View source for Circle MRT line

{{short description|Mass Rapid Transit line in Singapore}}
{{Hatnote|For other similarly named rapid transit lines in other countries, see [[Circle Line (disambiguation)]].}}
{{Use dmy dates|date=August 2020}}
{{Infobox rail line
| name                            = [[File:MRT Singapore Destination 8.svg|25px]] [[File:MRT Singapore Destination 9.svg|25px]] [[File:MRT Singapore Destination 10.svg|25px]]<br />Circle Line
| color                           = {{rcr|SMRT|Circle}}
| native_name                     = {{langx|ms|Laluan MRT Circle}}<br />{{lang-zh|地铁环线}}<br />{{langx|ta|இணைப்பு எம்ஆர்டி வழி}}
| logo                            = Circle Line logo.svg
| logo_width                      = 250px
| image                           = CC6 Stadium MRT Platforms 20201007 161358.jpg
| image_width                     = 300px
| caption                         = [[Alstom Metropolis C830|C830 trainset]] at [[Stadium MRT station|Stadium station]]
| type                            = [[Rapid transit]]<br>[[Light metro]]
| system                          = [[Mass Rapid Transit (Singapore)]]
| status                          = Operational<br />Under construction (Stage 6)
| locale                          = [[Singapore]]
| start                           = [[Dhoby Ghaut MRT station|Dhoby Ghaut]]<br />[[Stadium MRT station|Stadium]]{{efn|Terminus for Marina Bay shuttle during off-peak hours until 2026, then terminus for Dhoby Ghaut shuttle during off-peak hours from 2026}}<br />[[Prince Edward Road MRT station|Prince Edward Road]] (From 2026, during peak hours)
| end                             = [[HarbourFront MRT station|HarbourFront]] (Until 2026)<br />[[Marina Bay MRT station|Marina Bay]] (Until 2026)
| stations                        = 30 (operational)<br />3 (under construction)
| routes                          = 3
| daily_ridership                 = 450,000 (2023)<ref>{{Cite web |title=Rail Reliability |url=https://www.smrt.com.sg/News-Room/Rail-Reliability |url-status=live |archive-url=https://web.archive.org/web/20240507062554/https://www.smrt.com.sg/News-Room/Rail-Reliability |archive-date=7 May 2024 |access-date=5 July 2024 |website=[[SMRT Corporation]]}}</ref>
| open                            = {{start date and age|df=yes|2009|05|28}}<br />(Stage 3)<br />{{start date and age|df=yes|2010|04|17}}<br />(Stages 1 and 2)<br />{{start date and age|df=yes|2011|10|08}} (Stages 4 and 5)<br />{{start date and age|df=yes|2012|01|14}} (Circle Line extension)
| planopen                        = 1H 2026 (Stage 6)
| close                           = 
| owner                           = [[Land Transport Authority]]
| operator                        = [[SMRT Trains|SMRT Trains Ltd]] ([[SMRT Corporation]])
| character                       = Fully underground
| stock                           = [[Alstom Metropolis C830]]<br />[[Alstom Metropolis C830C]]<br />[[Alstom Metropolis C851E]] (future)
| linelength                      = {{convert|35.5|km|mi|abbr=on}} (operational)<br />{{convert|4|km|mi|abbr=on}} (under construction)
| tracklength                     = 
| tracks                          = 
| gauge                           = {{track gauge|sg|allk=on}}
| electrification                 = {{750 V DC|conductor=y}}
| speed                           = limit of {{convert|78|km/h|mph|abbr=on}}
| elevation                       = 
| map                             = {{Circle MRT line|inline=yes}}
| map_state                       = hide
| depot                           = [[Kim Chuan Depot|Kim Chuan]]
}}
{{Maplink|frame=yes|type=line|stroke-colour=#{{rcr|SMRT|Circle}}|text=Interactive Map}}

The '''Circle Line''' ('''CCL''') is a [[Medium-capacity rail system|medium-capacity]] [[Mass Rapid Transit (Singapore)|Mass Rapid Transit]] (MRT) line in [[Singapore]]. It runs in a [[Circle route|loop]] from [[Dhoby Ghaut MRT station|Dhoby Ghaut]] station in the [[Central Area, Singapore|city-centre]] to [[HarbourFront MRT station|HarbourFront]] station in the south via [[Bishan MRT station|Bishan]] station in the [[Central Area, Singapore|centre]] of the country. It also has a branch from [[Promenade MRT station|Promenade]] station to [[Marina Bay MRT station|Marina Bay]] station, which will be extended to [[HarbourFront MRT station|HarbourFront]] station from the first half of 2026 (when Stage 6 commences operation) to form a complete loop. Coloured orange on the rail map, the fully-underground line is approximately {{convert|35.5|km|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 be opened on the network, with the first stage, from [[Bartley MRT station|Bartley]] to [[Marymount MRT station|Marymount]] station, commencing operations on 28 May 2009. The next stage to Dhoby Ghaut was completed on 17 April 2010 and the next stage to HarbourFront opened on 8 October 2011. A two-station extension to Marina Bay station was opened on 14 January 2012. The last stage of the line from [[HarbourFront MRT station| HarbourFront]] to [[Marina Bay MRT station|Marina Bay]] (with stations at [[Keppel MRT station|Keppel]], [[Cantonment MRT station|Cantonment]], and [[Prince Edward Road MRT station|Prince Edward Road]]) will be completed in 2026, completing the loop.

It is the second line in Singapore after the [[North East MRT line|North East Line]] to be [[automatic train operation|completely automated]] and driverless and is among the [[List of driverless trains|world's longest]] driverless [[rapid transit]] lines.<ref name=":1">{{cite web | url=http://www.railway-technology.com/contractors/suburban/alstom/press5.html | title=ALSTOM chosen for the world's longest fully automated metro line in Singapore | publisher=railway-technology.com | date=20 February 2002 | access-date=24 February 2008 | archive-url=https://web.archive.org/web/20071001143403/http://www.railway-technology.com/contractors/suburban/alstom/press5.html | archive-date=1 October 2007 | url-status=live }}</ref> It is also the first [[Medium-capacity rail transport system|medium capacity line]] in Singapore, with each Circle Line train, the [[Alstom Metropolis C830]] and [[Alstom Metropolis C830C|C830C]], having a three-car configuration.

==History==

===Original plans===
[[File:MRT Route Map MR.png|thumb|left|The Marina MRT line as announced in 1997; 18 stations were planned for the line.]]

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.<ref>{{cite web |title=Circle line 'needed with 4 million people' |url=https://eresources.nlb.gov.sg/newspapers/Digitised/Article/straitstimes19891104-1.2.2 |website=The Straits Times (retrieved from NLB) |access-date=6 October 2019 |date=4 November 1989 |archive-url=https://web.archive.org/web/20191006170229/https://eresources.nlb.gov.sg/newspapers/Digitised/Article/straitstimes19891104-1.2.2 |archive-date=6 October 2019 |url-status=live }}</ref>

Feasibility studies for the proposed line commenced on 11 October 1994. 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 to [[Chinatown MRT station|Chinatown]] and Dhoby Ghaut via the [[National Stadium, Singapore|National Stadium]] to either [[Kallang MRT station|Kallang]] or [[Paya Lebar MRT station|Paya Lebar]] stations. The line was planned to have 18 stations, with a possible extension to [[Tanjong Pagar MRT station|Tanjong Pagar]] station.<ref>{{Cite news |date=16 October 1997 |title=Plans for new Marina train line are rolling |work=The Business Times |quote=The proposed {{convert|12|km|miles|adj=on}} Marina line... is likely to start from [[Kallang MRT station]],... (joining) People's Park (Chinatown) station (and) there will be a branch running from Marina Centre to the [[Dhoby Ghaut MRT station]].}}</ref> Plans for the line were confirmed and approved by the government on 12 June 1998.<ref>{{cite web |title=Signing of E&M contracts ceremony |url=http://www.nas.gov.sg/archivesonline/data/pdfdoc/1998061201.htm |website=NAS |access-date=23 November 2019 |date=12 June 1998 |archive-url=https://web.archive.org/web/20200320004337/https://www.nas.gov.sg/archivesonline/data/pdfdoc/1998061201.htm |archive-date=20 March 2020 |url-status=live }}</ref> 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 to [[Stadium MRT station|Stadium]] stations.<ref>{{cite news |title=6 stations |work=The New Paper |date=25 November 1999}}</ref><ref>{{cite news |title=6 stations for Marina line's first phase|work=The Straits Times |date=25 November 1999|page=3}}</ref><ref>{{cite news |title=Marina rail line to be scaled back |work=The Business Times |date=25 November 1999|page=3}}</ref> A part of the removed leg later became part of the [[Downtown MRT line|Downtown Line]].<ref>{{cite book|last1=Colin|first1=Cheong|title=The Circle Line, Linking All Lines|date=2012|isbn=978-981-4342-02-5|page=36|publisher=Land Transport Authority }}</ref> On the other hand, a further extension towards Upper Paya Lebar was announced on 28 April 2001.<ref>{{cite web |title=Circle Line and Kallang/Paya Lebar Expressway |url=https://www.nas.gov.sg/archivesonline/data/pdfdoc/2001042808.htm |website=NAS |access-date=23 November 2019 |date=28 April 2001 |archive-url=https://web.archive.org/web/20200306000711/https://www.nas.gov.sg/archivesonline/data/pdfdoc/2001042808.htm |archive-date=6 March 2020 |url-status=live }}</ref>

The Marina Line was eventually merged with a planned [[Light Rail Transit (Singapore)|Light Rail Transit]] line that went from Paya Lebar to [[Buona Vista MRT station|Buona Vista]] via [[Serangoon MRT station|Serangoon]] and [[Bishan MRT station|Bishan]] to form Circle Line Stage 3 on 20 January 2003,<ref>{{cite web |title=Circle Line Stage 3 |url=http://www.lta.gov.sg/Menu_NewsRelease.htm |archive-url=https://web.archive.org/web/20030526200150/http://www.lta.gov.sg/Menu_NewsRelease.htm |url-status=dead |archive-date=26 May 2003 |website=www.lta.gov.sg |access-date=15 July 2019 |date=20 January 2003}}</ref> and subsequently Circle Line Stage 4 and 5 on 12 December 2003 when Stage 4 was extended from Buona Vista to [[World Trade Centre, Singapore|World Trade Centre]] to close up the link and to provide connectivity from the west to Sentosa, becoming the Circle Line.<ref>{{cite web |title=Completing the Circle via Holland V |url=http://eresources.nlb.gov.sg/newspapers/Digitised/Article/today20031213-1.2.3 |website=Today (retrieved from NLB) |access-date=6 September 2019 |date=13 December 2003 |archive-url=https://web.archive.org/web/20190906173337/http://eresources.nlb.gov.sg/newspapers/Digitised/Article/today20031213-1.2.3 |archive-date=6 September 2019 |url-status=live }}</ref><ref>{{cite web |title=News 5 Tonight (12 December 2003) |url=http://www.nas.gov.sg/archivesonline/audiovisual_records/record-details/57de1bd1-1164-11e3-83d5-0050568939ad |website=MediaCorp (retrieved from NAS) |access-date=19 July 2019 |archive-url=https://web.archive.org/web/20190719031728/http://www.nas.gov.sg/archivesonline/audiovisual_records/record-details/57de1bd1-1164-11e3-83d5-0050568939ad |archive-date=19 July 2019 |url-status=live }}</ref> On 8 August 2001, [[SMRT Corporation|SMRT]] won the bid and was appointed the operator of the Circle Line.<ref>{{cite web |title=Appointment Of Operator For The Circle Line |url=http://app.internet.gov.sg/scripts/lta/3_press_content.asp?start=315 |archive-url=https://web.archive.org/web/20021224094604/http://app.internet.gov.sg/scripts/lta/3_press_content.asp?start=315 |url-status=dead |archive-date=24 December 2002 |website=www.lta.gov.sg |access-date=19 July 2019 |date=8 August 2001}}</ref> Names for the stations for the first three stages of the Circle Line were finalised in July 2005 after the [[Land Transport Authority]] (LTA) conducted a [[public consultation]] exercise on the naming of stations.<ref>{{Cite web|title=Annex A Finalised Names For Circle Line (CCL) Stages 1-3 Stations
|url=http://www.lta.gov.sg/images/Circle%20Line%20Station%20Names%20(Annex%20A).doc|website=www.lta.gov.sg|url-status=dead|archive-url=http://eresources.nlb.gov.sg/webarchives/wayback/20061218084252/http://www.lta.gov.sg/images/Circle%20Line%20Station%20Names%20(Annex%20A).doc|archive-date=18 December 2006}}</ref><ref>{{Cite web|url=http://www.mot.gov.sg/news-centre/news/Detail/Circle%20Line%20Station%20Names%20LTA%20Announces%20Finalised%20Names%20For%20Circle%20Line%20Stages%201-3%20Stations%20And%20Seeks%20Views%20On%20Names%20For%20Circle%20Line%20Stages%204%20And%205%20Stations/|title=Circle Line Station Names LTA Announces Finalised Names For Circle Line Stages 1-3 Stations And Seeks Views On Names For Circle Line Stages 4 And 5 Stations|website=www.mot.gov.sg|language=en|access-date=28 April 2020|archive-url=https://web.archive.org/web/20190129182134/https://www.mot.gov.sg/news-centre/news/Detail/Circle%20Line%20Station%20Names%20LTA%20Announces%20Finalised%20Names%20For%20Circle%20Line%20Stages%201-3%20Stations%20And%20Seeks%20Views%20On%20Names%20For%20Circle%20Line%20Stages%204%20And%205%20Stations/|archive-date=29 January 2019|url-status=live}}</ref> In November 2005, the names of the stations in Stages 4 and 5 were finalised.<ref>{{Cite web|title=Finalised Names For Circle Line (CCL) Stages 4&5 Stations|url=http://www.lta.gov.sg/images/Station%20names%20for%20CCL%20Stages%204%20&%205%20-%20Annex%20A.doc|website=www.lta.gov.sg|url-status=dead|archive-url=http://eresources.nlb.gov.sg/webarchives/wayback/20061218083514/http://www.lta.gov.sg/images/Station%20names%20for%20CCL%20Stages%204%20&%205%20-%20Annex%20A.doc|archive-date=18 December 2006}}</ref><ref>{{Cite web|title=Station Names For Circle Line Stages 4 And 5|url=http://app.lta.gov.sg/apps/news/page.aspx?c=2&id=1419|date=7 November 2005|website=www.lta.gov.sg|url-status=dead|archive-url=https://eresources.nlb.gov.sg/webarchives/2010-04-23%2022:03:36.000/wp/details/http://app.lta.gov.sg/corp_press_content.asp?start=1419|archive-date=23 April 2010}}</ref><ref>{{Cite web|url=http://www.mot.gov.sg/news-centre/news?q=Circle%20line&c=&a=&fm=&fy=&tm=&ty=&p=27|title=MOT Singapore – Gain new perspectives on land, sea & air transport|website=www.mot.gov.sg|language=en|access-date=28 April 2020|archive-date=25 July 2020|archive-url=https://web.archive.org/web/20200725141527/https://www.mot.gov.sg/news-centre/news?q=Circle%20line&c=&a=&fm=&fy=&tm=&ty=&p=27|url-status=live}}</ref>

