Railways are a significant cause of environmental noise pollution in Latvia and further afield. Increasing volumes of rail freight traffic and urbanisation are both having a negative impact. Moreover, surveys indicate that railways are the third most bothersome noise source and a cause of acoustic discomfort. Considering that cargo and passenger traffic circulates on rail 24-hours a day, sustained long-term exposure to noise may result in such health problems as sleep or central nervous system disorders, decrease in operational capacity, physiological and psychological disorders, and deviations in social behaviour. Noise can also have an negative impact on pets and wildlife. Data from a 2008 noise map of Riga showed that the emissions of noise created by rail infrastructure exceed the permitted noise level per day (Lday) in corresponding built-up areas on average by 5 dB(A) or 8%, and in some places the permitted noise level was exceeded by 15 dB(A) or 25%. At night, the permitted noise level (Lnight) from railways in corresponding built-up areas was exceeded by 10-15 dB (A) or 20-30%; in some places it exceeded 25 dB(A) or 50%.
The goal of the ISRNM project is to demonstrate a new means of reducing rail noise pollution and to adapt and apply the Dutch “Reken en Meetvoorschrift Railverkeerslawaai ‘96” (RMR) method for estimating noise from Europe's railways. The project will also test technologies for noise reduction and methods for protection against and reduction of rail noise. The technical activities of the project will be implemented in an urban environment, thus ensuring an acoustically favourable living environment for residents near rail lines in Riga.
Specific objectives are to:
- Establish the best material for the construction of noise walls as a result of modelling and acoustic tests. Simulations will be carried out using different configurations of the noise abatement walls. The project also foresees the creation of green (plant) noise barriers and will test the effect on noise levels of both the composite material and plant barrier; and
- Carry out investigations about the effectiveness of the RMR method in the mapping of rail noise, draft guidelines for adapting this method in a simplified way and propose improvements to the method, where required.
- Acoustic testing of a 1-km long noise abatement wall made from a new composite material;
- Acoustic testing of a 0.3-km long plant barrier for the abatement of rail-caused noise;
- An anticipated reduction of 10-20% in noise levels from railways as a result of the application of these methods. This will be confirmed through monitoring;
- Drafting of a noise action plan; and
- Evaluation of the effectiveness of the RMR noise assessment method; creation of new guidelines for simplifying the adaption of this method; and proposals for improvements to RMR.