In the last ten years there has been increasing pressure from residents, environmental lobbyists and legislators to reduce railway noise levels. In Switzerland, Austria and Italy (amongst other countries), legislation has been introduced that sets tight limits on the amount of noise railways are allowed to create (and inherently the traffic levels they can achieve). Anumber of Working Groups has been established by the EU's Environment Commission to determine the EU's future policy on potential noise legislation. Unless due consideration of all the factors (economic, technical, environmental) is taken into account, new legislation could have a potentially serious impact on rail transport and could particularly interfere with the environmentally encouraged growth of traffic from other sectors such as road and air. STAIRRS provides the relevant information needed for informed discussion and decision making and helps stimulate the debate required to ensure that a fair but effective solution is reached. There is little point introducing severe limits if they are not technically or economically achievable.
- To develop a decision support system to help Railway operators and infrastructure owners determine the most cost-effective spend needed to introduce an optimal blend of noise reduction measures as well as to help legislators gain a better idea of the potential cost of any proposed noise legislation.
- To look at measurement systems; to further develop and validate new measurement techniques such as vehicle/track separation and characterisation in order to help apportion 'noise responsibility' between operator and infrastructure owner.
- To create a forum for the project's technical experts and decision makers/policy initiators from outside the project, to discuss, and hopefully reach consensus, on the most appropriate way to manage the balance of environmental needs, technical feasibility and cost.
There are now a number of solutions which were used to allow some noise reduction to be achieved. It is necessary to ensure that the most cost effective and appropriate blend of those solutions is used. STAIRRS aims to facilitate this process through the development of a cost benefit decision support system for railway noise measures.
STAIRRS can assist the development of future low noise railways by providing tools for cost-benefit analysis to support the funding debate and by providing validated techniques for the separation of the wheel and track contribution to total rolling noise. A tool comprising noise prediction, cost - effectiveness analysis, extrapolation and optimisation modules has been successfully developed and tested.
- Composite brake blocks for freight rolling stock have the highest efficiency (effectiveness/cost) but provide insufficient benefit to meet potential future targets, for example the ERRAC 2020 noise reduction targets.
- Whenever the effect of smooth wheels is combined with other mitigation the effect is increased and the cost reduced.
- The highest benefits can be achieved with a solution combining k-blocks, optimised wheels, tuned rail absorbers, acoustic grinding and noise barriers no higher than 2 m.
- Track measures in combination with rolling stock measures give a good efficiency.
- Noise barriers, especially if barriers up to 4 m height are allowed, have a poor costeffectiveness.
- The costs for insulated windows are very high in situations with low benefits.
- Noise control at source is more effective than noise barriers
- Noise control is expensive. For the 21 countries studied, the total extrapolated present costs range from € 3.5 billion (k-blocks on freight wagons) to € 76 billion (allowing a maximum of four metre barriers). These prices increase if perpetual present costs are taken into account (including price of removal after the end of the lifetime and the replacement of the measure). There the maximum costs are € 109 billion.
- Money should be used to implement the most cost effective noise treatment even if this means reviewing funding regulations within the European Community.
- The major impetus for lower noise levels in the future would come from strict noise creation legislation for new vehicles and track. This may later be applied to existing vehicles and track. This legislation should be realistic and economically achievable.
- Noise mitigation by applying operational constraints (eg speed restrictions) was not compatible with the commercial competitiveness of railways, especially when the Commission’s policy is to transfer traffic from road to rail.