WHEN a train rushes past in the open air, the resulting din can be the equivalent of loud music blaring. Sound barriers, however, can bring it closer to the level of background noise in a supermarket.
So, about 20km of noise barriers will be erected across the island by 2020, to give people living near elevated MRT lines much-needed respite from passing trains.
The move, announced by Transport Minister Lui Tuck Yew yesterday, follows a year-long study of 455 Housing Board blocks near elevated open tracks. These include viaducts or turnout locations, where two lines merge so trains can be diverted from one to another.
The study found noise levels in these areas ranged from 80 to 85 decibels when a train passed by - the equivalent of loud music being played. This is above the National Environment Agency's limit of 67 decibels - comparable to noise in a supermarket.
During trials, barriers were erected in Bishan, Tampines, Jurong East and Toh Guan Road.
Mr Lui said they cut sound levels by between five and 10 decibels.
Residents welcomed the new project, which will cost $300 million. "I'm used to the noise, as I have been living near an MRT station all my life," said 21-year-old student Ooi Su Xin, whose home faces Marsiling MRT station. "But a new sound barrier would be great."
Retiree Peter Kok, 72, whose home is opposite the tracks in Bishan, said noise levels had fallen by about 30 per cent since sound barriers were installed last year.
The Land Transport Authority has said in the past that fitting barriers is complex as it can be done only during a three-hour period when trains are off-service.
Work also has to be coordinated with SMRT's ongoing resignalling and sleeper-replacement projects.
The authority is also testing noise reduction measures along roads with high traffic volumes, including the West Coast Highway viaduct in Telok Blangah Road.