, including the vertical-lateral cross mobility, as well as the track decay rates, and the results are validated by comparison with measurements. The inclusion of torsion and warping is shown to have a significant effect on the lateral rail mobility, leading to better agreement with the measured results. The response on one rail due to excitation on the other rail is also explored and the results agree well with the measurements. It is found that the coupling between the two rails has only a limited effect on the resultant track response.