Circle Line
C830 trainset atStadium station.
Overview
Native name	Malay:Laluan MRT Circle Chinese:地铁环线 Tamil:இணைப்பு எம்ஆர்டி வழி
Status	Operational Under construction (Stage 6)
Owner	Land Transport Authority
Locale	Singapore
Termini	Dhoby Ghaut Stadium[a] Prince Edward Road (From 2026, during peak hours) HarbourFront (Until 2026) Marina Bay (Until 2026)
Stations	30 (operational) 3 (under construction)
Color on map	Orange (#fa9e0d)
Service
Type	Rapid transit Light metro
System	Mass Rapid Transit (Singapore)
Services	3
Operator(s)	SMRT Trains Ltd (SMRT Corporation)
Depot(s)	Kim Chuan
Rolling stock	Alstom Metropolis C830 Alstom Metropolis C830C Alstom Metropolis C851E (Future)
Daily ridership	450,000 (2023)[1]
History
Planned opening	1H 2026 (Stage 6)
Opened	28 May 2009; 16 years ago (2009-05-28) (Stage 3) 17 April 2010; 15 years ago (2010-04-17) (Stages 1 and 2) 8 October 2011; 14 years ago (2011-10-08) (Stages 4 and 5) 14 January 2012; 13 years ago (2012-01-14) (Circle Line Extension)
Technical
Line length	35.5 km (22.1 mi) (Operational) 4 km (2.5 mi) (Under Construction)
Track length	35.5 km (22.1 mi) (Operational) 4 km (2.5 mi) (Under Construction)
Character	Fully underground
Track gauge	1,435 mm (4 ft 8+1⁄2 in)standard gauge
Electrification	750 V DC third rail
Operating speed	limit of 78 km/h (48 mph)[2]
Route diagram Legend  CC16  Marymount ■ North–South Line toJurong East  NS17  Bishan  CC15  Thomson–E.C. Line toWoodlands North ■ Kallang River  CC17  TE9  Caldecott Central Expressway Lorong Chuan  CC14  Bukit Brown (future station) Serangoon  CC13  Pan Island Expressway ■ North East Line toPunggol Coast  NE12   DT9  ← toBukit Panjang toExpo → ■ Bartley  CC12   CC19  Botanic Gardens Kim Chuan Depot  CC20  Farrer Road Tai Seng  CC11   CC21  Holland Village Kallang–P.L. Expressway  EW21  East–West Line toTuas Link ■ ■ ← toBukit Panjang toExpo →  DT26   CC22  Buona Vista MacPherson  CC10   CC23  one-north Pan Island Expressway Ayer Rajah Expressway ■ East–West Line toPasir Ris  EW8   CC24  Kent Ridge Paya Lebar  CC9   CC25  Haw Par Villa Geylang River  CC26  Pasir Panjang Dakota  CC8   CC27  Labrador Park Mountbatten  CC7   CC28  Telok Blangah Stadium  CC6  Kallang Basin Nicoll Highway  CC5   NE1   CC29  HarbourFront  NE6  Dhoby Ghaut  CC1   NS24  Bras Basah  CC2   CC30  Keppel Esplanade  CC3  ■ Downtown Line toBukit Panjang Ayer Rajah Expressway Promenade  DT15  CC4   CC31  Cantonment Marina Reservoir Bayfront  DT16  CE1  ■ Downtown Line toExpo Marina Bay  NS27  CE2   CC32  Prince Edward Road ■ Thomson–E.C. Line toBayshore  TE20  ■ North–South Line toMarina South Pier This diagram: view talk edit

Interactive Map

TheCircle Line (CCL) is amedium-capacityMass Rapid Transit (MRT) line inSingapore. It runs in aloop fromDhoby Ghaut station in thecity-centre toHarbourFront station in the south viaBishan station in thecentre of the country. It also has a branch line fromPromenade station toMarina Bay station. Coloured orange on the rail map, the fully-underground line is approximately 35.5 kilometres (22.1 mi) long with 30 stations. Travelling from one end of the line to the other takes about an hour.

