The Circle line (CCL) is a medium-capacity Mass Rapid Transit line in Singapore. It runs from Dhoby Ghaut and Marina Bay in the Central Area to HarbourFront in the south, with the line between Marina Bay and Stadium operated as a shuttle service during off-peak hours. The line is 35.5 kilometres (22.1 mi) long with 30 stations, all of which are underground. Travelling from one end of the line to the other takes about one hour. It is the second in Singapore to be completely automated and driverless and is among the world's longest driverless rapid transit lines.. It is coloured orange (sofyouwin) on the rail map. The line is the fourth MRT line to be opened, with the first section having opened on 28 May 2009.
The Circle line is the first medium capacity line in Singapore. Each Circle line train has a three-car configuration. As of May 2015, the daily ridership is 398,000. The line reduces travelling time for commuters by shortening trips between northern, eastern and western Singapore, and bypassing busy interchange stations like City Hall and Raffles Place. It is the third MRT line to be operated by SMRT, after the North South line and the East West line.
As the name implies, the line is an orbital circle route linking all radial routes leading to the city. It also covers many parts of the Central Area. From Promenade, the line branches into two, with one branch terminating at Dhoby Ghaut, and the other at Marina Bay. The Circle line interchanges with all other Mass Rapid Transit lines within Singapore, such as the North South line and East West line.
Plans for the Circle line were laid out in the 1980s, when the then Minister for Communications and Information, Dr Yeo Ning Hong stated that such a system "would be feasible when the population reaches four million."
The Circle line was first named as the Marina line in May 1998, initially planned as a 12-station underground line, starting from Chinatown and Dhoby Ghaut via the National Stadium to either Kallang or Paya Lebar station. However, the Chinatown leg was later truncated and was reduced to 6 stations up to Stadium station. On the other hand, a further extension towards Upper Paya Lebar was added in the year 2000. The Marina line was also merged with an LRT line that goes from Paya Lebar to Buona Vista via Serangoon and Bishan to form Circle line Stage 3 and 4 in 2001. Circle line Stage 5 was finalised in February 2002 when Stage 4 was extended from Buona Vista to World Trade Centre to close up the link and to provide connectivity from the west to Sentosa, and it became the full Circle line in the end. Stations in Circle line that were a part of the original Marina line plans include Dhoby Ghaut, Bras Basah, Esplanade, Promenade, Nicoll Highway and Stadium. The part of the previously planned Marina line from Chinatown to Promenade is now part of the Downtown line.
Construction started on 13 March 2002 for Stage 1, 5 September 2002 for Stage 2, May 2003 for Stage 3, and January 2005 for Stage 4 -5, and the Circle line was supposed to be opened in stages from 2006 to 2010, with an estimated cost of S$6.7 billion, but the Nicoll Highway collapse caused the opening of the first stage to be delayed to 28 May 2009. When the line fully opened on 8 October 2011, the cost of construction had escalated to nearly S$10 billion. Due to the re-alignment of the Nicoll Highway station to a new location, the station is only two-thirds the size of the original plan before the collapse. It was located 100 metres (330 ft) away from the original site. Some stations on the Circle line were initially designed as 'shell stations', but the decision was made to open Caldecott and Haw Par Villa (previously Thomson and West Coast respectively), which leaves Bukit Brown as the only unopened station on the line.
Stage 3, a 5 kilometres (3.1 mi) five-station segment stretching from Bartley to Marymount, was the first section of the line opened, on May 28, 2009. Initial ridership on this section was lower than estimated, at 32,000 passengers per day (ppd) instead of the estimated 55,000 ppd. Tunneling works for the entire line were completed on August 17, 2009. Stages 1 and 2 started operations on April 17, 2010, Stages 4 and 5 on October 8, 2011, and the final Circle line Extension on January 14, 2012. The line was also fully completed in October 2011 to commemorate SMRT's 24th anniversary.
On 17 January 2013, the Land Transport Authority (LTA) announced 'Circle line Stage 6' which will finally 'close the circle'. This 4 km extension runs between Marina Bay and HarbourFront. This extension will connect commuters between HarbourFront to Marina Bay stations, and expand rail network to the southern edge of The Central Business District. On 29 October 2015, the LTA announced the station locations for Stage 6. The working names of the stations are Keppel, Cantonment and Prince Edward. Tenders were called for construction between 2016 and 2017 and demolition, diversion and utility works commenced in 2017. Construction of Stage 6 will begin earliest in 2018 and it is due for completion in 2025. When the three new stations are completed, the CCL will have a total of 33 stations.