===Construction of the initial stages===
[[File:Construction of Bishan MRT Circle Line 2005-03-29.JPG|thumb|left|The construction of Bishan station]]

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, the [[Nicoll 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.<ref name="auto">{{cite book|last1=Colin|first1=Cheong|title=The Circle Line, Linking All Lines|date=2012|isbn=978-981-4342-02-5|page=46|publisher=Land Transport Authority }}</ref><ref>{{cite web|url=http://motoring.asiaone.com/Motoring/Motorworld/Story/A1Story20090818-161682.html|title=Circle Line could cost taxpayers $10 billion|publisher=AsiaOne Motoring|access-date=21 August 2016|url-status=dead|archive-url=https://web.archive.org/web/20111008134221/http://motoring.asiaone.com/Motoring/Motorworld/Story/A1Story20090818-161682.html|archive-date=8 October 2011}}</ref> Due to the collapse, the station was relocated to a new site two-thirds the size of the original {{convert|100|m|ft}} away.<ref>[http://www.straitstimes.com/Free/Story/STIStory_157967.html "Circle line will exceed $6.7b budget"] {{Webarchive|url=https://web.archive.org/web/20071113174139/http://www.straitstimes.com/Free/Story/STIStory_157967.html |date=13 November 2007 }} Christopher Tan, [[The Straits Times]], 15 September 2007</ref> 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), leaving [[Bukit Brown MRT station|Bukit Brown]] as the only unopened station on the line.<ref name="auto"/>

The first section of the line, Stage 3, a {{convert|5|km|mi}} five-station segment stretching from Bartley to Marymount, opened on 28 May 2009.<ref name="News">{{cite web | access-date=28 May 2009 | archive-date=28 May 2009 | archive-url=https://web.archive.org/web/20090528095244/http://www.channelnewsasia.com/stories/singaporelocalnews/view/432074/1/.html | url=http://www.channelnewsasia.com/stories/singaporelocalnews/view/432074/1/.html | title=Part of Circle Line opens today | publisher=ChannelNewsAsia | date=28 May 2009}}</ref><ref>{{cite web|url=http://www.lta.gov.sg/content/dam/ltaweb/corp/PublicTransport/files/Early-Opening-for-CCL-from-Bartley-to-Marymount.pdf|title=Early Opening for Circle Line from Bartley to Marymount|access-date=16 April 2009|website=www.lta.gov.sg|archive-url=http://eresources.nlb.gov.sg/webarchives/wayback/20130221220424/http://www.lta.gov.sg/content/dam/ltaweb/corp/PublicTransport/files/Early-Opening-for-CCL-from-Bartley-to-Marymount.pdf|archive-date=21 February 2013|url-status=dead}}</ref> Initial ridership on this section was lower than estimated, at 32,000 passengers per day (ppd) instead of the estimated 55,000 ppd.<ref>{{cite web|url=http://www.channelnewsasia.com/stories/singaporelocalnews/view/449350/1/.html|title=LTA completes final tunnelling work on Circle Line|publisher=Channel News Asia|date=17 August 2009|archive-url=https://web.archive.org/web/20121019161745/http://www.channelnewsasia.com/stories/singaporelocalnews/view/449350/1/.html|archive-date=19 October 2012}}</ref> Tunneling works for the entire line were completed on 17 August 2009.<ref>{{cite web|url=http://www.straitstimes.com/Breaking%2BNews/Singapore/Story/STIStory_417858.html?vgnmr=1|title=Circle Line: The longest dig|publisher=The Straits Times|date=17 August 2009|archive-url=https://web.archive.org/web/20090821173820/https://www.straitstimes.com/Breaking%2BNews/Singapore/Story/STIStory_417858.html?vgnmr=1|archive-date=21 August 2009}}</ref> Stages 1 and 2 started operations on 17 April 2010,<ref>{{Cite web|title=Welcome Remarks By Mr Raymond Lim At The Opening Of The Circle Line From Dhoby Ghaut To Bartley on 16 April 2010|url=http://www.mot.gov.sg/news-centre/news/Detail/Welcome%20Remarks%20By%20Mr%20Raymond%20Lim%20At%20The%20Opening%20Of%20The%20Circle%20Line%20(From%20Dhoby%20Ghaut%20To%20Bartley)%20on%2016%20April%202010/|website=www.mot.gov.sg|language=en|access-date=1 May 2020|archive-date=1 May 2020|archive-url=https://web.archive.org/web/20200501111454/https://www.mot.gov.sg/news-centre/news/Detail/Welcome%20Remarks%20By%20Mr%20Raymond%20Lim%20At%20The%20Opening%20Of%20The%20Circle%20Line%20(From%20Dhoby%20Ghaut%20To%20Bartley)%20on%2016%20April%202010/|url-status=dead}}</ref><ref>{{cite web |url=http://app.lta.gov.sg/corp_press_content.asp?start=kpt8zx9w8ik53wi33gr59p754348fsj35b9glldouy8ndlh7kb |title=Circle Line from Bartley to Dhoby Ghaut to Open 17 April |access-date=26 January 2010 |url-status=dead |archive-url=https://web.archive.org/web/20110621220756/http://app.lta.gov.sg/corp_press_content.asp?start=kpt8zx9w8ik53wi33gr59p754348fsj35b9glldouy8ndlh7kb |archive-date=21 June 2011|website=www.lta.gov.sg }}</ref> followed by Stages 4 and 5 (from the [[Marymount MRT station|Marymount]] to HarbourFront stations) on 8 October 2011.<ref>{{Cite web|title=Connect - October 2011|url=https://www.lta.gov.sg/content/dam/ltaweb/corp/PublicationsResearch/files/ReportNewsletter/Connect/connect_oct_2011.pdf|website=www.lta.gov.sg|url-status=dead|archive-url=http://eresources.nlb.gov.sg/webarchives/wayback/20180205094159/https://www.lta.gov.sg/content/dam/ltaweb/corp/PublicationsResearch/files/ReportNewsletter/Connect/connect_oct_2011.pdf|archive-date=5 February 2018}}</ref><ref>{{Cite web|title=Speech by Mr Tharman Shanmugaratnam at the Circle Line Opening Ceremony on 7 Oct 2011|url=http://www.mot.gov.sg/news-centre/news/Detail/Speech%20by%20Mr%20Tharman%20Shanmugaratnam%20at%20the%20Circle%20Line%20Opening%20Ceremony%20on%207%20Oct%202011/|website=www.mot.gov.sg|language=en|access-date=1 May 2020|archive-date=1 May 2020|archive-url=https://web.archive.org/web/20200501111937/https://www.mot.gov.sg/news-centre/news/Detail/Speech%20by%20Mr%20Tharman%20Shanmugaratnam%20at%20the%20Circle%20Line%20Opening%20Ceremony%20on%207%20Oct%202011/|url-status=live}}</ref><ref>{{Cite web|url=http://www.mot.gov.sg/news-centre/highlights/detail/circle-line-from-marymount-to-harbourfront-to-open|title=Circle Line from Marymount to HarbourFront to open|website=www.mot.gov.sg|language=en|access-date=28 April 2020|archive-date=19 November 2020|archive-url=https://web.archive.org/web/20201119125715/https://www.mot.gov.sg/news-centre/highlights/detail/circle-line-from-marymount-to-harbourfront-to-open|url-status=live}}</ref><ref>{{cite web|url=http://sg.news.yahoo.com/blogs/singaporescene/final-batch-circle-line-stations-open-004355257.html|title=Train crowding to ease with launch of full Circle line: Minister Lui|date=2 August 2011 |access-date=21 August 2016|archive-url=https://web.archive.org/web/20160413133839/https://sg.news.yahoo.com/blogs/singaporescene/final-batch-circle-line-stations-open-004355257.html|archive-date=13 April 2016|url-status=live}}</ref> A two-station extension to Marina Bay opened on 14 January 2012.<ref>{{Cite web|url=http://www.smrt.com.sg/Announcements/articleid/630|title=The extension on Circle Line opens with two events held concurrently at Bayfront Station and Esplanade Xchange|website=www.smrt.com.sg|access-date=22 April 2020|archive-url=https://web.archive.org/web/20200422010155/http://www.smrt.com.sg/Announcements/articleid/630|archive-date=22 April 2020|url-status=live}}</ref><ref>{{Cite web|url=http://www.mot.gov.sg/news-centre/news/Detail/Speech%20by%20Mr%20Lui%20Tuck%20Yew%20at%20the%20Opening%20Ceremony%20of%20the%20Circle%20Line%20Extension%20on%2013%20January%202012/|title=Speech by Mr Lui Tuck Yew at the Opening Ceremony of the Circle Line Extension on 13 January 2012|website=www.mot.gov.sg|language=en|access-date=21 April 2020|archive-date=4 September 2020|archive-url=https://web.archive.org/web/20200904091109/https://www.mot.gov.sg/news-centre/news/Detail/Speech%20by%20Mr%20Lui%20Tuck%20Yew%20at%20the%20Opening%20Ceremony%20of%20the%20Circle%20Line%20Extension%20on%2013%20January%202012/|url-status=live}}</ref><ref>{{Cite web|url=http://www.mot.gov.sg/news-centre/highlights/detail/circle-line-and-tuas-west-extension-updates|title=Circle Line and Tuas West Extension updates|website=www.mot.gov.sg|language=en|access-date=21 April 2020|archive-date=3 September 2020|archive-url=https://web.archive.org/web/20200903130555/https://www.mot.gov.sg/news-centre/highlights/detail/circle-line-and-tuas-west-extension-updates|url-status=live}}</ref><ref>{{Cite web|url=http://www.mot.gov.sg/news-centre/news/Detail/Speech%20by%20Mr%20Lui%20Tuck%20Yew%20at%20the%20Downtown%20Line%203%20Groundbreaking%20Ceremony/|title=Speech by Mr Lui Tuck Yew at the Downtown Line 3 Groundbreaking Ceremony|website=www.mot.gov.sg|language=en|access-date=28 April 2020}}{{Dead link|date=May 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>
{{clear left}}

