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Bonatrans noise absorbers |
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Railway transport is known to have lower environmental impact compared with road transport. Nevertheless, there are also effects on the environment that have to be solved. This includes especially the issue of noise, which is paid great attention.
One of four primary rolling stock noise sources is the noise that is generated during rolling of wheel on the rail. And this is exactly the noise source the Bonatrans research department focuses on. These activities lead to implementation of several wheel noise and vibration (generated by the wheel rolling) absorbing systems.
A. Noise absorbing rings
Rings represent financially undemanding method of noise supression. They offer low weight and purchase price, however, their suppression effect is lower and their service life is limited to the service life of the wheel. They are used in cases where lower absorption suffices to meet the noise limit.
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Noise absorbing rings
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B. Composite absorbersComposite noise and vibration absorbers consist of a combination of several various material layers that are selected for maximum suppression of vibrations for a particular wheel type. Currently, the suppression effect reaches a quality level of up to 5dB(A) for rolling noise, up to 30 dB(A) for screeching noise, and further research is ongoing with the aim of improving these values. The service life of this absorber is higher compared with the ring, since it is not limited to the wheel service life. Low weight (up to 10 kg), possibility of application to all wheel types and simple and reliable method of fixation to the wheel predetermione this absorber for wide utilization.
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Composite absorbers
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Noise measurement in MBTA metro, Boston, MA, USA
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