The Circle Line (CCL) is a rail line on the Singapore Mass Rapid Transit (MRT) system. Operated by SMRT Trains, it runs in a loop mostly within the Central Region of the country, with a spur running from Dhoby Ghaut to Promenade. Coloured orange on the rail map, the fully underground line is long with 33 stations.
The CCL was initially conceived in the 1990s as the Marina Line, a light rail system linking the National Stadium, Shenton Way, and Marina South. An outer circle line, connecting and Paya Lebar via and , was also proposed. In April 2001, it was announced that the section of the Marina Line between Dhoby Ghaut and Stadium would be built as the first stage of the CCL, comprising a loop extending to Marina South via World Trade Centre. Work began in 2002, but the Nicoll Highway collapse delayed the expected completion date of CCL Stage 1 from 2007 to 2009.
Stage 3, which spans between Bartley and Marymount, opened on 28 May 2009. The completion of Stages 1 and 2 on 17 April 2010 extended the CCL to Dhoby Ghaut. The line was extended to HarbourFront on 8 October 2011 with the opening of Stages 4 and 5. A two-station extension to Marina Bay was inaugurated on 14 January 2012. Stage 6, the final section connecting HarbourFront and Marina Bay via Keppel, Cantonment and Prince Edward Road, opened on 12 July 2026.
The CCL is Singapore's first medium-capacity rail line, and utilises three types of Alstom rolling stockC830, C830C and C851Eall of which runs in a three-car formation. The line is fully automated and uses Alstom's Urbalis 300 Communications Based Train Control (CBTC) signalling system. Several artworks are displayed on all stations of the line as part of the Art in Transit programme.
History Planning
Plans for the Circle Line were first announced by Minister for Communications and Information Yeo Ning Hong, who said the line would connect Singapore's major housing estates. However, he added that such a route would only be built once Singapore's population reached four million and new housing estates were developed farther from the city centre. At the time, the MRT network followed a radial pattern, with lines extending outward from the city centre.
In October 1994, Communications Minister Mah Bow Tan announced a proposed overground light rail system designed to serve the National Stadium, Beach Road, Marina Centre, Shenton Way, and Marina South, with interchanges at and . In October 1997, the Land Transport Authority (LTA) invited companies to provide architectural and engineering services for a planned Marina Line (MRL). The proposed underground line would comprise 18 stations, running from Kallang station through Marina Centre and Marina South before interchanging with the North East Line at . A branch line from Marina Centre to Dhoby Ghaut was also proposed, while further branches and extensions to and were under consideration. In June 1998, Mah announced the government would proceed with the construction of the MRL, which was planned to have 20 stations and operate medium-capacity driverless trains. Construction was expected to begin in 2000 at an estimated cost of S$1.75 billion. The line was also designed with provisions to expand train capacity from four to six cars as passenger demand increased. Parsons Brinckerhoff and Mott MacDonald were appointed as architectural and engineering consultants for the MRL.
In October 1999, the LTA announced that an outer circle line would link and Paya Lebar via and . The number of planned stations on the MRL also increased to 24. Construction of the segment between Dhoby Ghaut and Marina Centre would be prioritised given demand along the Bras Basah corridor, while construction of the other sections would be deferred due to lack of developments in the planned Marina Downtown. In November, the first six stations of the MRL from Dhoby Ghaut to were announced, with plans to connect the MRL from Stadium station to the Outer Circle Line at Paya Lebar. The Outer Circle Line would also loop back to Marina South via World Trade Centre. Subsequently in April 2001, communications minister Yeo Cheow Tong announced that the Marina Line would be built as the first phase of the Circle Line (CCL), alongside the announcement of the second phase that would span from Stadium to Upper Paya Lebar Road.
Construction
+ Circle Line stations timeline Date Project Description 28 May 2009 Stage 3 (CCL3) Bartley – Marymount 17 April 2010 Stage 1 (CCL1) Dhoby Ghaut – StadiumStage 2 (CCL2)Mountbatten – Tai Seng 8 October 2011 Stage 4 (CCL4) Caldecott – Kent RidgeStage 5 (CCL5)Haw Par Villa – HarbourFront 14 January 2012 Circle Line Extension (CCLe) Bayfront – Marina Bay 12 July 2026 Stage 6 (CCL6) Keppel – Prince Edward Road Industry observers anticipated that Trans-Island Bus Services would operate the CCL in accordance with the Singapore Government's initiative for multi-modal operators. TIBS had partnered with for its bid to operate the line. However, the LTA ultimately awarded the contract to SMRT Corporation in August 2001. The LTA justified its decision based on SMRT's track record, financial strength, and customer service.
Construction of the CCL officially began on 5 March 2002 with a groundbreaking ceremony at Bras Basah Park. At the ceremony, Yeo announced that the CCL would be built in five stages and completed by 2010. Stage 3 of the CCL (CCL3), which comprises five stations from to , was announced in January 2003. The 13 stations of CCL Stages 4 and 5 (CCL4 and CCL5) from Thomson to were announced in December 2003. This segment included three planned shell stations – , and . These station were to be opened only when their surroundings were more developed.
