Dampers on track
Who: Corus Rail has developed a dynamic damper which reduces the noise generated by railway traffic by an average of 5 to 7dB(A).
Technology: The Silent Track technology came out of a European Union research project involving the Institute of Sound and Vibration Research at Southampton University which was aimed at reducing noise generated by railways.
The system employs patented “tuned dampers” comprising two resonant masses of steel embedded in elastomer with a high damping factor. The dampers are attached to either side of the rail with high-performance epoxy glues or spring clips. The dampers can be retrofitted to existing tracks in situ or pre-attached to new rail before it is delivered to site.
The tuned rail damper system effectively absorbs the vibrations from the rail-wheel interface and prevents noise from being generated by the rail. The energy of the movement is absorbed by the elastomer material, with the rail damper tuned to the frequency band with the highest noise level.
The system can be customised to suit typical or unique track configurations, making it ideal for tackling isolated noise hotspots, said Corus.
David Benton, product manager at Corus Rail, said that the system offered a wide-frequency response over the acoustic range for rail noise.
“The main difficulty in developing the damping system was to be able to reduce noise levels across the wide-frequency spectrum – ranging from around 600 hertz to several kilohertz. Rail noise is in the lower half of the range – up to around two kilohertz – and wheel noise is typically in the higher frequencies.”
Corus says the system is long-lasting and requires no maintenance. It has no effect on other elements of existing rail infrastructure and is visually unobtrusive. It also says it provides cost savings to network operators by eliminating or reducing the need for acoustic barriers.
Application: Around 16km of Silent Track has been installed on a new commuter route in the suburbs of Sydney, where almost 50,000 dampers were used. Several trials of the technology are being carried out in Sweden, Austria and Finland. In the UK, the technology was approved by Network Rail last summer and is being installed on the Thameslink upgrade in the South-east.
© PE Publishing, 27 January 2010
