Circle Line Tunnel Works 2026: Up to 30 Minutes Additional Waiting Time During Peak Hours

Commuters using the Circle Line (CCL) should prepare for significantly longer journey times during peak hours from January 17 to April 19, 2026, as the Land Transport Authority (LTA) conducts critical tunnel strengthening works affecting three stations. Additional waiting times of up to 30 minutes are expected during morning and evening peak periods at affected stations.

Major Service Adjustments

The works will affect the stretch between Mountbatten, Dakota, and Paya Lebar stations, where two parallel tunnels will be closed one at a time over the 93-day period. During the closures, affected stations will operate on a single platform, with shuttle trains running at 10-minute intervals—significantly longer than the usual 3-minute frequency.

This represents one of the longest scheduled service disruptions across Singapore's entire MRT network to date, impacting thousands of daily commuters who rely on this key stretch of the Circle Line.

Expected Delays Across the Line

The service adjustments will affect not just the directly impacted stations, but wider sections of the Circle Line:

• Mountbatten, Dakota, and Paya Lebar stations: Trains arrive at 10-minute intervals on a single platform (up from the usual 3 minutes)
• HarbourFront to Paya Lebar: Peak-hour waiting times increase to about 3 minutes, up from the current 2 minutes
• Mountbatten to Dhoby Ghaut or Marina Bay: Waiting times increase to about 10 minutes, from the current 6 minutes
• Interchange stations (Bishan, Serangoon, Buona Vista): Expected to be crowded during peak periods, with additional waiting time of up to 30 minutes compared to typical travel times

Shuttle Bus Services

To supplement the reduced train services, LTA will operate four dedicated shuttle bus routes during weekday peak periods:

• Shuttle Bus 38: Connects Paya Lebar and Stadium MRT stations, operating 6:30am-9:30am and 5pm-8pm at 6 to 10-minute intervals
• Shuttle Bus 37A: One-way service from Serangoon to Tai Seng, Macpherson, and Paya Lebar MRT stations, 7am-9am at 3 to 5-minute intervals
• Shuttle Bus 37B: One-way service from Tai Seng to Bishan MRT station, 5:30pm-7:30pm at 3 to 5-minute intervals
• Shuttle Bus 37C: One-way service from Tai Seng to Serangoon MRT station, 5:30pm-7:30pm at 3 to 5-minute intervals

Regular bus services that serve the affected areas remain available as alternatives throughout the day.

Why the Works Are Necessary

The tunnel strengthening works are required to address a phenomenon known as "tunnel squatting"—a gradual compression of soft marine clay through which the tunnels were built. Over time, this compression can cause circular tunnels to become more elliptical, potentially leading to structural defects and operational disruptions if left unaddressed.

LTA has been monitoring tunnel squatting for over a decade, with recent scans identifying three tunnel sectors between Stadium and Paya Lebar as being more significantly affected. While minor defects such as water leakage have been addressed through grouting, LTA decided to carry out these precautionary strengthening works to prevent more serious issues in the future.

"While we have addressed these issues, we decided to carry out precautionary strengthening works to reduce the risk of affecting rail services if left unaddressed," LTA stated.

The Engineering Challenge

The strengthening process involves installing steel plates along the circumference of affected tunnel segments, requiring heavy machinery, specialized lifting equipment, and coordinated engineering teams. More than 300 workers and engineers will be deployed within the tunnels to install these plates across 450 meters of tunnel segments.

Due to the scale and complexity of the works, LTA requires longer blocks of engineering hours to ensure safe and effective execution. To minimize the overall duration of service adjustments for commuters, the installation will be carried out 24/7 under a single, continuous tunnel closure.

Expert consultants have assessed that the remaining open tunnel is safe for train operations while works proceed in the adjacent tunnel, allowing services to continue on a single track.

Advice for Commuters

LTA strongly encourages commuters to plan ahead and consider alternative travel options during the affected period:

• Use alternative MRT lines: Where possible, avoid the affected sections of the CCL by taking other rail routes
• Adjust travel timing: Consider traveling outside peak hours (before 6:30am or after 9:30am for morning; before 5pm or after 8pm for evening)
• Take regular bus services: Regular bus routes serving the affected areas remain operational throughout the day
• Check real-time updates: Refer to LTA's MyTransport.SG mobile app and social media channels for the latest service information

LTA roadshows will be conducted at selected CCL stations and key transport nodes before the service adjustments begin. Posters and station announcements will be rolled out at all CCL and other MRT stations, and additional station staff will assist commuters, particularly seniors and those with mobility needs.

A Global Infrastructure Challenge

Tunnel squatting is not unique to Singapore. Cities with similar underground rail systems built on soft soil, including Shanghai, Taipei, Busan, Barcelona, and Lisbon, have experienced comparable issues and undertaken similar strengthening measures.

LTA noted that tunnel squatting results from geological processes and cannot be completely ruled out in the future. "We will continue to monitor the tunnel and ground to ensure they have stabilized even after works are completed," the authority stated.

Timing Ahead of Stage 6 Opening

The tunnel works are scheduled for completion ahead of Circle Line Stage 6's opening, which will finally close the Circle Line loop and provide greater connectivity across Singapore's rail network.

In November 2024, Acting Minister for Transport Jeffrey Siow noted that commuters should expect more planned closures of MRT lines as Singapore's rail network ages and requires extended maintenance time for major upgrades. The current approach of slightly extending maintenance hours by ending services earlier and starting later is no longer sufficient for the scope of works required.

This is not the first prolonged service adjustment for Circle Line tunnel works. Similar precautionary maintenance and strengthening works were carried out between Promenade and Nicoll Highway in June 2023, and between January and April 2024, platforms at Telok Blangah and HarbourFront were temporarily closed to integrate Stage 6 with the existing line.