According to Member State reports compiled by the European Environment Agency (EEA) in 2010, railway noise affects about 12 million EU inhabitants at day time, with a noise exposure above 55 dB(A), and about 9 million at night time, with a noise exposure above 50 dB(A). In fact, the real figures are undoubtedly higher since the EEA’s European noise mapping initiative concentrates on agglomerations with over 250,000 inhabitants and on main railway lines with over 60,000 trains per year.
The discussion about railway noise has become very important in se-veral European countries as railway transport increases and plays a more important role in greening transportation. To reduce railway noise pollution, passive measures at the place of disturbance can be distinguished from active measures at the noise source. The most important passive methods used to reduce the impact of railway noise on the environment are noise protection walls and insulating windows, and for the most part action plans and investments of the member states concentrate on these methods.
Nevertheless, these methods have only local effect and impose huge investments in protecting extended parts of the railway networks, as stated in a report published by the European Parliament in 2012, a report which analysed “Reducing railway noise pollution”. Instead, source-driven measures reduce noise across the whole railway system, if they are widely introduced.
Also, wheel suspensions, the aerodyna-mic form of pantographs and phonic isolation of traction equipment (for example, the locomotive engines) are measures to reduce source noise.
In the authors’ opinion, noise should ideally be reduced at the source because these measures have a network-wide effect. Where track infrastructure causes increased noise levels (for example, structure-radiated noise from viaducts or curve squeal in narrow radius curves), or where the local environment is particularly sensitive to noise (for example, rural or urban environments with residences very close to the railway line) then additional trackside noise mitigation measures may be necessary. Such measures include friction modifiers, rail dampers, and floating (or isolated) slab tracks and of course noise bunds and barriers in various heights. Vehicles and track should all be maintained to eliminate unnecessary sources of noise, for example, corrugation. On the infrastructure side, friction modifiers, rail dampers and slab track are cost-effective measures for reducing noise. In densely populated environments and highly trafficked railway sections, the use of noise barriers or coverings cannot be avoided. However, if there is a wide introduction of vehicle-related measures, the number of noise barriers or covers can shrink significantly. Without doubt, economic facilities, such as rail charging differentiated according to noise emissions, can help stimulate the use of technologies with low noise emissions for rolling stock.
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