The line was the fourth MRT line to open on the network, with its first stage, fromBartley toMarymount, commencing operations on 28 May 2009. At launch, the line operatedAlstom Metropolis C830electric multiple unit (EMU) trains. The next stage toDhoby Ghaut opened on 17 April 2010, followed by the extension toHarbourFront on 8 October 2011. A two-station extension toMarina Bay was inaugurated on 14 January 2012. The final stage, running from HarbourFront to Marina Bay with stations atKeppel,Cantonment andPrince Edward Road, is scheduled for completion in 2026, at which point the line will form a complete loop.

It is the second line in Singapore after theNorth East Line to becompletely automated and driverless and is among theworld's longest driverlessrapid transit lines.^[3] The Circle Line was Singapore's first medium-capacity rail line. Ridership exceeded projections for its three-car trains, resulting in overcrowding compared with higher-capacity MRT lines. Following the line's opening, additional trains, including theC830C andC851E, were procured to accommodate growing demand.

The Circle Line dates back to 1989, when then-Minister for Communications and Information,Yeo Ning Hong, stated that such a system would be "feasible when the population reaches four million", noting the slow population growth and demand.^[4]

Feasibility studies for the proposed line commenced on 11 October 1994.^{[citation needed]} The line, then named the Marina Line, was first announced on 16 October 1997. The line would serve Marina Centre and the new downtown at Marina South, with multiple branches toChinatown and Dhoby Ghaut via theNational Stadium to eitherKallang orPaya Lebar stations. The line was planned to have 18 stations, with a possible extension toTanjong Pagar station.^[5] Plans for the line were confirmed and approved by the government on 12 June 1998.^[6] However, due to the high costs and lack of development in Marina South, the Chinatown branch was later removed in November 1999 and the line was reduced to 6 stations from the Dhoby Ghaut toStadium stations.^[7][8][9] A part of the removed leg later became part of theDowntown Line.^[10] On the other hand, a further extension towards Upper Paya Lebar was announced on 28 April 2001.^[11]

The Marina Line was eventually merged with a plannedLight Rail Transit line that went from Paya Lebar toBuona Vista viaSerangoon andBishan to form Circle Line Stage 3 on 20 January 2003,^[12] and subsequently Circle Line Stage 4 and 5 on 12 December 2003 when Stage 4 was extended from Buona Vista toWorld Trade Centre to close up the link and to provide connectivity from the west to Sentosa, becoming the Circle Line.^[13][14] On 8 August 2001,SMRT won the bid and was appointed the operator of the Circle Line.^[15] Names for the stations for the first three stages of the Circle Line were finalised in July 2005 after theLand Transport Authority (LTA) conducted apublic consultation exercise on the naming of stations.^[16][17] In November 2005, the names of the stations in Stages 4 and 5 were finalised.^[18][19][20]

Construction started on 13 March 2002 for Stage 1, 5 September 2002 for Stage 2, May 2003 for Stage 3, and January 2005 for Stages 4 and 5. Initially planned to be opened in stages from 2006 to 2010, at an estimated cost of S$6.7 billion, theNicoll Highway collapse delayed the opening of the first stage to 2009. When the line fully opened on 8 October 2011, the cost of construction had risen to nearly S$10 billion.^[21][22] Due to the collapse, the station was relocated to a new site two-thirds the size of the original 100 metres (330 ft) away.^[23] Three stations on the Circle Line were initially designed as 'shell stations', but the decision was made to open two of them, Caldecott and Haw Par Villa (previously Thomson and West Coast respectively), leavingBukit Brown as the only unopened station on the line.^[21]

