Longer travelling times at 7 Circle Line stations from June 11 over 6 weeks to facilitate tunnel works: LTA

SINGAPORE — Commuters can expect longer travelling times at seven Circle Line stations during a six-week period in June and July as train services will be adjusted to facilitate maintenance works, the Land Transport Authority (LTA) said on Wednesday (May 24).

The list of affected stations are:

• Dhoby Ghaut
• Bras Basah
• Esplanade
• Promenade
• Nicoll Highway
• Marina Bay
• Bayfront

In a press statement on Wednesday, LTA said it found that a small segment of the Circle Line tunnel between Promenade and Nicoll Highway stations has been subject to “greater pressure” during its routine inspection with public transport operators.

It added that this poses no safety risks to train operations on the line.

“Nonetheless, LTA will carry out precautionary maintenance and strengthening works including installation of steel supports to the tunnel rings to ensure the long-term integrity of the tunnel.

“LTA and the operators will continue to regularly monitor tunnels used for rail operations as part of our maintenance regime,” it said.

In response to TODAY's queries, the authority said that it had set up monitoring instruments in this segment of the Circle Line tunnel to measure "tunnel movement levels" around the clock to ensure that they were within safe levels.

"All the tunnels are made with reinforced concrete segments. When the tunnels were originally constructed, the ground conditions were taken into account in designing the tunnels." 

In response to a "localised incidence of higher-than-projected ground pressure", it will be installing new steel plates as an "additional strengthening measure", it added.

It also said that residual ground settlement or movement is common, and "some settlement is still expected for some time" after construction.

"This is why we closely monitor tunnel stretches located in reclaimed land consisting of marine clay, such as this Circle Line tunnel stretch, especially closely.

"At present, we have not detected a similar issue in other areas."

An engineering expert said that at this stage, there are no risks for commuters and operators as the proposed strengthening is a preventive precautionary measure.

"Greater pressure is result of ground settlement," said Mr David Ng, honorary secretary of the Institution of Engineers Singapore.

"The ground settlements in reclaimed land consisting of soft marine clay are expected, but due to varying ground conditions, the settlements could be beyond the expectation in the design. However, this does not pose safety risks to the structure"

On why there is a need for delays in travelling time while this problem is being rectified, he said that the proposed strengthening works require a longer time to complete. Thus, the usual normal engineering working hours are not enough to ensure the quality of works.

From June 11 to July 20, services at these Circle Line stations will operate on only one platform from 9pm daily, except for:

• June 16 to 18
• June 24
• June 28 to 29
• July 1 to 2
• July 7 to 8
• July 14 to 16

This will result in longer headways, and commuters will experience longer travel times of up to 30 minutes.

LTA advised commuters to plan their journeys ahead of time and use other rail lines or bus services to minimise inconvenience.

They may refer to LTA’s MyTransport.SG mobile application, and LTA and SMRT’s social media pages for more details.

LTA said that posters and station announcements will be rolled out at all Circle Line MRT stations and selected stations on alternate MRT lines that interchange with Circle Line stations.