===Circle Line stage 6===
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.<ref>{{Cite web |title=Factsheet: Completion of Circle Line 6 Tunnelling Works |url=https://www.lta.gov.sg/content/ltagov/en/newsroom/2022/1/news-releases/Completion_CCL6_tunnelling_works.html |url-status=live |archive-url=https://web.archive.org/web/20220112050732/https://www.lta.gov.sg/content/ltagov/en/newsroom/2022/1/news-releases/Completion_CCL6_tunnelling_works.html |archive-date=12 January 2022 |access-date= }}</ref> The 4&nbsp;km extension will run between [[Marina Bay MRT station|Marina Bay]] and [[HarbourFront MRT station|HarbourFront]].<ref>{{cite web |url=https://www.mot.gov.sg/news-centre/news/Detail/Speech%20by%20Mr%20Lui%20Tuck%20Yew%20at%20visit%20to%20DTL1%20Chinatown%20Station%20on%2017%20January%202013/ |title=Speech by Mr Lui Tuck Yew at visit to DTL1 Chinatown Station on 17 January 2013 |website=MOT |access-date=19 September 2019 |date=17 January 2013 |archive-url=https://web.archive.org/web/20200226205104/https://www.mot.gov.sg/news-centre/news/Detail/Speech%20by%20Mr%20Lui%20Tuck%20Yew%20at%20visit%20to%20DTL1%20Chinatown%20Station%20on%2017%20January%202013/ |archive-date=26 February 2020 |url-status=live }}</ref><ref>{{cite web|url=http://www.lta.gov.sg/content/ltaweb/en/public-transport/projects/circle-line-6.html|title=Circle line 6 - Projects - Public Transport - Land Transport Authority|access-date=21 August 2016|archive-url=https://web.archive.org/web/20160105072640/http://www.lta.gov.sg/content/ltaweb/en/public-transport/projects/circle-line-6.html|archive-date=5 January 2016|url-status=live}}</ref> 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 being [[Keppel MRT station|Keppel]], [[Cantonment MRT station|Cantonment]], and [[Prince Edward Road MRT station|Prince Edward]]. Tenders were called for construction between 2016 and 2017.<ref>{{Cite web|url=https://www.lta.gov.sg/apps/tender/default.aspx?scr=yes&Ref=882&scrdate=&fromdate=&todate=&keyword=keppel|title=Tender information {{!}} Land Transport Authority|website=www.lta.gov.sg|language=en|access-date=23 April 2017|archive-url=https://web.archive.org/web/20170424002657/https://www.lta.gov.sg/apps/tender/default.aspx?scr=yes&Ref=882&scrdate=&fromdate=&todate=&keyword=keppel|archive-date=24 April 2017|url-status=live}}</ref><ref>{{Cite web|url=https://www.lta.gov.sg/apps/tender/default.aspx?scr=yes&Ref=&scrdate=&fromdate=&todate=&keyword=cantonment|title=Tender information {{!}} Land Transport Authority|website=www.lta.gov.sg|language=en|access-date=23 April 2017|archive-url=https://web.archive.org/web/20170424085416/https://www.lta.gov.sg/apps/tender/default.aspx?scr=yes&Ref=&scrdate=&fromdate=&todate=&keyword=cantonment|archive-date=24 April 2017|url-status=live}}</ref><ref>{{Cite web|url=https://www.lta.gov.sg/apps/tender/default.aspx?scr=yes&Ref=&scrdate=&fromdate=&todate=&keyword=prince|title=Tender information {{!}} Land Transport Authority|website=www.lta.gov.sg|language=en|access-date=23 April 2017|archive-url=https://web.archive.org/web/20170424002406/https://www.lta.gov.sg/apps/tender/default.aspx?scr=yes&Ref=&scrdate=&fromdate=&todate=&keyword=prince|archive-date=24 April 2017|url-status=live}}</ref>

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.<ref>{{Cite web|url=https://www.lta.gov.sg/apps/news/page.aspx?c=2&id=5cf30fa9-12bd-463d-a481-120c410dcb99|title=LTA Invites Public to Suggest MRT station Names for Circle line 6 stations {{!}} Press Room {{!}} Land Transport Authority|website=www.lta.gov.sg|language=en|access-date=18 September 2017|archive-url=https://web.archive.org/web/20170918201927/https://www.lta.gov.sg/apps/news/page.aspx?c=2&id=5cf30fa9-12bd-463d-a481-120c410dcb99|archive-date=18 September 2017|url-status=live}}</ref><ref>{{cite web| url=http://www.channelnewsasia.com/news/singapore/wanted-names-for-3-new-circle-line-stations-8847558| website=Channel NewsAsia| access-date=15 May 2017| title=Wanted: Names for 3 new Circle line stations| date=15 May 2017| archive-url=https://web.archive.org/web/20170516182519/http://www.channelnewsasia.com/news/singapore/wanted-names-for-3-new-circle-line-stations-8847558| archive-date=16 May 2017| url-status=live}}</ref> The Keppel and Cantonment stations kept their names, while Prince Edward station was changed to Prince Edward Road station.<ref>{{Cite news|url=https://www.straitstimes.com/singapore/transport/excavation-for-circle-line-6-to-start-in-middle-of-next-year|title=Excavation for Circle Line 6 to start in middle of next year|date=28 September 2018|work=The Straits Times|access-date=13 October 2018|language=en|archive-url=https://web.archive.org/web/20181013211735/https://www.straitstimes.com/singapore/transport/excavation-for-circle-line-6-to-start-in-middle-of-next-year|archive-date=13 October 2018|url-status=live}}</ref>

Construction of Stage 6 commenced in late 2017. A [[joint venture]] – by [[China State Construction Engineering]] (The Singapore branch) and Nishimatsu Construction – won the contract to build the new Keppel station and its associated tunnels.<ref>{{Cite web|url=http://www.channelnewsasia.com/news/singapore/first-circle-line-6-contracts-worth-s-1-75b-awarded-by-lta-9198368|title=First CCL6 contracts awarded by LTA|publisher=ChannelNewsAsia|access-date=12 October 2017|archive-url=https://web.archive.org/web/20171012150146/http://www.channelnewsasia.com/news/singapore/first-circle-line-6-contracts-worth-s-1-75b-awarded-by-lta-9198368|archive-date=12 October 2017|url-status=live}}</ref><ref>{{Cite web|url=http://www.straitstimes.com/singapore/construction-of-circle-line-6-to-start-by-end-of-2017-first-three-civil-contracts-awarded|title=Construction of Circle line 6 to start by end of 2017, first three civil contracts awarded|date=8 September 2017|publisher=[[The Straits Times]]|access-date=12 October 2017|archive-url=https://web.archive.org/web/20171012100436/http://www.straitstimes.com/singapore/construction-of-circle-line-6-to-start-by-end-of-2017-first-three-civil-contracts-awarded|archive-date=12 October 2017|url-status=live}}</ref>

Stage 6 of the line is now expected to be completed by 2026 instead due to delays caused by the [[COVID-19 pandemic in Singapore|COVID-19 pandemic]].<ref>{{Cite web|title=Speech by Minister For Transport Mr Ong Ye Kung at MOT Committee of Supply Debate 2021 on A Tale of Three Connections|url=http://www.mot.gov.sg/news-centre/news/Detail/speech-by-minister-for-transport-mr-ong-ye-kung-at-mot-committee-of-supply-debate-2021-on-a-tale-of-three-connections/|access-date=2021-03-08|website=www.mot.gov.sg|language=en|archive-date=14 April 2021|archive-url=https://web.archive.org/web/20210414222045/https://www.mot.gov.sg/news-centre/news/Detail/speech-by-minister-for-transport-mr-ong-ye-kung-at-mot-committee-of-supply-debate-2021-on-a-tale-of-three-connections/|url-status=live}}</ref> Tunnelling works for the CCL6 were completed on 12 January 2022, with a final tunnel breakthrough from Prince Edward Road station into Cantonment station.<ref name="Auto 2022">{{cite web | last=Tan | first=Christopher | title=Tunnelling works for Circle Line MRT extension completed | website=The Straits Times | date=12 January 2022 | url=https://www.straitstimes.com/singapore/transport/tunnelling-works-for-circle-line-mrt-extension-completed | access-date=12 January 2022 | archive-date=12 January 2022 | archive-url=https://web.archive.org/web/20220112025858/https://www.straitstimes.com/singapore/transport/tunnelling-works-for-circle-line-mrt-extension-completed | url-status=live }}</ref> The tunnels between Cantonment station and the adjacent Prince Edward Road station were constructed only {{convert|6.7|m|ft}} below the former [[Tanjong Pagar railway station|Tanjong 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.<ref name="CNA 2022">{{cite web | title=Circle Line 6 tunnelling works complete, 3 new stations set to open in 2026 | website=CNA | date=12 January 2022 | url=https://www.channelnewsasia.com/singapore/circle-line-6-extension-tunnelling-complete-keppel-cantonment-prince-edward-road-2429691 | access-date=12 January 2022 | archive-date=12 January 2022 | archive-url=https://web.archive.org/web/20220112053403/https://www.channelnewsasia.com/singapore/circle-line-6-extension-tunnelling-complete-keppel-cantonment-prince-edward-road-2429691 | url-status=live }}</ref> 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.<ref name="LTA 2022">{{cite web | title=Factsheet: Completion of Circle Line 6 Tunnelling Works | website=LTA | date=12 January 2022 | url=https://www.lta.gov.sg/content/ltagov/en/newsroom/2022/1/news-releases/Completion_CCL6_tunnelling_works.html | access-date=12 January 2022 | archive-date=12 January 2022 | archive-url=https://web.archive.org/web/20220112050732/https://www.lta.gov.sg/content/ltagov/en/newsroom/2022/1/news-releases/Completion_CCL6_tunnelling_works.html | url-status=live }}</ref>

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).<ref>{{Cite news |last=Kok |first=Yufeng |date=6 December 2024 |title=Hume MRT station to open in Q2 2025; Circle Line Stage 6 to be ready in first half of 2026 |url=https://www.straitstimes.com/singapore/transport/hume-mrt-station-to-open-in-q2-2025-circle-line-stage-6-to-be-completed-in-first-half-of-2026-chee |access-date=6 December 2024 |work=[[The Straits Times]] |archive-date=6 December 2024 |archive-url=https://web.archive.org/web/20241206111213/https://www.straitstimes.com/singapore/transport/hume-mrt-station-to-open-in-q2-2025-circle-line-stage-6-to-be-completed-in-first-half-of-2026-chee |url-status=live }}</ref>

==Incidents==

===Nicoll Highway collapse===
{{Main|Nicoll Highway collapse}}
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, Singapore|Merdeka Bridge]]. The accident left a collapse zone that was {{convert|150|m|ft}} wide, {{convert|100|m|ft}} long, and {{convert|30|m|ft}} deep. Four workers were killed, and three were injured.<ref name=":0">{{Cite web|url=http://www.nas.gov.sg/archivesonline/data/pdfdoc/20050513987.pdf|title=COMMITTEE OF INQUIRY CONCLUDES STRING OF CRITICAL DESIGN ERRORS CAUSED COLLAPSE AT NICOLL HIGHWAY.|date=13 May 2005|access-date=18 September 2017|archive-url=https://web.archive.org/web/20160509210436/http://www.nas.gov.sg/archivesonline/data/pdfdoc/20050513987.pdf|archive-date=9 May 2016|url-status=live}}</ref>

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 [[subcontractor]]s were reprimanded and issued warnings in connection with the accident.<ref name=":0" />

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 {{convert|100|m|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 current [[Downtown MRT line|Downtown line]].<ref>{{Cite book|last1=Colin|first1=Cheong|title=The Circle Line, Linking All Lines|date=2012|isbn=978-981-4342-02-5|page=42|publisher=Land Transport Authority }}</ref>

