The paper analyzes the effect of the vertical track irregularities upon the vibrations in a two-axle bogie. The method in use implies the bogie modelling and the measurement of the vibrations in wheelsets generated by the track vertical irregularities. The behaviour of vibrations in the bogie is evaluated via the results derived from applications of numerical simulation developed on the basis of the bogie model, where the inputs are the accelerations measured in the two wheelsets. The vibration features in the bogie are pointed out at according to the spectra of accelerations in the bogie frame, to the standard deviation values of accelerations and to the maximum values of the accelerations calculated against the two wheelsets.

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Rail traffic is a significant source of noise pollution for inhabited areas near the railway lines, especially because of the rolling noise generated by the trains. One of the solutions to mitigate the rolling noise emerged from trains that is increasingly being applied lately is the use of rail dampers. These rail dampers are mechanical devices designed to attenuate the propagation of bending waves along the rail from the contact areas with the vehicles wheels, thus reducing the level of rail vibration and, consequently, the noise level produced by it. Most of the rail dampers include steel plates encapsulated in rubber, working as dynamic vibration absorbers with two tuned frequencies. In this paper, an experimental demonstrative rail damper which combines the visco-elastic features of the rubber and of a thin film of oil is presented as a new solution in this field. The functionality of this kind of rail damper is investigated by experimental means and the results are shown and analysed. Also, the mechanical model associate to the functional verification procedure is presented and used to determine the visco-elastic features of the rail damper.

Abstract. Rail dampers are mechanical devices mounted at both sides of the rail web aiming to reduce the vibration along the rail. In this way, a shorter length of the rail vibrates effectively and the rolling noise is less intense. In this paper, a continuous model consisting in an infinite Timoshenko beam on multi-elastic layers is adopted for the railway track with rail dampers. The equations of motion are solved using the Green's function method and the frequency-response of UIC 49 rail is derived and analysed in terms of the receptance and decay rate of vibration depending on the possible dimensions of the rail dampers.