The article investigates the influence of the carbody vertical flexibility on the ride comfort of the railway vehicles. The ride comfort is evaluated via the comfort index calculated in three reference points of the carbody. The results of the numerical simulations bring attention to the importance of the carbody symmetrical vertical bending upon the dynamic response of the vehicle, mainly at high velocities. Another conclusion is that the ride comfort can be significantly affected as a function of the symmetrical bending frequency of the carbody. Similarly, there are improvement possibilities for the ride comfort when the best selection of the stiffness in the longitudinal traction system between the carbody and bogie and the vertical suspension damping is made.
This paper evaluates the level of the vertical vibrations in a railway vehicle carbody generated by the track irregularities and examines the position of the critical point from the comfort perspective. The issue is reviewed on the basis of both a „rigid carbody” model and a „flexible carbody” model, which considers the first two carbody bending modes. The model errors are calculated as a function of the speed behaviour, and the results prove that the comfort performance of a railway vehicle evaluated on the „rigid carbody” model basis are overestimated compared to the ones derived from the implementation of the „flexible carbody” model, mainly at the centre of the carbody. Similarly, a correct estimation of the critical point position in the level of vibrations requires the modelling of the structural vibrations of the vehicle carbody.