The Land Transport Authority (LTA) awarded the third and final phase of its Railway Noise Barrier Programme - which began in 2013 to install noise barriers along MRT viaducts - to PBT Engineering yesterday.
The company will build noise barriers along a 5.5km stretch at 16 locations, running from Jurong East to Khatib on the North-South Line (NSL), and from Pasir Ris to Kembangan on the East-West Line (EWL). The project is to be completed in 2023.
With all three phases of the programme completed, there will be 27km of noise barriers at 61 locations on the NSL and EWL, said Transport Minister Khaw Boon Wan, who was at Cheng San to observe how effective such barriers had been.
"LTA will continue to monitor the effectiveness of these noise barriers after implementation," the minister added.
The LTA said that when completed, the noise barriers are expected to reduce railway noise levels by five to 10 decibels.
During a demonstration of MRT noise levels to Mr Khaw, Dr Xu Jing Feng, principal consultant of Arup Singapore, which is the technical consultant company hired by PBT Engineering, said that a three decibels difference would be noticeable for adults.
He added: "Five decibels is a significant difference, and achieving a 10 decibel difference would be halving the noise created by the passing MRT."
There are two types of noise barriers installed under the Railway Noise Barrier Programme, depending on the noise level and the type of train tracks.
For example, noise barriers installed at turnout sections - where trains switch tracks - have a semi-enclosed "portal" design to handle the higher noise levels, while the plainline noise barriers are vertical.
The portal design is being built in the stretch of railway tracks between the Yio Chu Kang and Ang Mo Kio stations on the NSL as part of the second phase of the programme.
Private tutor Steven Toh, 52, has lived for more than 30 years on the 10th floor of an Ang Mo Kio flat along this stretch where the noise barriers are being built. He said: "When the train passes by, we can't hear the TV or each other.
"The construction (of the noise barriers) and the track maintenance are very loud and take place past midnight, sometimes even at 4am we can hear it."
Ms Jane Tay, 55, a part-time worker who has lived in Ang Mo Kio for 28 years, added: "It feels a lot quieter, but actually we have lived here for so long that we are already used to it."