Track maintenance is an important aspect of SMRT’s rail operations, and it is done daily to ensure commuters can enjoy a safe and comfortable ride in our network.

In the last few years, we have significantly increased the number of train trips to meet commuters’ demand for higher train frequency. This also means we have to step up track maintenance activities. However, we assure residents living in affected vicinities that every effort is made to minimise inconvenience.

To check if there are track maintenance activities in your district this week, please click here for the latest schedule.

TRACK MAINTENANCE PROGRAMME

SMRT’s MRT network consists of 257.8km of tracks, covering the North-South, East-West (NSEW) and Circle lines. About 74 per cent of tracks on the NSEW lines are above ground level, which means there is noise involved in maintenance works due to heavy machinery used.

Tracks can only be maintained after passenger service hours. Any maintenance during passenger service hours will disrupt service and inconvenience commuters. When the train network closes, our maintenance staff have less than four hours (between 1am and 4.30am) to complete these works.

Activities such as rail grinding and rail replacement involve heavy machinery, hammering, cutting and/or joining rails with use of a generator to provide power. Occasionally, we employ a Tunnel Ventilation Fan to provide ventilation for tunnel work. All these activities can cause considerable noise.

What is SMRT doing to minimise track noise?

We do a couple of things, mostly in preventive maintenance. In wheel profiling, we grind the wheels daily to maintain an even roundness and diameter for each wheel to allow the trains to travel smoothly and with less noise. Train wheels are also mounted with sound absorbers to reduce screeching sounds.

One of the biggest culprits of track noise is uneven track surface. To rectify this, we use a Rail Grinding Vehicle to grind track surface for smoother and less noisy train operations. Typically, a section of a track is ground every six to 12 months.

Track defects can also lead to noise, so our staff inspect the tracks everyday. To do this more efficiently, we invested in a high-tech automatic track inspection system called Rail Vision, which has a camera mounted on the undercarriage of trains. This way, we can spot any defects such as uneven track surface during passenger service hours.

Are noise levels in line with national guidelines?

Yes. SMRT has worked with the Land Transport Authority to establish a monitoring system to measure the noise generated by trains at selected locations close to major residential estates every three months. With these results, we can identify locations where the noise levels are close to the guidelines, and prioritise preventive maintenance works at these locations to ensure these guidelines are not breached.

Why is it still noisy after track maintenance?

Immediately after track grinding, the initial noise level may become louder as the new grinding marks on the track surface takes a while to smoothen out. To reduce inconvenience to residents living around the area, SMRT tries to schedule track grinding in both directions along particular sections within a couple of days.

As part of the plan to address railway noise, the Land Transport Authority will embark on a noise measurement study along the entire length of all elevated MRT tracks island-wide, which will cover more than 500 blocks of flats located close to elevated viaducts or turnouts. Please click here for details.