On 20 April 2004, the tunnels linking to Nicoll Highway station caved in along with a stretch of the Nicoll Highway. The collapse of a tunnel retaining wall caused soil subsidence, creating a hole 100 metres long, 130 metres wide, and 30 metres deep (328 by 427 by 98 ft). Four people were killed and three were injured. The LTA halted work at 16 of the 24 CCL excavation sites for review. A Committee of Inquiry (COI) concluded that the incident was caused by human error and organisational failures. The strut-waler support system was poorly designed and weaker than it should have been, with a lack of monitoring and proper management of data. Although the LTA initially said that the collapse happened without warning, the COI report revealed that there were already "warning signs", such as excessive wall deflections and surging inclinometer readings, which were not addressed seriously. The report pointed out a lack of safety culture at the site and made several recommendations to improve the safety of construction projects, which the government accepted. Nicoll Highway station was rebuilt south of the original site along Republic Avenue, with a new tunnel alignment between the Millenia and Boulevard stations. Due to the tunnels' collapse, the completion date of CCL Stage 1 was delayed from 2007 to 2009.
In March 2004, the LTA launched a public polling exercise to name the stations along the CCL, marking the first time the general public was invited to participate in the naming process to foster a greater sense of community ownership. The public could choose between two LTA-proposed names for each station or suggest their own, provided the names accurately reflected the area's locality, history, and multi-cultural heritage. The names for the CCL Stages 1 to 3 stations were finalised in July 2005. A subsequent naming poll for the CCL4 and CCL5 stations attracted 634 respondents – 152 more than the previous poll. These station names were finalised in December 2005.
On 14 June 2005, the LTA announced plans for the Downtown Extension (DTE), which was intended to be a branch of the CCL. Comprising five stations from Milennia (now Promenade) to Chinatown, it would serve the development of the Downtown at Marina Bay, a planned business and financial hub. Yam Ah Mee, the then-chief executive of the LTA, also stated that the agency was studying further extensions to the DTE, including an eastward extension to Kim Chuan Depot and a westward extension linking the line to the Bukit Timah Line In 2007, transport minister Raymond Lim announced that the DTE would instead be incorporated into the Downtown Line (DTL). Another branch to Marina Bay station via Bayfront was announced in April that year.
Construction of the CCL platforms at Dhoby Ghaut required stabilising the existing underpass above linking the North East Line (NEL) and North–South Line platforms. Seven caisson piles were installed to enhance the support of the underpass and capping beams were then constructed to form the supporting system. At , the arterial routes of Bras Basah Road and Nicoll Highway had to be diverted through more than 10 phases. The station was constructed using the top-down method to minimise the impact of noise and dust pollution on the surrounding developments. Diaphragm walls were built to minimise ground movement. With the roof constructed first, construction could proceed under all weather conditions while allowing the early reinstatement of Bras Basah Road and War Memorial Park. Two East–West Line viaduct piers at Paya Lebar station had to be underpinned. Using concrete walls, beams, and a powerful jacking system, they transferred the weight of the viaduct so they could safely cut away the old piles.
During excavation of the CCL tunnels beneath Serangoon station, contractors encountered significant groundwater seepage, causing ground settlement and the NEL station to sink by . Works were suspended while water was pumped out, and NEL trains were required to slow when entering or leaving the station. The tunnel was subsequently redesigned, with jet grouting and enhanced monitoring introduced to detect further settlement. At , the excavation pit was only away from the Willyn Ville Condominium, requiring vigilant ground testing and wall deflection monitoring to ensure the building's safety. Similarly, was dug in soft ground just from a road viaduct and in close proximity to residential homes and shophouses.
Following the ground settlement of two road lanes near the junction of Telok Blangah Road and Alexandra Road in August 2007, the Building and Construction Authority halted tunnelling works near Telok Blangah. A section of Cornwall Gardens Road near Holland Road caved in on 24 May 2008 during tunnelling works between Holland and Farrer Road stations. While no one was injured, the sinkhole led to the disruptions of utilities in the area.
Opening The Straits Times reported that the CCL3 stations were "in advanced stages of completion" in September 2007, with architectural, engineering, and mechanical works being carried out and expected to be finished by mid-2008. In January 2008, the CCL3 stations' completion date was moved earlier from 2010 to mid-2009. Two of the planned shell stations – Thomson and West Coast – would also be fitted out and opened with the other CCL stations. The LTA started conducting test runs on the CCL3 stations, with the expected commencement date set for June 2009. In February 2009, transport minister Raymond Lim announced that CCL3 would open on 30 May, though it was later moved to 28 May. An open house was held for the CCL3 stations on 23 May, before operations commenced on 28 May. An opening ceremony was held at Bishan station, presided by deputy prime minister Teo Chee Hean.
Due to the Nicoll Highway collapse, the expected opening date for CCL1 was delayed by two years from 2007 to 2009. In August 2009, transport minister Lim announced that CCL1 and 2 would open by the first half of 2010; this was later announced to be 17 April. An open house was held on 5 April 2010. CCL1 and CCL2 commenced operations on 17 April 2010, with transport minister Lim holding an opening ceremony at Bras Basah station the day before.