The first section of the line, Stage 3, a 5 kilometres (3.1 mi) five-station segment stretching from Bartley to Marymount, opened on 28 May 2009.^[24][25] Initial ridership on this section was lower than estimated, at 32,000 passengers per day (ppd) instead of the estimated 55,000 ppd.^[26] Tunneling works for the entire line were completed on 17 August 2009.^[27] Stages 1 and 2 started operations on 17 April 2010,^[28][29] followed by Stages 4 and 5 (from theMarymount to HarbourFront stations) on 8 October 2011.^{[30][31][32][33]} A two-station extension to Marina Bay opened on 14 January 2012.^{[34][35][36][37]}

On 17 January 2013, then-Minister for Transport,Lui Tuck Yew, announced Circle Line Stage 6 which would "close the circle", set to be completed by 2025.^[38] The 4 km extension will run betweenMarina Bay andHarbourFront.^[39][40] The extension will connect commuters between the HarbourFront to Marina Bay stations and expand the rail network to the southern edge of the Central Business District. On 29 October 2015, LTA announced the station locations for Stage 6, with the working names of the stations beingKeppel,Cantonment, andPrince Edward. Tenders were called for construction between 2016 and 2017.^[41][42][43]

On 15 May 2017, the LTA invited the public to send in suggestions for names of the three MRT stations or propose to keep their current names.^[44][45] The Keppel and Cantonment stations kept their names, while Prince Edward station was changed to Prince Edward Road station.^[46]

Construction of Stage 6 commenced in late 2017. Ajoint venture – byChina State Construction Engineering (The Singapore branch) and Nishimatsu Construction – won the contract to build the new Keppel station and its associated tunnels.^[47][48]

Stage 6 of the line is now expected to be completed by 2026 instead due to delays caused by theCOVID-19 pandemic.^[49] Tunnelling works for the CCL6 were completed on 12 January 2022, with a final tunnel breakthrough from Prince Edward Road station into Cantonment station.^[50] The tunnels between Cantonment station and the adjacent Prince Edward Road station were constructed only 6.7 metres (22 ft) below the formerTanjong Pagar Railway Station. Prior to the tunnelling works, an extensive survey was conducted to ensure that the tunnels do not cross through the building's foundations. Structures were erected to protect the railway station's facade and interior, and monitoring instruments were installed to watch out for any building settlement.^[51] To construct the tunnels to Keppel station, the Keppel viaduct had to be closely monitored while underpinning the viaduct with new micro piles. Three bored piles were removed for the tunnelling works.^[52]

On 6 December 2024, it was announced that Stage 6 will commence operation in the first half of 2026. During peak hours, trains will no longer terminate at either Pasir Panjang or Paya Lebar except for withdrawal trains; instead it will run from Dhoby Ghaut to Prince Edward Road. During off-peak hours, trains will only run up to Stadium, and the full loop will run all day (known as clockwise loop or counter-clockwise loop).^[53]

On 20 April 2004, a section of the tunnel being built for the Circle Line collapsed, when aretaining wall used in the tunnel's construction gave way. This incident occurred near the proposed site of the Nicoll Highway station, not far from theMerdeka Bridge. The accident left a collapse zone that was 150 metres (490 ft) wide, 100 metres (330 ft) long, and 30 metres (98 ft) deep. Four workers were killed, and three were injured.^[54]

A criminal inquiry found the main contractor Nishimatsu Construction Company and joint venture partner firm Lum Chang Construction Company and their officers, as well as keyLand Transport Authority officers responsible for the collapse. Several other officers andsubcontractors were reprimanded and issued warnings in connection with the accident.^[54]

As a result of this accident, the first phase of the Circle Line, previously scheduled to open in 2008, was completed in 2009 instead. The affected station has been shifted about 100 metres (330 ft) away from the accident site and is now located at Republic Avenue.