===Other incidents===
On 16 August 2007, the [[Building and Construction Authority]] (BCA) issued a stop-work order and revoked the contractor's tunnelling permit after a {{convert|7|m|ft|adj=on}} stretch of two lanes close to the junction of Telok Blangah Road and Alexandra Road sank about {{convert|20|cm|in}} that evening.<ref>[http://www.straitstimes.com/Free/Story/STIStory_150531.html "Stop-work order at Telok Blangah site is fourth this year on $6.7b MRT project"] {{Webarchive|url=https://web.archive.org/web/20080609193530/http://www.straitstimes.com/Free/Story/STIStory_150531.html |date=9 June 2008 }} T. Rajan, [[The Straits Times]], 22 August 2007</ref>

A section of the road above a construction site near [[Holland Road, Singapore|Holland 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.<ref>[http://www.channelnewsasia.com/stories/singaporelocalnews/view/349771/1/.html "Road above Circle line construction site caves in"] {{Webarchive|url=https://web.archive.org/web/20080526221930/http://www.channelnewsasia.com/stories/singaporelocalnews/view/349771/1/.html |date=26 May 2008 }} CNA Live, [[Channel NewsAsia]], 24 May 2008</ref>

===Line disruptions===
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 that [[leak]]s and a damaged [[electrical cable]] along the Circle Line were the cause of the disruption.<ref>{{cite news|title=Leaks, damaged cable cause of 4-hour delay on Circle line|url=http://www.straitstimes.com/BreakingNews/Singapore/Story/STIStory_717665.html |access-date=19 October 2011|newspaper=The Straits Times|date=29 September 2011|archive-url= https://web.archive.org/web/20111017092020/http://www.straitstimes.com/BreakingNews/Singapore/Story/STIStory_717665.html |archive-date=17 October 2011|url-status=live}}</ref> The disruption started at about 5.30am. Train services were gradually restored from 8am and all services were restored just before 10am. [[Dakota MRT station|Dakota]] and [[Mountbatten MRT station|Mountbatten]] stations were the last two to resume operations.<ref>{{cite news|title=Thousands affected by Circle line disruption|url=http://www.channelnewsasia.com/stories/singaporelocalnews/view/1154288/1/.html |access-date=19 October 2011|newspaper=Channel News Asia|date=20 September 2011|archive-url= https://web.archive.org/web/20111024121131/http://www.channelnewsasia.com/stories/singaporelocalnews/view/1154288/1/.html |archive-date=24 October 2011|url-status=live}}</ref> Investigations were carried out, and the fault was traced back to a faulty cable beneath the platform level at Dakota station.<ref>{{cite news|title=Faulty cable led to Circle line disruption|url=http://www.channelnewsasia.com/stories/singaporelocalnews/view/1154317/1/.html |access-date=19 October 2011|newspaper=Channel News Asia|date=20 September 2011|archive-url= https://web.archive.org/web/20111026103638/http://www.channelnewsasia.com/stories/singaporelocalnews/view/1154317/1/.html |archive-date=26 October 2011|url-status=live}}</ref> 27,000 passengers were affected by the disruption during the four hour delay, with bus bridging services plying the Circle Line route.<ref>{{cite news|title=Call for thorough probe on Circle line disruption|url=http://www.channelnewsasia.com/stories/singaporelocalnews/view/1154777/1/.html |access-date=19 October 2011|newspaper=Channel News Asia|date=22 September 2011|archive-url= https://web.archive.org/web/20111025052943/http://www.channelnewsasia.com/stories/singaporelocalnews/view/1154777/1/.html |archive-date=25 October 2011|url-status=live}}</ref>

In late August 2016, intermittent signal interference led to a five-day series of train disruptions. The issue reappeared in November.<ref>{{Cite news|url=http://www.todayonline.com/singapore/no-service-6-circle-line-stations-disruption-caused-signal-fault-widens |title=Signal interference issue plagues Circle line again|newspaper=TODAYonline|access-date=3 December 2016|archive-url= https://web.archive.org/web/20161220213437/http://www.todayonline.com/singapore/no-service-6-circle-line-stations-disruption-caused-signal-fault-widens |archive-date=20 December 2016|url-status=live}}</ref><ref>{{Cite news|url=http://www.straitstimes.com/singapore/transport/circle-line-signal-fault-that-caused-train-disruptions-on-wednesday-morning |title=Circle line signal fault that caused train disruptions on Wednesday similar to problem in September: LTA, SMRT|date=2 November 2016|newspaper=The Straits Times|access-date=3 December 2016|archive-date=30 November 2016|archive-url= https://web.archive.org/web/20161130085450/http://www.straitstimes.com/singapore/transport/circle-line-signal-fault-that-caused-train-disruptions-on-wednesday-morning |url-status=live}}</ref> A team of [[Data science|data scientists]] explored the data and discovered via a [[Étienne-Jules Marey|Marey]] [[time–distance diagram|chart visualization]] that it was caused by hardware problems, sending errant signals from a "rogue" train, PV46.<ref>{{Cite web |url=https://medium.com/datagovsg-blog/how-we-caught-the-circle-line-rogue-train-with-data-79405c86ab6a |title=How the Circle line rogue train was caught with data |website=Medium |first=Daniel |last=Sim |date=1 December 2016 |publisher=Data.gov.sg Blog |access-date=2024-12-06 |archive-date=7 December 2024 |archive-url=https://web.archive.org/web/20241207000059/https://medium.com/datagovsg-blog/how-we-caught-the-circle-line-rogue-train-with-data-79405c86ab6a |url-status=live }}</ref>

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.<ref>{{Cite web |title=Circle Line train services resume after 14-hour disruption |url=https://www.channelnewsasia.com/singapore/circle-line-delay-mrt-train-services-crack-rail-track-fault-3807371 |archive-url=https://web.archive.org/web/20230930043050/https://www.channelnewsasia.com/singapore/circle-line-delay-mrt-train-services-crack-rail-track-fault-3807371 |archive-date=2023-09-30 |access-date= |website=CNA |language=en}}</ref>

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.<ref>{{Cite news |last=Chin |first=Hui Shan |date=2024-09-17 |title=MRT service resumes on Circle Line after power fault causes delay for commuters |url=https://www.straitstimes.com/singapore/power-fault-on-circle-line-causes-delay-for-mrt-commuters |access-date=2024-09-26 |work=The Straits Times |language=en |issn=0585-3923 |archive-date=26 September 2024 |archive-url=https://web.archive.org/web/20240926123544/https://www.straitstimes.com/singapore/power-fault-on-circle-line-causes-delay-for-mrt-commuters |url-status=live }}</ref><ref>{{Cite web |title=Train services fully resume on Circle Line after disruption caused by power fault |url=https://www.channelnewsasia.com/singapore/circle-line-power-fault-disruption-sep-17-4613076 |access-date=2024-09-26 |website=CNA |language=en}}</ref> 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.<ref name=":2">{{Cite web |title=Circle Line shutdown on Sep 17: Maintenance team did not follow protocol, says SMRT |url=https://www.channelnewsasia.com/singapore/circle-line-shutdown-smrt-protocol-lapse-mrt-train-disruptions-4639096 |access-date=2024-09-26 |website=CNA |language=en |archive-date=26 September 2024 |archive-url=https://web.archive.org/web/20240926123544/https://www.channelnewsasia.com/singapore/circle-line-shutdown-smrt-protocol-lapse-mrt-train-disruptions-4639096 |url-status=live }}</ref>

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.<ref name=":2" />

==Network and operations==

=== Network ===
The Circle Line is the second line in Singapore to be [[automatic train operation|completely automated]] and driverless, following the [[North East MRT line|North East line]], and is among the world's longest driverless [[rapid transit]] lines.<ref name=":1" /> It is also the first [[Medium-capacity rail transport system|medium capacity line]] in Singapore.{{Citation needed|date=August 2023}}

===Route===
[[File:MRT Route Map CC.svg|500px|thumb|Geographically accurate map of the Circle Line<ref>{{Cite web |title=Circle Line 6 tunnelling works complete, 3 new stations set to open in 2026 |url=https://www.channelnewsasia.com/singapore/circle-line-6-extension-tunnelling-complete-keppel-cantonment-prince-edward-road-2429691 |access-date=2023-08-29 |website=CNA |language=en |archive-date=12 January 2022 |archive-url=https://web.archive.org/web/20220112053403/https://www.channelnewsasia.com/singapore/circle-line-6-extension-tunnelling-complete-keppel-cantonment-prince-edward-road-2429691 |url-status=live }}</ref>|alt=Refer to caption.]]

The {{convert|35.5|km|miles|adj=on}} Circle Line forms an incomplete loop from [[Dhoby Ghaut]] in the [[Central Region, Singapore|Central Region of Singapore]], north to [[Serangoon]] and [[Bishan, Singapore|Bishan]], and south to [[HarbourFront]], with a branch from [[Promenade MRT station|Promenade]] to [[Marina Bay MRT station|Marina Bay]] station which will be extended to HarbourFront in 2026. The fully-underground circular route also makes several links with the other MRT lines.<ref>{{Cite web|url=https://www.lta.gov.sg/content/ltagov/en/getting_around/public_transport/rail_network/circle_line.html|title=LTA {{!}} Getting Around {{!}} Public Transport {{!}} Rail Network {{!}} Circle Line|website=www.lta.gov.sg|access-date=29 April 2020|archive-date=1 November 2019|archive-url=https://web.archive.org/web/20191101093906/https://www.lta.gov.sg/content/ltagov/en/getting_around/public_transport/rail_network/circle_line.html|url-status=live}}</ref> The line begins at Dhoby Ghaut station, which has an interchange with the [[North–South MRT line|North–South]] and [[North East MRT line|North East]] lines, going eastwards and paralleling [[Bras Basah Road]] and Raffles Boulevard, before joining the Circle Line extension at Promenade station, which also interchanges with the [[Downtown MRT line|Downtown line]]. From Promenade station, the line goes northwards and towards the east, passing beneath the [[Kallang Basin]]. Between the [[Stadium MRT station|Stadium]] and [[Dakota MRT station|Dakota]] stations, the line parallels Stadium Boulevard and [[Old Airport Road, Singapore|Old Airport Road]], then the line continues northwards and follows the route of Paya Lebar Road and Upper Paya Lebar Road between the [[Paya Lebar MRT station|Paya Lebar]] (which interchanges with the [[East–West MRT line|East–West Line]]) and [[Tai Seng MRT station|Tai Seng]] stations.

The line curves and continues westwards between the [[Bartley MRT station|Bartley]] and [[Marymount MRT station|Marymount]] stations, also interchanging with the North East and North–South lines at [[Serangoon MRT station|Serangoon]] and [[Bishan MRT station|Bishan]] stations respectively, and then it continues in a general southwest direction between [[Caldecott MRT station|Caldecott]] and [[Kent Ridge MRT station|Kent Ridge]], the former having an interchange with the [[Thomson–East Coast MRT line|Thomson East-Coast line]], passing through [[Bukit Brown Cemetery]] between the Caldecott and [[Botanic Gardens MRT station|Botanic Gardens]] stations. The line also interchanges with the Downtown line at [[Botanic Gardens MRT station|Botanic Gardens]] station and the East–West Line at [[Buona Vista MRT station|Buona Vista]] station. After Kent Ridge station, the line curves eastwards, paralleling the [[West Coast Highway, Singapore|West Coast Highway]] and then terminating at HarbourFront station, where it interchanges with the [[North East MRT line|North East Line]].

From 2026, upon the completion of Stage 6, the Circle Line will continue eastwards from HarbourFront, paralleling Keppel Road and [[Ayer 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 underneath [[Marina Bay Sands]] at [[Bayfront MRT station|Bayfront station]], which it serves and has [[cross-platform interchange]] with the Downtown Line. Also, end-destination number 8 and 9 will be replaced by clockwise and counter-clockwise loops.

===Stations===
Station codes for the line are orange, corresponding to the line's colour on the system map.<ref>{{Cite web |title=Is the Circle Line yellow or orange? LTA & SMRT have an answer. |url=https://mothership.sg/2020/12/circle-line-yellow-or-orange/ |url-status=live |archive-url=https://web.archive.org/web/20201224114320/https://mothership.sg/2020/12/circle-line-yellow-or-orange/ |archive-date=24 December 2020 |access-date=2020-12-28 |website=mothership.sg |language=en}}</ref> All stations have island platforms, with the exception of [[Promenade MRT station|Promenade]] and future infill station [[Bukit Brown MRT station|Bukit Brown]].

