In 2010, Poznan Public Transport Operator (Poland) carried out a tram rail grinding campaign on certain sections of the network aimed at reducing the noise caused by the traffic of trams and at increasing the comfort of tram transport.
A study on the life quality in Poznan carried out by local researchers and demanded by the Local Council has revealed that more than 60% of the citizens complain about noise. The admitted noise level in the city centre and adjacent districts in the middle of the day is of 65 dB (55 dB at night). However, this level is many times exceeded especially by older trams that operate on rolling tracks which have not been recently repaired. Researchers from the Acoustic Research Centre of the Adam Mickiewicz University in Poznan have studied the noise generated by trams. The outcome of their study has showed that, in the city centre, the noise generated by trams varies between 70-75 dB and even higher on some streets. The project and its positive results have been described by Eltis.
Therefore, Poznan Transport Company has decided to reduce noise by grinding the rails. This procedure consisting in the grinding of the rail waving, more precisely, the levelling up of the waving which appear during the operation of the line and reducing the noise caused by the wheel-rail contact.
For the development of this operation a special device was imported (at that time, there was no such equipment in Poland) and used on the rail sections considered to be the noisiest. The grinding of a 1-km section can thus be operated in four hours. The noisy sections have been previously established after measurement operations.
Overall, more than 13 km of rails have been grinded at a cost of EUR 250 per 30 m of rail. The total cost of the entire
operation which took two weeks to complete amounted to EUR 100,000.
Until the development of this operation, Poznan Public Transport Operator has used different other instruments to reduce noise such as sound-absorbing instruments, rubber plates and elastic buffers to eliminate vibrations. The limitation of the tram speed has also been introduced which resulted in a 10 dB reduction of the generated noise. However, there have been various unpleasant consequences such as higher travel times and higher energy consumption.
But the rail grinding has not only contri-buted to reducing the noise caused by trams in the urban areas, it has also improved the comfort of tram travelling as it would no longer “balance” at different level areas.
As a result, more cities in Poland have adopted the method of rail grinding for reducing noise in the city, such as Torun and Krakow.
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