Effects of Track Stiffness on Noise and Vibration Radiation in Railway and Providing Solutions to Minimize Track Radiation

Noise is increasingly becoming a major problem in Iran and other countries of the world. At the same time, many communities to reduce environmental noise are looking for ways to improve the quality of life. One of the sources of noise and vibration radiation is railway systems. The reduction of environmental noise from the operation of railway systems has become a major challenge for railway manufacturers and operators. In recent years, rail transport systems have increasingly received complaints from people living alongside lines and above underground lines. Vibration and structure-borne noise mainly occur at lower frequencies below 50 Hz. At higher frequencies these vibrations attenuate increasingly rapidly. The energy at higher frequencies is radiated as noise mainly through the wheels and the rails. Reducing the frequency of the loaded track resonance, in which the unsprung mass of the train moves on the stiffness of the track, has been shown to be effective in reducing the level of vibrations transmitted from the rail into the base of railway. This can be achieved by increasing the mass of the resiliently supported part of the track, or by reducing track stiffness. Therefore, we understand that track stiffness has significant effects on noise and vibration emissions. This can be achieved by increasing the mass of the resiliently supported part of the track, or by reducing track stiffness. Therefore, we understand that track stiffness has significant effects on noise and vibration emissions. It is known that track stiffness requirements for noise and vibration may differ from those for track life cycle performance. Indeed the requirements for noise may differ for those for ground vibration. If these issues are not relevant at a specific site then an optimum stiffness may be determined from the former requirements alone. If the site is noise and vibration sensitive then these requirements may take priority, or a more generalized optimum solution may be sought (e.g. use of resilient base plates and/or slab track). Considering the above, in this paper we review the effects of track stiffness on noise and vibration emissions. The conclusion was that For noise the stiffer the rail pads and the softer the ballast tend to produce the lowest noise levels and in the long term any influences that rail pad stiffness and ballast stiffness have on the track condition are likely to be significant. Finally, we describe strategies to reduce noise and vibration emissions.

Keywords:

track stiffness , radiated noise , ground borne vibration , ground borne noise