{| class="wikitable"
|+ Circle Line stations timeline
! Date !! Project !! Description
|-
| 28 May 2009 || Stage 3 || [[Bartley MRT station|Bartley]] – [[Marymount MRT station|Marymount]] 
|-
| 17 April 2010 || Stage 1 & 2 || [[Bartley MRT station|Bartley]] – [[Dhoby Ghaut MRT station|Dhoby Ghaut]] 
|-
| 8 October 2011 || Stage 4 & 5 || [[Marymount MRT station|Marymount]] – [[HarbourFront MRT station|HarbourFront]] 
|-
| 14 January 2012 || Circle Line Extension || [[Promenade MRT station|Promenade]] – [[Marina Bay MRT station|Marina Bay]] 
|-
| 1H 2026 || Stage 6 || [[HarbourFront MRT station|HarbourFront]] – [[Marina Bay MRT station|Marina Bay]] 
|-
| Future || Future stations between existing stations || [[Bukit Brown MRT station|Bukit Brown station]] between [[Caldecott MRT station|Caldecott]] and [[Botanic Gardens MRT station|Botanic Gardens]]
|}

'''Legend'''
{| class="wikitable" style="text-align:center;"
|-
| [[File:Aiga escalator up.svg|15px|link=]]<br />Elevated || [[File:MRT Singapore Destination 1.svg|15px|link=]]&nbsp;[[File:MRT Singapore Destination 14.svg|15px|link=]]<br />Line [[Train station#Terminus|terminus]] || [[File:Barrier turnstile icon.svg|12px|link=]]<br />Transfer outside [[paid area]]
|-
| [[File:Aiga escalator.svg|15px|link=]]<br />Ground-level
| style='border-style: none none none none;' | [[File:MUTCD D9-6.svg|15px|link=]]<br />Wheelchair accessible
| [[File:Bus-logo.svg|15px|link=]]<br />Bus interchange
|-
| [[File:Aiga escalator down.svg|15px|link=]]<br />Underground || [[File:ISO 7010 W003.svg|15px|link=]]<br />[[Singapore Civil Defence Force|Civil Defence]] [[Air raid shelter|Shelter]]
| [[File:Aiga carrental cropped.svg|10px|link=]]&nbsp;[[File:BSicon Mono-CHN.svg|10px|link=]]&nbsp;[[File:BSicon AETRAM.svg|10px|link=]]&nbsp;[[File:Aiga watertransportation.svg|10px|link=]]&nbsp;[[File:20 airtransportation.svg|10px|link=]]&nbsp;[[File:Aiga immigration.svg|10px|link=]]<br />Other transportation modes
|}
'''List'''
{| class="wikitable" style="border-collapse: collapse; font-size: 95%"
|-
! scope="col" style="background:#{{rcr|SMRT|Circle}}" | Station code
! scope="col" style="background:#{{rcr|SMRT|Circle}}" | Station name
! scope="col" style="background:#{{rcr|SMRT|Circle}}" | Images
! scope="col" style="background:#{{rcr|SMRT|Circle}}" | Interchange;<br /><small>Adjacent transportation</small>
! scope="col" style="background:#{{rcr|SMRT|Circle}}" | Opening
! scope="col" style="background:#{{rcr|SMRT|Circle}}" | Cost
|-
|scope="row"|[[File:MRT Singapore Destination 8.svg|15px]]<br />{{SMRT code|CC|1|NS|24|NE|6}}<br />[[File:Aiga escalator down.svg|15px|link=]]&nbsp;[[File:MUTCD D9-6.svg|15px|link=]]||[[Dhoby Ghaut MRT station|Dhoby Ghaut]]||[[File:DhobyGhaut-CCLPlatform.JPG|100px]]||[[File:Aiga escalator down.svg|15px|link=]]&nbsp;{{rbox|North–South Line|North–South MRT line|#{{rcr|SMRT|NS}}|White}}<br />[[File:Aiga escalator down.svg|15px|link=]]&nbsp;{{rbox|North East Line|North East MRT line|#{{rcr|SMRT|NE}}|White}} || rowspan="11" style="text-align:center;"| 17 April 2010;<br />{{Years or months ago|2010|4}} || rowspan=4 | S$343.94 million<br /><ref>{{Cite web|url=http://www.stecs.com.sg/lta-c825|title=Project LTA C825 {{!}} STECS|website=stecs2|language=en|access-date=27 April 2020|archive-date=3 September 2020|archive-url=https://web.archive.org/web/20200903130547/http://www.stecs.com.sg/lta-c825|url-status=live}}</ref><ref>{{Cite web |title=LTA Annual Safety Award Convention 2005 |url=http://www.lta.gov.sg/images/ASAC%20event%20-%20Fact%20sheet%20(FINAL).doc |url-status=dead |archive-url=http://eresources.nlb.gov.sg/webarchives/wayback/20091130045741/http://www.lta.gov.sg/images/ASAC%20event%20-%20Fact%20sheet%20(FINAL).doc |archive-date=30 November 2009 |website=lta.gov.sg}}</ref><ref name="Second contract">{{cite web |title=Award Of Second Civil Works Contract For The Marina Line |url=http://app.lta.gov.sg/corp_press_content.asp?start=312 |website=lta.gov.sg |access-date=2 May 2009 |archive-url=https://eresources.nlb.gov.sg/webarchives/2009-05-01%2016:39:46.000/wp/details/http://app.lta.gov.sg/corp_press_content.asp?start=312 |archive-date=1 May 2009 |date=7 August 2001}}</ref><ref group="note">Stage 1 (CCL1)</ref><ref group="note">Contract 825</ref>
|-
|scope="row"|{{SMRT code|CC|2}}<br />[[File:Aiga escalator down.svg|15px|link=]]&nbsp;[[File:MUTCD D9-6.svg|15px|link=]]||[[Bras Basah MRT station|Bras Basah]]||[[File:Bras Basah MRT Station, 2014 (04).JPG|frameless|100x100px]]||rowspan="2" {{sdash}}
|-
|scope="row"|{{SMRT code|CC|3}}<br />[[File:Aiga escalator down.svg|15px|link=]]&nbsp;[[File:MUTCD D9-6.svg|15px|link=]]||[[Esplanade MRT station|Esplanade]]||[[File:Esplanade-CCLStation.JPG|100px]]
|-
|scope="row"|{{SMRT code|CC|4|DT|15}}<br />[[File:Aiga escalator down.svg|15px|link=]]&nbsp;[[File:MUTCD D9-6.svg|15px|link=]]||[[Promenade MRT station|Promenade]]||[[File:Promenade-CCLPlatform.JPG|100px]]||[[File:Aiga escalator down.svg|15px|link=]]&nbsp;{{rbox|Downtown Line|Downtown MRT line|#{{rcr|SMRT|DT}}|White}}<br> ― <br>[[File:Bus-logo.svg|15px|link=]]&nbsp;<small>Marina Centre</small>
|-
|scope="row"|{{SMRT code|CC|5}}<br />[[File:Aiga escalator down.svg|15px|link=]]&nbsp;[[File:MUTCD D9-6.svg|15px|link=]]||[[Nicoll Highway MRT station|Nicoll Highway]]||[[File:NicollHighway-CCLPlatform.JPG|100px]]|| rowspan="4" {{sdash}} || rowspan=2 | S$573 million<br /><ref>{{Cite web |title=Civil Works Contract Awarded For The Marina Line |url=http://app.lta.gov.sg/corp_press_content.asp?start=263 |url-status=dead |archive-url=https://eresources.nlb.gov.sg/webarchives/2009-05-01%2016:40:03.000/wp/details/http://app.lta.gov.sg/corp_press_content.asp?start=263 |archive-date=1 May 2009 |access-date=23 April 2010 |website=www.lta.gov.sg}}</ref><ref name="CPG Consultants">{{Cite web |title=Marina Mass Rapid Transit (MRT) Line (C824 – Design and Build Tender) |url=https://www.cpgcorp.com.sg/cpgc/Project/Project_Details?ProjectID=732&TypologyID=10 |url-status=live |archive-url=https://web.archive.org/web/20201009120731/https://www.cpgcorp.com.sg/cpgc/Project/Project_Details?ProjectID=732&TypologyID=10 |archive-date=9 October 2020 |access-date=10 October 2020 |website=CPG Consultants}}</ref><ref group="note">Stage 1 (CCL1)</ref><ref group="note">Contracts 824 and 828<br />S$273 million in sunk costs for Contract 824 (pre-[[Nicoll Highway collapse|collapse]])<br />S$300 million for post-collapse works footed by Nishimatsu Construction Co. Ltd.</ref>
|-
|scope="row"|{{SMRT code|CC|6}}<br />[[File:Aiga escalator down.svg|15px|link=]]&nbsp;[[File:MUTCD D9-6.svg|15px|link=]]||[[Stadium MRT station|Stadium]]||[[File:Stadium MRT station 110220.jpg|100px]]
|-
|scope="row"|{{SMRT code|CC|7}}<br />[[File:Aiga escalator down.svg|15px|link=]]&nbsp;[[File:MUTCD D9-6.svg|15px|link=]]&nbsp;[[File:ISO 7010 W003.svg|15px|link=]]||[[Mountbatten MRT station|Mountbatten]]||[[File:Mountbatten-CCLPlatform.JPG|100px]]|| rowspan=3 | S$322 million<br /><ref>{{Cite web|title=Lum Chang - Civil & Infrastructure|url=http://www.lumchang.com.sg/construction/civil-infrastructure/detail/circle-line-(contract-823-828)/|access-date=17 August 2020|website=www.lumchang.com.sg|archive-date=12 October 2020|archive-url=https://web.archive.org/web/20201012115939/http://www.lumchang.com.sg/construction/civil-infrastructure/detail/circle-line-%28contract-823-828%29/|url-status=live}}</ref><ref>{{Cite web|title=CPG Consultants - Circle Line Stage 2 - Geotechnical and Structural Engineering Consultancy Services (Contract 823)|url=https://www.cpgcorp.com.sg/cpgc/Project/Project_Details?ProjectID=911|access-date=17 August 2020|website=www.cpgcorp.com.sg|archive-date=10 July 2021|archive-url=https://web.archive.org/web/20210710185142/https://www.cpgcorp.com.sg/cpgc/Project/Project_Details?ProjectID=911|url-status=live}}</ref><ref>{{Cite web|date=4 February 2009|title=Projects - Rail|url=http://www.lta.gov.sg/projects/proj_rail_ccl2.htm|url-status=live|archive-url=https://web.archive.org/web/20090919121045/http://www.lta.gov.sg/projects/proj_rail_ccl2.htm|archive-date=19 September 2009|website=www.lta.gov.sg}}</ref><ref name="brouchre">{{Cite web|title=Lum Chang Technical Brochure|url=http://www.lumchang.com.sg/docs/default-source/default-document-library/downloads/downloads/lum-chang-technical-brochure.pdf?sfvrsn=2|website=www.lumchang.com.sg|access-date=10 July 2021|archive-date=10 July 2021|archive-url=https://web.archive.org/web/20210710185139/http://www.lumchang.com.sg/docs/default-source/default-document-library/downloads/downloads/lum-chang-technical-brochure.pdf?sfvrsn=2|url-status=live}}</ref><ref group="note">Stage 2 (CCL2)</ref><ref group="note">Contract 823</ref>
|-
|scope="row"|{{SMRT code|CC|8}}<br />[[File:Aiga escalator down.svg|15px|link=]]&nbsp;[[File:MUTCD D9-6.svg|15px|link=]]&nbsp;[[File:ISO 7010 W003.svg|15px|link=]]||[[Dakota MRT station|Dakota]]||[[File:Dakota-CCLPlatform.JPG|100px]]
|-
|scope="row"|{{SMRT code|CC|9|EW|8}}<br />[[File:Aiga escalator down.svg|15px|link=]]&nbsp;[[File:MUTCD D9-6.svg|15px|link=]]||[[Paya Lebar MRT station|Paya Lebar]]||[[File:PayaLebar-CCLPlatform-TopView.JPG|100px]]||[[File:Aiga escalator up.svg|15px|link=]]&nbsp;{{rbox|East–West Line|East–West MRT line|#{{rcr|SMRT|EW}}|White}}
|-
|scope="row"|{{SMRT code|CC|10|DT|26}}<br />[[File:Aiga escalator down.svg|15px|link=]]&nbsp;[[File:MUTCD D9-6.svg|15px|link=]]&nbsp;[[File:ISO 7010 W003.svg|15px|link=]]||[[MacPherson MRT station|MacPherson]]||[[File:MacPherson-CCLPlatform.JPG|100px]]||[[File:Aiga escalator down.svg|15px|link=]]&nbsp;{{rbox|Downtown Line|Downtown MRT line|#{{rcr|SMRT|DT}}|White}} || rowspan=2 | S$356.1 million<br /><ref>{{Cite web|date=4 Feb 2009|title=Projects - Rail|url=http://www.lta.gov.sg/projects/proj_rail_ccl2.htm|url-status=dead|archive-url=https://web.archive.org/web/20090919121045/http://www.lta.gov.sg/projects/proj_rail_ccl2.htm|archive-date=19 September 2009|website=www.lta.gov.sg}}</ref><ref>{{Cite web|title=LTA may replace Circle Line contractor|url=https://www.asiaone.com/News/The+Straits+Times/Story/LTA+may+replace+Circle+Line+contractor.html|access-date=2020-07-18|website=www.asiaone.com|archive-url=https://web.archive.org/web/20200718013113/https://www.asiaone.com/News/The%2BStraits%2BTimes/Story/LTA%2Bmay%2Breplace%2BCircle%2BLine%2Bcontractor.html|archive-date=18 July 2020|url-status=live}}</ref><ref>{{Cite web|last=Yeo|first=Richard|date=2007-09-19|title=Property Highlights of Singapore: Local Firm To Finish 2 Circle Line Stations|url=https://propertyhighlights.blogspot.com/2007/09/local-firm-to-finish-2-circle-line.html|access-date=2020-07-18|website=Property Highlights of Singapore|archive-date=11 July 2021|archive-url=https://web.archive.org/web/20210711010938/https://propertyhighlights.blogspot.com/2007/09/local-firm-to-finish-2-circle-line.html|url-status=live}}</ref><ref group="note">Stage 2 (CCL2)</ref><ref group="note">Contract 822<br />S$338.6 million allocated to original contractors, S$17.5 million for completion works</ref>
|-
|scope="row"|{{SMRT code|CC|11}}<br />[[File:Aiga escalator down.svg|15px|link=]]&nbsp;[[File:MUTCD D9-6.svg|15px|link=]]||[[Tai Seng MRT station|Tai Seng]]||[[File:CC11 Tai Seng MRT Platform.jpg|100px]]||rowspan="2" {{sdash}}
|-
|scope="row"|{{SMRT code|CC|12}}<br />[[File:Aiga escalator down.svg|15px|link=]]&nbsp;[[File:MUTCD D9-6.svg|15px|link=]]&nbsp;[[File:ISO 7010 W003.svg|15px|link=]]||[[Bartley MRT station|Bartley]]||[[File:CC12 Bartley MRT Platforms 20211002 124904.jpg|100px]]|| rowspan="5" style="text-align:center" | 28 May 2009;<br />{{Years or months ago|2009|5}}  || S$63.5 million<ref>{{cite web | title=Projects - Rail | website=www.lta.gov.sg | date=5 Aug 2008 | url=http://www.lta.gov.sg/projects/proj_rail_ccl3.htm | access-date=19 June 2020 | archive-url=https://web.archive.org/web/20090806061832/http://www.lta.gov.sg/projects/proj_rail_ccl3.htm | archive-date=6 August 2009 | url-status=dead }}</ref><ref name="app.lta.gov.sg">{{cite web | title=Award Of Contracts For Stage 3 Of Circle Line| website=www.lta.gov.sg | date=31 July 2003 | url=http://app.lta.gov.sg/corp_press_content.asp?start=805 | access-date=19 June 2020 | archive-url=https://eresources.nlb.gov.sg/webarchives/2008-10-06%2021:52:14.000/wp/details/http://app.lta.gov.sg/corp_press_content.asp?start=805 | archive-date=6 August 2008 | url-status=dead }}</ref>
|-
|scope="row"|{{SMRT code|CC|13|NE|12}}<br />[[File:Aiga escalator down.svg|15px|link=]]&nbsp;[[File:MUTCD D9-6.svg|15px|link=]]&nbsp;[[File:ISO 7010 W003.svg|15px|link=]]||[[Serangoon MRT station|Serangoon]]||[[File:CCL Platform of Serangoon MRT Station.jpg|frameless|99x99px]]||[[File:Aiga escalator down.svg|15px|link=]]&nbsp;{{rbox|North East Line|North East MRT line|#{{rcr|SMRT|NE}}|White}}<br />―<br />[[File:Bus-logo.svg|15px|link=]]&nbsp;<small>[[Serangoon Bus Interchange|Serangoon]]</small>|| S$155.95 million<ref>{{Cite web|title=Project LTA C852|url=http://www.stecs.com.sg/lta-c852|access-date=25 December 2021|website=STECS|language=en|archive-date=4 December 2021|archive-url=https://web.archive.org/web/20211204123056/http://www.stecs.com.sg/lta-c852|url-status=live}}</ref>
|-
|scope="row"|{{SMRT code|CC|14}}<br />[[File:Aiga escalator down.svg|15px|link=]]&nbsp;[[File:MUTCD D9-6.svg|15px|link=]]&nbsp;[[File:ISO 7010 W003.svg|15px|link=]]||[[Lorong Chuan MRT station|Lorong Chuan]]||[[File:CC14 Lorong Chuan MRT Platforms 20211009 124608.jpg|100px]]||{{sdash}}|| S$65.0 million<ref>{{cite web | title=Award Of Contracts For Stage 3 Of Circle Line | website=www.lta.gov.sg | date=27 June 2003 | url=http://app.lta.gov.sg/corp_press_content.asp?start=781 | access-date=19 June 2020 | archive-url=https://eresources.nlb.gov.sg/webarchives/2008-10-06%2021:51:57.000/wp/details/http://app.lta.gov.sg/corp_press_content.asp?start=781 | archive-date=6 October 2008| url-status=dead }}</ref><ref name="Projects - Rail">{{cite web | title=Projects - Rail | website=www.lta.gov.sg | date=5 August 2008 | url=http://www.lta.gov.sg/projects/proj_rail_ccl3.htm | access-date=19 June 2020 | archive-url=https://web.archive.org/web/20090806061832/http://www.lta.gov.sg/projects/proj_rail_ccl3.htm | archive-date=6 August 2009 | url-status=dead }}</ref>
|-
|scope="row"|{{SMRT code|CC|15|NS|17}}<br />[[File:Aiga escalator down.svg|15px|link=]]&nbsp;[[File:MUTCD D9-6.svg|15px|link=]]&nbsp;[[File:ISO 7010 W003.svg|15px|link=]]||[[Bishan MRT station|Bishan]]||[[File:CC15 Bishan MRT Platforms 20201213 144736.jpg|100px]]||[[File:Aiga escalator.svg|15px|link=]]&nbsp;{{rbox|North–South Line|North–South MRT line|#{{rcr|SMRT|NS}}|White}}<br />―<br />[[File:Bus-logo.svg|15px|link=]]&nbsp;<small>[[Bishan Bus Interchange|Bishan]]</small>|| S$82.2 million<ref name="Projects - Rail"/><ref name="app.lta.gov.sg"/><ref>{{cite news |title=$313m Circle Line contracts awarded |work=The Straits Times |date=1 August 2003|page=10}}</ref>