On 15 May 2017, Land Transport Authority (LTA) invited the public to send in suggestions for names of the three new MRT stations. Their current working names are derived from their proximity to names of nearby locations. The public can also propose to keep their current names, which are Keppel, Cantonment and Prince Edward. The LTA also announced that construction on the Circle line Stage 6 was to commence on late 2017. LTA also said that a joint venture - by China State Construction Engineering (The Singapore branch) and Nishimatsu Construction - won the contract to build the new Keppel MRT station and its associated tunnels. The Tender proposals for the other CCL6 contracts, such as for the construction of the Prince Edward and Cantonment stations, are currently being evaluated. The contracts will be awarded and announced by the end of 2017.
On 20 April 2004, a section of the tunnel being built for the Circle line collapsed, when a retaining wall used in the tunnel's construction gave way. This incident occurred near the proposed site of the Nicoll Highway station, not far from the Merdeka 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, three were injured.
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 key Land Transport Authority officers responsible for the collapse. Several other officers and subcontractors were reprimanded and issued warnings in connection with the accident.
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 had 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 current Downtown line.
On 16 August 2007, the Building and Construction Authority (BCA) issued a stop-work order and revoked the contractor's tunnelling permit after a 7 metres (23 ft) stretch of two lanes sank about 20 centimetres (7.9 in), close to the junction of Telok Blangah Road and Alexandra Road in the evening, resulting in a halting of tunnelling works.
A section of the road above a construction site near Holland Road caved in on the morning of 24 May 2008, creating a massive hole. The hole, directly in front of two private houses along Cornwall Gardens Road, measured 8 by 7 metres and was 3 metres deep. No one was injured, but the road was temporarily closed to traffic.
On 20 September 2011, a power fault disrupted train services on all 16 stations on the Circle line. The four hours delay left thousands of commuters stranded during rush-hour. It was reported that leaks and a damaged electrical cable along the Circle line were the cause of the disruption. The disruption started at about 5.30 am. Train services were gradually restored from 8am and all services were restored just before 10am. Dakota and Mountbatten stations were the last two to resume operations. Investigations were carried out. It was later found that a faulty cable beneath the platform level at Dakota station caused a power fault on Tuesday morning that affected train services at all 16 stations on the Circle line. 27,000 passengers were affected by the disruption during the four hours delay, with bus bridging services plying the Circle line route.
In late August 2016, intermittent signal interference led to a five-day series of train disruptions. The issue reappeared in November. A team of data scientists explored the data and discovered via a Marey Chart visualization that it was caused by hardware problems, sending errant signals from a "rogue" train, PV46.
Circle MRT Line
|Station Number||Station Name||Images||Interchange/Notes|
|Dhoby Ghaut||Interchange with the North South line and the North East line|
|Promenade||Interchange with the Downtown line|
|Stadium||Marina Bay shuttle terminus during off-peak hours|
|Paya Lebar||Interchange with the East West line|
|MacPherson||Interchange with the Downtown line|
|Serangoon||Interchange with the North East line|
|Bishan||Interchange with the North South line|
|Caldecott||Interchange with the Thomson-East Coast line (2020)|
|Bukit Brown||Reserved station; Not in operation|
|Botanic Gardens||Interchange with the Downtown line|
|Buona Vista||Interchange with the East West line|
|Haw Par Villa|
|HarbourFront||Interchange with the North East line|
|Stage 6 (Under planning) (Completion by 2025)|
|Circle line Extension|
|Bayfront||Cross-platform interchange with the Downtown line|
|Marina Bay||Interchange with the North South line and the Thomson-East Coast line (2021)|
The Circle line's numbering scheme reserves station code "CC18" for future use.
The rolling stock consists of 40 Alstom Metropolis C830 trains running in three-car formation. They are stabled at Kim Chuan depot, the world's largest underground depot when it opened in 2009. 24 new Alstom Metropolis & Shanghai Electric C830C trains were delivered to SMRT from end July 2014. They began operation on 26 June 2015. Currently all 24 C830Cs are in revenue service.
The automated CBTC system on board relies on "continuous two-way digital communication" between each controlled train and the control centre.
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.
The Circle line is equipped with Alstom Urbalis 300 Communications-based train control (CBTC) moving block signalling system on the MASTRIA system with Automatic train control (ATC) under Automatic train operation (ATO) GoA 4 (UTO). The subsystems consist of Automatic train protection (ATP) to govern train speed, Iconis Automatic Train Supervision (ATS) to track and schedule trains and Smartlock Computer-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.