At underground sections near high-rise buildings, tracks are laid on special floating slabs to cut down vibration and noise. At above-ground sections, the viaduct which supports the tracks is made of concrete with high mass and damping characteristics to minimise noise that may be induced to passing trains.
Measurements made after the trains started operating show that some areas along Ang Mo Kio Avenue 8 are noisier as a result of the MRT. At these areas, additional noise reduction measures can still be taken. The MRTC will be acquiring rail grinding machine to remove irregularities or corrugation of the rails. Flanges of the rail wheels will be automatically lubricated to reduce squealing when the trains negotiate sharp bends. A wheel lathe machine have also been procured which will be used to maintain the shape of the wheel at regular intervals so that they are smooth and therefore they do not produce noise.
My Ministry has conducted a noise survey in the area and we have found out that the ambient noise level measured in the HDB flats prior to the trains running was 67-75 dBA. With the trains now running, it became 80 - 85 dBA. The other housing estates which have flats closer to above-ground tracks are Yishun, flats in Bukit Merah, Queenstown, Clementi, Bukit Batok, Bedok, Simei and Tampines. But as in Ang Mo Kio, I do not expect the noise levels in these areas to be more than the traffic noise levels along the expressways.
As I indicated some months ago before the starting up of MRT system, we expect some teething problems for such a complex system. Most of the problems are equipment failures because of heavy or improper use. Others are due to the general public not being aware of ticketing machines, automatic gates, escalators and operation of trains. The problem with stored value card is 0.2%, misalignment of train doors is 0.1%, and train delays are 2.6%.
Since the MRT started in 1987, the Ministry have received eight complaints of noise from MRT trains. The SMRT, which operates the MRT system, dealt with complaints and took prompt actions to reduce the noise to permitted levels. With proper maintenance of the MRT system, we do not expect deterioration in noise levels and this has been the observation from the Ministry so far.