|-
|scope="row"|{{SMRT code|CC|16}}<br />[[File:Aiga escalator down.svg|15px|link=]]&nbsp;[[File:MUTCD D9-6.svg|15px|link=]]||[[Marymount MRT station|Marymount]]||[[File:CC16 Marymount Platform A.jpg|100px]]||{{sdash}}|| S$167.7 million
|-
|scope="row"|{{SMRT code|CC|17|TE|9}}<br />[[File:Aiga escalator down.svg|15px|link=]]&nbsp;[[File:MUTCD D9-6.svg|15px|link=]]&nbsp;[[File:ISO 7010 W003.svg|15px|link=]]||[[Caldecott MRT station|Caldecott]]||[[File:CC17 Caldecott Platform.jpg|frameless|100x100px]]||[[File:Aiga escalator down.svg|15px|link=]]&nbsp;{{rbox|Thomson–East Coast Line|Thomson–East Coast MRT line|#{{rcr|SMRT|TE}}|White}} || style="text-align:center" | 8 October 2011;<br />{{Years or months ago|2011|10}}  || rowspan=4 | S$391.59 million<br /><ref>{{Cite web |title=Award Of Contract For Construction And Completion Of Adam And Farrer Stations |url=http://app.lta.gov.sg/corp_press_content.asp?start=1052 |url-status=dead |archive-url=https://web.archive.org/web/20120906042031/http://app.lta.gov.sg/corp_press_content.asp?start=1052 |archive-date=6 September 2012 |access-date=19 November 2020 |website=www.lta.gov.sg}}</ref><ref group="note">Stage 4 (CCL4)</ref><ref group="note">Contract 854</ref>
|-
|scope="row"|{{SMRT code|CC|18}}<br /><small>''[[Infill station]]''</small><br />[[File:Aiga escalator down.svg|15px|link=]]&nbsp;[[File:MUTCD D9-6.svg|15px|link=]]||''[[Bukit Brown MRT station|Bukit Brown]]''||[[File:CC18 Bukit Brown shell station tunnel 2.jpg|frameless|100x100px]]||{{sdash}}||{{TBA}}
|-
|scope="row"|{{SMRT code|CC|19|DT|9}}<br />[[File:Aiga escalator down.svg|15px|link=]]&nbsp;[[File:MUTCD D9-6.svg|15px|link=]]&nbsp;[[File:ISO 7010 W003.svg|15px|link=]]||[[Botanic Gardens MRT station|Botanic Gardens]]||[[File:CC19 Botanic Gardens MRT Station platform.jpg|100px]]||[[File:Aiga escalator down.svg|15px|link=]]&nbsp;{{rbox|Downtown Line|Downtown MRT line|#{{rcr|SMRT|DT}}|White}} || rowspan="11" style="text-align:center" | 8 October 2011;<br />{{Years or months ago|2011|10}}
|-
|scope="row"|{{SMRT code|CC|20}}<br />[[File:Aiga escalator down.svg|15px|link=]]&nbsp;[[File:MUTCD D9-6.svg|15px|link=]]||[[Farrer Road MRT station|Farrer Road]]||[[File:CC20 Farrer Road Platform level.jpg|100px]]||rowspan="2" {{sdash}}
|-
|scope="row"|{{SMRT code|CC|21}}<br />[[File:Aiga escalator down.svg|15px|link=]]&nbsp;[[File:MUTCD D9-6.svg|15px|link=]]||[[Holland Village MRT station|Holland Village]]||[[File:Interior of Holland Village MRT Station - 20111008.jpg|100px]]|| rowspan=4 | S$399.91 million<br /><ref name="STECS">{{cite web |title=Singapore LTA CCL4 C855 |url=http://www.stecs.com.sg/lta-c855 |website=www.stecs.com |access-date=26 November 2020 |archive-date=26 November 2020 |archive-url=https://web.archive.org/web/20201126124653/http://www.stecs.com.sg/lta-c855 |url-status=live }}</ref><ref>{{cite web |title=Award of Contract for Construction And Completion of Holland, Buona Vista And NUH Stations |url=http://app.lta.gov.sg/corp_press_content.asp?start=1070 |website=www.lta.gov.sg |archive-url=https://web.archive.org/web/20120114163253/http://app.lta.gov.sg/corp_press_content.asp?start=1070 |archive-date=14 January 2012 |url-status=dead |access-date=26 November 2020 }}</ref><ref group="note">Stage 4 (CCL4)</ref><ref group="note">Contract 855</ref>
|-
|scope="row"|{{SMRT code|CC|22|EW|21}}<br />[[File:Aiga escalator down.svg|15px|link=]]&nbsp;[[File:MUTCD D9-6.svg|15px|link=]]&nbsp;[[File:ISO 7010 W003.svg|15px|link=]]||[[Buona Vista MRT station|Buona Vista]]||[[File:Interior of the Circle Line section of Buona Vista MRT Station, Singapore - 20110820.jpg|100px]]||[[File:Aiga escalator up.svg|15px|link=]]&nbsp;{{rbox|East–West Line|East–West MRT line|#{{rcr|SMRT|EW}}|White}}<br> ― <br>[[File:Bus-logo.svg|15px|link=]]&nbsp;<small>[[Buona Vista Bus Terminal|Buona Vista]]</small><br>[[File:Bus-logo.svg|15px|link=]]&nbsp;<small>Ghim Moh</small>
|-
|scope="row"|{{SMRT code|CC|23}}<br />[[File:Aiga escalator down.svg|15px|link=]]&nbsp;[[File:MUTCD D9-6.svg|15px|link=]]||[[one-north MRT station|one-north]]||[[File:CC23 one-north MRT Platforms 20201213 152045.jpg|100px]]||rowspan="6" {{sdash}}
|-
|scope="row"|{{SMRT code|CC|24}}<br />[[File:Aiga escalator down.svg|15px|link=]]&nbsp;[[File:MUTCD D9-6.svg|15px|link=]]||[[Kent Ridge MRT station|Kent Ridge]]||[[File:CC24 Kent Ridge Platform A.jpg|100px]]
|-
|scope="row"|{{SMRT code|CC|25}}<br />[[File:Aiga escalator down.svg|15px|link=]]&nbsp;[[File:MUTCD D9-6.svg|15px|link=]]&nbsp;[[File:ISO 7010 W003.svg|15px|link=]]||[[Haw Par Villa MRT station|Haw Par Villa]]||[[File:CC25 Haw Par Villa MRT Platforms 20220908 091744.jpg|100px]]|| rowspan=5 | S$335 million<br /><ref>{{Cite web |url=http://www.planningplanet.com/users/21292-jenny-azali/view/experience/519147 |title=Senior Planning Engineer, Shimizu, Taisei, SK E&C, Mass Rapit Transit Project - Construction of Station and Tunnel &#124; dedicated to Project Controls |access-date=11 July 2021 |archive-date=30 January 2022 |archive-url=https://web.archive.org/web/20220130083314/http://www.planningplanet.com/users/21292-jenny-azali/view/experience/519147 |url-status=live }}</ref><ref group="note">Stage 5 (CCL5)</ref><ref group="note">Contract 856</ref>
|-
|scope="row"|{{SMRT code|CC|26}}<br />[[File:Aiga escalator down.svg|15px|link=]]&nbsp;[[File:MUTCD D9-6.svg|15px|link=]]||[[Pasir Panjang MRT station|Pasir Panjang]]||[[File:Platform level of Pasir Panjang MRT Station, Singapore - 20111002.jpg|100px]]
|-
|scope="row"|{{SMRT code|CC|27}}<br />[[File:Aiga escalator down.svg|15px|link=]]&nbsp;[[File:MUTCD D9-6.svg|15px|link=]]&nbsp;[[File:ISO 7010 W003.svg|15px|link=]]||[[Labrador Park MRT station|Labrador Park]]||[[File:CC27 Labrador Park Platform B.jpg|100px]]
|-
|scope="row"|{{SMRT code|CC|28}}<br />[[File:Aiga escalator down.svg|15px|link=]]&nbsp;[[File:MUTCD D9-6.svg|15px|link=]]||[[Telok Blangah MRT station|Telok Blangah]]||[[File:CC28 Telok Blangah Platform A.jpg|100px]]
|-
|scope="row"|[[File:MRT Singapore Destination 9.svg|15px]]&nbsp;[[File:MRT Singapore Destination 6.svg|15px]]<br />{{SMRT code|CC|29|NE|1}}<br />[[File:Aiga escalator down.svg|15px|link=]]&nbsp;[[File:MUTCD D9-6.svg|15px|link=]]&nbsp;[[File:ISO 7010 W003.svg|15px|link=]]||[[HarbourFront MRT station|HarbourFront]]||[[File:CC29 Harbourfront MRT Platform B 20210426 173317.jpg|100px]]||[[File:Aiga escalator down.svg|15px|link=]]&nbsp;{{rbox|North East Line|North East MRT line|#{{rcr|SMRT|NE}}|White}}<br />―<br />[[File:Bus-logo.svg|15px|link=]]&nbsp;<small>[[HarbourFront Bus Interchange|HarbourFront]]</small><br />―<br />[[File:BSicon Mono-CHN.svg|10px|link=]]&nbsp;<small>[[Sentosa Express]] [[Sentosa Express#Stations|VivoCity]]</small><br />[[File:BSicon AETRAM.svg|10px|link=]]&nbsp;<small>[[Singapore Cable Car]] Mount Faber Line</small><br />[[File:Aiga watertransportation.svg|10px|link=]]&nbsp;<small>[[HarbourFront Centre]]</small>&nbsp;[[File:Aiga immigration.svg|10px|link=]]<br />[[File:Aiga watertransportation.svg|10px|link=]]&nbsp;<small>[[Singapore Cruise Centre]]</small>&nbsp;[[File:Aiga immigration.svg|10px|link=]]
|-
!colspan=6|Stage 6 <small>''(under construction, to be ready by 1H 2026)''</small>
|-
|scope="row"|{{SMRT code|CC|30}}<br />[[File:Aiga escalator down.svg|15px|link=]]&nbsp;[[File:MUTCD D9-6.svg|15px|link=]]||[[Keppel MRT station|Keppel]]||[[File:CC30 Keppel MRT construction 20201030 155444.jpg|100px]]||rowspan="2" {{sdash}}|| rowspan="3" style="text-align:center" | 1H 2026 || S$313.8 million<br /><ref name="lta.gov.sg">{{Cite web|url=https://www.lta.gov.sg/content/ltagov/en/newsroom/2017/9/2/lta-awards-first-three-civil-contracts-for-circle-line-6.html|archive-url=https://web.archive.org/web/20200305132849/https://www.lta.gov.sg/content/ltagov/en/newsroom/2017/9/2/lta-awards-first-three-civil-contracts-for-circle-line-6.html|url-status=dead|archive-date=5 March 2020|title=LTA {{!}} News Room {{!}} News Releases {{!}} LTA Awards First Three Civil Contracts for Circle Line 6|date=5 March 2020|access-date=5 March 2020}}</ref><ref name="channelnewsasia.com">{{Cite web|url=https://www.channelnewsasia.com/news/singapore/first-circle-line-6-contracts-worth-s-1-75b-awarded-by-lta-9198368|archive-url=https://web.archive.org/web/20200305133756/https://www.channelnewsasia.com/news/singapore/first-circle-line-6-contracts-worth-s-1-75b-awarded-by-lta-9198368|url-status=dead|archive-date=5 March 2020|title=First Circle Line 6 contracts worth S$1.75b awarded by LTA - CNA|date=5 March 2020|access-date=5 March 2020}}</ref><ref>{{Cite web|url=https://www.lta.gov.sg/content/ltagov/en/upcoming_projects/rail_expansion/circle_line_6.html|archive-url=https://web.archive.org/web/20190920030539/https://www.lta.gov.sg/content/ltagov/en/upcoming_projects/rail_expansion/circle_line_6.html|url-status=dead|archive-date=20 September 2019|title=Circle Line 6|language=en|access-date=20 September 2019}}</ref><ref group="note">Contract 882</ref>
|-
|scope="row"|{{SMRT code|CC|31}}<br />[[File:Aiga escalator down.svg|15px|link=]]&nbsp;[[File:MUTCD D9-6.svg|15px|link=]]&nbsp;[[File:ISO 7010 W003.svg|15px|link=]]||[[Cantonment MRT station|Cantonment]]||[[File:CC31_Cantonment_MRT_construction_site_20201030_152717.jpg|100px]]|| S$205 million<br /><ref>{{Cite web|url=https://www.straitstimes.com/singapore/transport/china-state-construction-wins-205m-contract-for-cantonment-mrt-station-on-circle|archive-url=https://web.archive.org/web/20190920031901/https://www.straitstimes.com/singapore/transport/china-state-construction-wins-205m-contract-for-cantonment-mrt-station-on-circle|url-status=dead|archive-date=20 September 2019|title=Circle Line's Cantonment MRT station contract goes to China State Construction for $205m, Transport News & Top Stories - The Straits Times|date=20 September 2019|access-date=20 September 2019}}</ref><ref name="LTA 2017">{{cite web | title=News Room - News Releases - LTA Awards Final Construction Contract for Circle Line 6 | website=LTA | date=10 November 2017 | url=https://www.lta.gov.sg/content/ltagov/en/newsroom/2017/11/2/lta-awards-final-construction-contract-for-circle-line-6.html | access-date=30 October 2020 | archive-date=30 October 2020 | archive-url=https://web.archive.org/web/20201030115010/https://www.lta.gov.sg/content/ltagov/en/newsroom/2017/11/2/lta-awards-final-construction-contract-for-circle-line-6.html | url-status=live }}</ref><ref name="LTA 2020 CCL6">{{cite web | title=Upcoming Projects - Rail Expansion - Circle Line 6 | website=LTA | date=12 June 2020 | url=https://www.lta.gov.sg/content/ltagov/en/upcoming_projects/rail_expansion/circle_line_6.html | access-date=30 October 2020 | archive-date=20 September 2019 | archive-url=https://web.archive.org/web/20190920030539/https://www.lta.gov.sg/content/ltagov/en/upcoming_projects/rail_expansion/circle_line_6.html | url-status=live }}</ref><ref group="note">Contract 883</ref>
|-
|scope="row"|{{SMRT code|CC|32}}<br />[[File:Aiga escalator down.svg|15px|link=]]&nbsp;[[File:MUTCD D9-6.svg|15px|link=]]||[[Prince Edward Road MRT station|Prince Edward Road]]||[[File:CC32 Prince Edward Road MRT construction site 20201030 145716.jpg|100px]]||[[File:Bus-logo.svg|15px|link=]]&nbsp;<small>[[Shenton Way Bus Terminal|Shenton Way]]</small>|| S$310.8 million<br /><ref>{{Cite web|url=https://www.lta.gov.sg/content/ltagov/en/newsroom/2017/10/2/lta-awards-construction-contract-for-circle-line-6-prince-edward-station-and-tunnels.html|archive-url=https://web.archive.org/web/20200305132853/https://www.lta.gov.sg/content/ltagov/en/newsroom/2017/10/2/lta-awards-construction-contract-for-circle-line-6-prince-edward-station-and-tunnels.html|url-status=dead|archive-date=5 March 2020|title=LTA {{!}} News Room {{!}} News Releases {{!}} LTA Awards Construction Contract for Circle Line 6 Prince Edward Station and Tunnels|date=5 March 2020|access-date=5 March 2020}}</ref><ref>{{Cite web|url=https://www.straitstimes.com/singapore/transport/prince-edward-mrt-station-contract-awarded-to-china-railway-tunnel-group|archive-url=https://web.archive.org/web/20200305135058/https://www.straitstimes.com/singapore/transport/prince-edward-mrt-station-contract-awarded-to-china-railway-tunnel-group|url-status=dead|archive-date=5 March 2020|title=Prince Edward MRT station contract awarded to China Railway Tunnel Group, Transport News & Top Stories - The Straits Times|date=5 March 2020|access-date=5 March 2020}}</ref><ref group="note">Contract 885</ref>
|-
!colspan=6|Circle Line extension
|-
|scope="row"|{{SMRT code|CE|1|DT|16}}<br />[[File:Aiga escalator down.svg|15px|link=]]&nbsp;[[File:MUTCD D9-6.svg|15px|link=]]
|[[Bayfront MRT station|Bayfront]]||[[File:CE1 Bayfront Platform B.jpg|100px]]||[[File:Aiga escalator down.svg|15px|link=]]&nbsp;{{rbox|Downtown Line|Downtown MRT line|#{{rcr|SMRT|DT}}|White}} || rowspan="2" style="text-align:center" | 14 January 2012;<br />{{Years or months ago|2012|01}}  || S$463 million<br /><ref group="note">Contract 906; cost shared with DTL</ref>
|-
|scope="row"|[[File:MRT Singapore Destination 10.svg|15px]]<br />{{SMRT code|CE|2|NS|27|TE|20}}<br />[[File:Aiga escalator down.svg|15px|link=]]&nbsp;[[File:MUTCD D9-6.svg|15px|link=]]&nbsp;[[File:ISO 7010 W003.svg|15px|link=]]||[[Marina Bay MRT station|Marina Bay]]||[[File:CE2 Marina Bay Platform A.jpg|100px]]||[[File:Aiga escalator down.svg|15px|link=]]&nbsp;{{rbox|North–South Line|North–South MRT line|#{{rcr|SMRT|NS}}|White}}<br />[[File:Aiga escalator down.svg|15px|link=]]&nbsp;{{rbox|Thomson–East Coast Line|Thomson–East Coast MRT line|#{{rcr|SMRT|TE}}|White}}&nbsp; || S$348.4 million<br /><ref>{{cite web | title=Award Of Contract For CCL Marina Bay Station| website=Land Transport Authority | url=http://app.lta.gov.sg/apps/news/page.aspx?c=2&id=1891 |url-status=dead|archive-url=https://eresources.nlb.gov.sg/webarchives/2013-12-31%2019:07:46.000/wp/details/http://app.lta.gov.sg/apps/news/page.aspx?c=2&id=1891|archive-date=31 December 2013}}</ref><ref name="Home">{{cite web | title=Projects | website=Home | url=https://hlsgroup.com.sg/current-past-track-records.html | access-date=21 April 2020 | archive-date=27 January 2021 | archive-url=https://web.archive.org/web/20210127070006/https://hlsgroup.com.sg/current-past-track-records.html | url-status=live }}</ref><ref name="DTL contract factsheet">{{Cite web|url=https://www.lta.gov.sg/content/dam/ltagov/news/press/2008/2008-11-21_Factsheet_DTL1_Bugis.pdf|title=List of contracts awarded for Downtown Line 1|website=Land Transport Authority|url-status=dead|archive-url=http://eresources.nlb.gov.sg/webarchives/wayback/20151101032615/https://www.lta.gov.sg/data/apps/news/press/2008/2008-11-21_Factsheet_DTL1_Bugis.pdf|archive-date=1 November 2015}}</ref><ref group="note">Contract 901</ref>
|}
The Circle Line's numbering scheme reserves station code "CC18" for future use.