This accident also resulted in stricter safety regulations for the construction of all future MRT lines. The shifting of the Nicoll Highway station also meant it can no longer serve as a terminus for the Bukit Timah Line, partially influencing the creation of the currentDowntown Line.^[55]

On 16 August 2007, theBuilding and Construction Authority (BCA) issued a stop-work order and revoked the contractor's tunnelling permit after a 7-metre (23 ft) stretch of two lanes close to the junction of Telok Blangah Road and Alexandra Road sank about 20 centimetres (7.9 in) that evening.^[56]

A section of the road above a construction site nearHolland Road caved in on the morning of 24 May 2008, creating a hole. The hole, directly in front of two private houses along Cornwall Gardens, measured 8 by 7 metres and was 3 metres deep. No one was injured, but the road was temporarily closed to traffic.^[57]

On 20 September 2011, a power fault disrupted train services at all 16 stations on the Circle Line. The four-hour delay left thousands of commuters stranded during rush-hour. It was reported thatleaks and a damagedelectrical cable along the Circle Line were the cause of the disruption.^[58] The disruption started at about 5.30am. Train services were gradually restored from 8am and all services were restored just before 10am.Dakota andMountbatten stations were the last two to resume operations.^[59] Investigations were carried out, and the fault was traced back to a faulty cable beneath the platform level at Dakota station.^[60] 27,000 passengers were affected by the disruption during the four hour delay, with bus bridging services plying the Circle Line route.^[61]

In late August 2016, intermittent signal interference led to a five-day series of train disruptions. The issue reappeared in November.^[62][63] A team ofdata scientists explored the data and discovered via aMareychart visualization that it was caused by hardware problems, sending errant signals from a "rogue" train, PV46.^[64]

On 30 September 2023, due to the discovery of a crack on the rails near Promenade station, delays of about 30 minutes occurred between Dhoby Ghaut, Marina Bay, and Stadium stations for 14 hours.^[65]

On 17 September 2024, at 5.50pm, a power outage on the Circle Line disrupted services along the entire line, with 11 trains stalled in the tunnels. Power was restored by 6.05pm, and SMRT staff had to manually drive the stalled trains to their next stations, causing delays of about 30 minutes,. Normal train services fully resumed by 7.40pm.^[66][67] Investigations show that the disruption was first caused by a circuit breaker that tripped in the Traction Safety Shutdown System (TSSS) cubicle. After SMRT's maintenance team reset the circuit breaker, they had concerns that the fault might reoccur and decided to replace the main circuit breaker that had also tripped. They powered down the TSSS cubicle as a safety precaution, but caused another circuit breaker to trip, which led to the loss of power on the entire line. The maintenance team had failed to seek clearance from the head of CCL operations before proceeding with the maintenance, and such maintenance work should have been done during engineering hours while trains were not running.^[68]

On 18 September 2024, at around 8pm, a fire in the Traction Safety Shutdown System (TSSS) cubicle was detected, triggering a power shutdown along the entire line as part of a safety feature. This comes one day after a power fault that affected the entire line as well. The fire was extinguished, and traction power was restored within 10 minutes. Full train services resumed at 8.15pm. After the incident, SMRT said that the procurement of a replacement TSSS cubicle with enhanced features, is being expedited. Systemic improvements will also be made, including enhancements to the Circle Line's signalling and PA systems, as well as fail-safe and fail-soft features.^[68]

The Circle Line is the second line in Singapore to becompletely automated and driverless, following theNorth East Line, and is among the world's longest driverlessrapid transit lines.^[3] It is also the firstmedium capacity line in Singapore.^[69]

In 2011, the Circle Line was projected to reach a final ridership of 400,000 passengers per day upon full completion.^[70] However, the line quickly surpassed expectations due to population growth and rising commuter demand, with reports of overcrowding emerging as early as October 2011 when Stages 4 and 5 opened.^[71] By May 2015, daily ridership had reached 398,000,^[72] and by 2023, the line averaged over 450,000 passengers per day.^[1]

Key interchanges such as inSerangoon andBishan in particular have frequently experienced overcrowding especially during peak hours due to the stations' narrow platforms and the operational constraint of running only three-car trains.^[73] Commuters have reported waiting times of up to 30 minutes during peak hours to board a train.^[74] In response, the LTA has announced that 23 new trains will be added to the line in 2026 to further reduceheadway.^[75]