===Depots===
{| class="wikitable" style="border-collapse: collapse; font-size: 95%"
|-
! scope="col" style="color: black; background:#{{rcr|SMRT|Circle}}" | Depot name;<br />Lines
! scope="col" style="color: black; background:#{{rcr|SMRT|Circle}}" | Location
! scope="col" style="color: black; background:#{{rcr|SMRT|Circle}}" | Images
! scope="col" style="color: black; background:#{{rcr|SMRT|Circle}}" | Line-specific<br />stabling capacity
! scope="col" style="color: black; background:#{{rcr|SMRT|Circle}}" | Cost
! scope="col" style="color: black; background:#{{rcr|SMRT|Circle}}" | Opening
|-
| {{rbox|Kim Chuan|Kim Chuan Depot|#{{rcr|SMRT|CC}}|Black}} || [[Hougang]] || [[File:CCL Kim Chuan MRT Depot entrance 20201024 122424.jpg|100px]] || 70 trains&nbsp;<small>''(until 2026)''</small><br />133 trains&nbsp;<small>''(from 2026)''</small> || S$1.507 billion<ref>{{cite news|url=http://www.channelnewsasia.com/stories/singaporelocalnews/view/413013/1/.html|title=World's largest underground depot opens in Singapore|author=Shereena Sajeed|date=4 March 2009|publisher=Channel News Asia|access-date=17 June 2022|archive-date=19 October 2012|archive-url=https://web.archive.org/web/20121019005133/http://www.channelnewsasia.com/stories/singaporelocalnews/view/413013/1/.html|url-status=dead}}</ref><ref>{{Cite web|url=https://www.lta.gov.sg/content/ltagov/en/newsroom/2015/10/2/joint-release-by-the-land-transport-authority-lta-sla---circle-line-6--becoming-a-full-circle.html|archive-url=https://web.archive.org/web/20200305132845/https://www.lta.gov.sg/content/ltagov/en/newsroom/2015/10/2/joint-release-by-the-land-transport-authority-lta-sla---circle-line-6--becoming-a-full-circle.html|url-status=dead|archive-date=5 March 2020|title=LTA {{!}} News Room {{!}} News Releases {{!}} Joint Release by the Land Transport Authority (LTA) & SLA - Circle Line 6 – Becoming A Full Circle|date=5 March 2020|access-date=5 March 2020}}</ref><ref>{{Cite web|url=https://www.straitstimes.com/singapore/transport/biggest-underground-train-depot-set-to-become-even-bigger|archive-url=https://web.archive.org/web/20200305133742/https://www.straitstimes.com/singapore/transport/biggest-underground-train-depot-set-to-become-even-bigger|url-status=dead|archive-date=5 March 2020|title=Biggest underground train depot set to become even bigger, Transport News & Top Stories - The Straits Times|date=5 March 2020|access-date=5 March 2020}}</ref><ref name="lta.gov.sg"/><ref name="channelnewsasia.com"/>{{efn|S$297 million for original construction works, S$1.21 billion for expansion works}} || style="text-align:center" | 4 March 2009;<br />{{Years or months ago|2009|03}}
|}