The 35.5-kilometre (22.1-mile) Circle Line forms an incomplete loop fromDhoby Ghaut in theCentral Region of Singapore, north toSerangoon andBishan, and south toHarbourFront, with a branch fromPromenade toMarina Bay station which will be extended to HarbourFront in 2026. The fully-underground circular route also makes several links with the other MRT lines.^[69] The line begins at Dhoby Ghaut station, which has an interchange with theNorth–South Line andNorth East Line, going eastwards and parallelingBras Basah Road and Raffles Boulevard, before joining the Circle Line extension at Promenade station, which also interchanges with theDowntown Line. From Promenade station, the line goes northwards and towards the east, passing beneath theKallang Basin. Between theStadium andDakota stations, the line parallels Stadium Boulevard andOld Airport Road, then the line continues northwards and follows the route of Paya Lebar Road and Upper Paya Lebar Road between thePaya Lebar (which interchanges with theEast–West Line) andTai Seng stations.

The line curves and continues westwards between theBartley andMarymount stations, also interchanging with the North East and North–South lines atSerangoon andBishan stations respectively, and then it continues in a general southwest direction betweenCaldecott andKent Ridge, the former having an interchange with theThomson–East Coast Line, passing throughBukit Brown Cemetery between the Caldecott andBotanic Gardens stations. The line also interchanges with the Downtown Line atBotanic Gardens station and the East–West Line atBuona Vista station. After Kent Ridge station, the line curves eastwards, paralleling theWest Coast Highway and then terminating at HarbourFront station, where it interchanges with theNorth East Line.

From 2026, upon the completion of Stage 6, the Circle Line will continue eastwards from HarbourFront, paralleling Keppel Road andAyer Rajah Expressway, and joins the Circle Line extension at Marina Bay station. The Circle Line extension from Marina Bay to Promenade station generally parallels the Downtown Line and Bayfront Avenue, also passing underneathMarina Bay Sands atBayfront station, which it serves and hascross-platform interchange with the Downtown Line. Also, end-destination number 8 and 9 will be replaced by clockwise and counter-clockwise loops.

Station codes for the line are orange, corresponding to the line's colour on the system map.^[77] All stations have island platforms, with the exception ofPromenade and future infill stationBukit Brown.

Legend

Elevated	Lineterminus	Transfer outsidepaid area
Ground-level	Wheelchair accessible	Bus interchange
Underground	Civil DefenceShelter	Other transportation modes

List

Station code	Station name	Images	Interchange; Adjacent transportation	Opening	Cost
CC1  NS24  NE6	Dhoby Ghaut		North–South Line   North East Line	17 April 2010; 15 years ago	S$343.94 million [78][79][80][note 1][note 2]
CC2	Bras Basah		—
CC3	Esplanade
CC4  DT15	Promenade		Downtown Line  ― Marina Centre
CC5	Nicoll Highway		—		S$573 million [81][82][note 1][note 3]
CC6	Stadium
CC7	Mountbatten				S$322 million [83][84][85][86][note 4][note 5]
CC8	Dakota
CC9  EW8	Paya Lebar		East–West Line
CC10  DT26	MacPherson		Downtown Line		S$356.1 million [87][88][89][note 4][note 6]
CC11	Tai Seng		—
CC12	Bartley			28 May 2009; 16 years ago	S$63.5 million[90][91]
CC13  NE12	Serangoon		North East Line  ― Serangoon		S$155.95 million[92]
CC14	Lorong Chuan		—		S$65.0 million[93][94]
CC15  NS17	Bishan		North–South Line  ― Bishan		S$82.2 million[94][91][95]
CC16	Marymount		—		S$167.7 million
CC17  TE9	Caldecott		Thomson–East Coast Line	8 October 2011; 14 years ago	S$391.59 million [96][note 7][note 8]
CC18	Bukit Brown		—	TBA
CC19  DT9	Botanic Gardens		Downtown Line	8 October 2011; 14 years ago
CC20	Farrer Road		—
CC21	Holland Village				S$399.91 million [97][98][note 7][note 9]
CC22  EW21	Buona Vista		East–West Line  ― Buona Vista Ghim Moh
CC23	one-north		—
CC24  JE	Kent Ridge		Jurong Region Line (East)  (early 2040s)
CC25	Haw Par Villa		—		S$335 million [99][note 10][note 11]
CC26	Pasir Panjang
CC27	Labrador Park
CC28	Telok Blangah
CC29  NE1	HarbourFront		North East Line  ― HarbourFront
Stage 6 (under construction, to be ready by 1H 2026)
CC30	Keppel		—	1H 2026; 1 year's time	S$313.8 million [100][101][102][note 12]
CC31	Cantonment				S$205 million [103][104][105][note 13]
CC32	Prince Edward Road		Shenton Way		S$310.8 million [106][107][note 14]
Circle Line Extension
CE2  NS27  TE20	Marina Bay		North–South Line   Thomson–East Coast Line	14 January 2012; 13 years ago	S$348.4 million [108][109][110][note 15]
CE1  DT16	Bayfront		Downtown Line		S$463 million [note 16]
Continues onto CC4  DT15 Promenade.

The Circle Line's numbering scheme reserves station code "CC18" for future use.

Depot name; Lines	Location	Images	Line-specific stabling capacity	Cost	Opening
Kim Chuan	Hougang		70 trains (until 2026) 133 trains (from 2026)	S$1.507 billion[111][112][113][100][101][b]	4 March 2009; 16 years ago

Therolling stock for the Circle Line uses electric multiple unit (EMU) trains operating in a three-car configuration, with four doors per side on each carriage and can accommodate of up to 931 passengers in each trainsets.^[114] It consists of 40 first-generationAlstom Metropolis trains were supplied under contractC830.^[115][116] They are built inFrance byAlstom between 2006 and 2008.^[114] They are stabled atKim Chuan Depot, which was the world's largest underground depot when it opened in 2009.^[117] To increase the capacity of the Circle Line, an additional 24 second-generationAlstom Metropolis trains were supplied under contractC830C, a similar in design to the first-generation trains, were delivered to Singapore from July 2014.^[118][119] They are also built inShanghai,China byAlstom between 2014 and 2016.^[114] To facilitate the extension of the line with the construction of Stage 6, a tender for additional trains for the line was published on 31 March 2017.^[120] To increase the capacity of the Circle Line for Circle Line Stage 6, an additional 23 third-generationAlstom Metropolis trains were supplied under contractC851E with the first train set arrived in Singapore on 11 March 2022.^[121]

The automated CBTC system on board relies on "continuous two-way digital communication" between each controlled train and the control centre.

The Circle Line is equipped withAlstom Urbalis 300Communications-based train control (CBTC)moving block signalling system on the MASTRIA system withAutomatic train control (ATC) underAutomatic train operation (ATO) GoA 4 (UTO).^[122][123] The subsystems consist ofAutomatic train protection (ATP) to govern train speed, Iconis Automatic Train Supervision (ATS) to track and schedule trains and SmartlockComputer-based interlocking (CBI) system that prevents incorrect signal and track points to be set.

Train Data Management System (TDMS) which concentrate and dispatch the rolling stock information with fixed equipment. The IAGO Waveguide communications network has the capability to transmit video and is almost maintenance-free. Base stations are located within the signalling equipment room.

Automaticplatform screen doors supplied byWestinghouse provide safety for commuters, offering protection from arriving and departing trains.^[124]

• Media related toCircle MRT line at Wikimedia Commons
• Circle Line
• LTA's commemorative book detailing the construction of the Circle Line

• Mass Rapid Transit (Singapore) lines
• Railway lines opened in 2009
• Railway loop lines
• 2009 establishments in Singapore

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