==Rolling stock==
The [[rolling 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.<ref name="Alstom in Singapore">{{Cite web| url=https://www.alstom.com/sites/alstom.com/files/2018/07/16/country_sheet_singapore_2018_final.pdf| archive-url=https://web.archive.org/web/20191208035114/https://www.alstom.com/sites/alstom.com/files/2018/07/16/country_sheet_singapore_2018_final.pdf| url-status=dead| archive-date=8 December 2019| title=Alstom in Singapore| date=8 December 2019| access-date=8 December 2019|website=Alstom}}</ref> It consists of 40 first-generation [[Alstom Metropolis]] trains were supplied under contract [[Alstom Metropolis C830|C830]].<ref>{{cite speech | url = http://www.news.gov.sg/public/sgpc/en/media_releases/agencies/mot/speech/S-20120504-1/AttachmentPar/0/file/Tuas%20West%20Extension%20Groundbreaking%20Ceremony%20Speech%20on%20040512_media.pdf | title = Tuas West Extension Groundbreaking Ceremony Speech | publisher = Land Transport Authority | date = 4 May 2012 | url-status = dead | archive-url = https://web.archive.org/web/20130929131926/http://www.news.gov.sg/public/sgpc/en/media_releases/agencies/mot/speech/S-20120504-1/AttachmentPar/0/file/Tuas%20West%20Extension%20Groundbreaking%20Ceremony%20Speech%20on%20040512_media.pdf | archive-date = 29 September 2013 }}</ref><ref>[http://app.lta.gov.sg/corp_press_content.asp?start=785 AWARD OF ELECTRICAL & MECHANICAL SYSTEMS CONTRACT 830 FOR THE MARINA line] {{webarchive|url=https://web.archive.org/web/20110527043441/http://app.lta.gov.sg/corp_press_content.asp?start=785 |date=27 May 2011 }}</ref> They are built in [[France]] by [[Alstom]] between 2006 and 2008.<ref name="Alstom in Singapore"/> They are stabled at [[Kim Chuan Depot]], which was the world's largest underground depot when it opened in 2009.<ref>{{Cite web|url=http://www.straitstimes.com/singapore/transport/biggest-underground-train-depot-set-to-become-even-bigger|title=Biggest underground train depot set to become even bigger|website=The Straits Times|date=30 October 2015 |access-date=4 March 2016|archive-url=https://web.archive.org/web/20160310144454/http://www.straitstimes.com/singapore/transport/biggest-underground-train-depot-set-to-become-even-bigger|archive-date=10 March 2016|url-status=live}}</ref> To increase the capacity of the Circle Line, an additional 24 second-generation [[Alstom Metropolis]] trains were supplied under contract [[Alstom Metropolis C830C|C830C]], a similar in design to the first-generation trains, were delivered to Singapore from July 2014.<ref>{{cite web|url=http://app.lta.gov.sg/apps/news/page.aspx?c=2&id=5qmktlgi52sor9rc5r00c6xm8pg371lwhgx5hvtwu8381p6o95 |title=LTA and SMRT Award Contracts for New Trains and Re-Signalling Project |date=1 February 2012 |access-date=16 November 2013 |publisher=Land Transport Authority |url-status=dead |archive-url=https://web.archive.org/web/20130929162504/http://app.lta.gov.sg/apps/news/page.aspx?c=2&id=5qmktlgi52sor9rc5r00c6xm8pg371lwhgx5hvtwu8381p6o95 |archive-date=29 September 2013 }}</ref><ref>{{cite web | url=http://www.alstom.com/press-centre/2012/2/80885/ | title=Alstom to supply 34 Metropolis trains and upgrade signaling on the system | date=3 February 2012 | access-date=16 November 2013 | url-status=dead | archive-url=https://web.archive.org/web/20131231010930/http://www.alstom.com/press-centre/2012/2/80885/ | archive-date=31 December 2013 }}</ref> They are also built in [[Shanghai]], [[China]] by [[Alstom]] between 2014 and 2016.<ref name="Alstom in Singapore"/> 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.<ref>{{Cite web|url=https://www.lta.gov.sg/apps/tender/default.aspx?scr=yes&Ref=851E&scrdate=&fromdate=&todate=&keyword=|title=Tender information {{!}} Land Transport Authority|website=www.lta.gov.sg|language=en|access-date=23 April 2017|archive-url=https://web.archive.org/web/20190715172121/https://www.lta.gov.sg/apps/tender/default.aspx?scr=yes&Ref=851E&scrdate=&fromdate=&todate=&keyword=|archive-date=15 July 2019|url-status=live}}</ref> To increase the capacity of the Circle Line for Circle Line Stage 6, an additional 23 third-generation [[Alstom Metropolis]] trains were supplied under contract [[Alstom Metropolis C851E|C851E]] with the first train set arrived in Singapore on 11 March 2022.<ref>{{cite news |author1=Kok Yufeng |title=New train for Circle Line MRT arrives in Singapore; first of 23 to be shipped here {{!}} The Straits Times |url=https://www.straitstimes.com/singapore/transport/new-train-for-circle-line-mrt-arrives-in-singapore-first-of-23-to-be-shipped-here |access-date=11 March 2022 |work=The Straits Times |date=11 March 2022 |language=en |archive-date=14 March 2022 |archive-url=https://web.archive.org/web/20220314125340/https://www.straitstimes.com/singapore/transport/new-train-for-circle-line-mrt-arrives-in-singapore-first-of-23-to-be-shipped-here |url-status=live }}</ref>

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

==Train control==
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).<ref>{{Cite web|title=Singapore Northeast Line: will soon be the largest, fully automatic metro system in the world|url=http://tsdtemp.turnlav.net/cbtc/projects/SIG_Singapore_AutomaticMetro_en.pdf|url-status=live|archive-url=https://web.archive.org/web/20200615162321/http://tsdtemp.turnlav.net/cbtc/projects/SIG_Singapore_AutomaticMetro_en.pdf|archive-date=15 June 2020|access-date=16 June 2020|pages=4 to 8}}</ref><ref>{{Cite web|title=URBALIS Evolution: Controlling the Performance|url=http://www.sanprotechwriting.com/translation/URBALIS_May14_rev.pdf|url-status=live|archive-url=https://web.archive.org/web/20200615162738/http://www.sanprotechwriting.com/translation/URBALIS_May14_rev.pdf|archive-date=15 June 2020|access-date=16 June 2020|page=4}}</ref> 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.<!--Note:Please do not delete any hidden content in the train control section-->

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.

Automatic [[platform screen doors]] supplied by [[Westinghouse Rail Systems|Westinghouse]] provide safety for commuters, offering protection from arriving and departing trains.<ref>{{cite web |title=Global Project Portfolio |url=http://westinghouse-brakes.com/en/archive/globalprojectportfolio/globalprojectportfolio.jsp |website=westinghouse-brakes.com |archive-url=https://web.archive.org/web/20160827050844/http://westinghouse-brakes.com/en/archive/globalprojectportfolio/globalprojectportfolio.jsp |archive-date=27 August 2016}}</ref>

==Notes and references==

===Notes===
{{notelist}}
{{reflist|group=note}}

===References===
{{reflist|30em}}

==External links==
* {{Commons category-inline}}
* [https://www.lta.gov.sg/content/ltagov/en/getting_around/public_transport/rail_network/circle_line.html Circle line]
* [https://www.lta.gov.sg/content/dam/ltagov/who_we_are/statistics_and_publications/books/pdf/Circle_Line_Book.pdf LTA's commemorative book detailing the construction of the Circle Line]

{{Singapore MRT stations|circle=yes}}
{{Rail transport in Singapore}}
{{Urban Rail Transit in ASEAN}}

{{DEFAULTSORT:Circle MRT line}}
[[Category:Mass Rapid Transit (Singapore) lines]]
[[Category:Railway lines opened in 2009]]
[[Category:Railway loop lines]]
[[Category:2009 establishments in Singapore]]