List of longest subway tunnel sections

This page presents a list of the longest continuous underground rapid transit tunnel sections of the world, excluding branches from the longest tunnel (branch lines that used to transport passengers should be included).

Note: This article only lists tunnels that are 15 km (6.2 miles) or longer.

World's longest subway tunnel sections in use

Name	System	Country	Stations	Length in km (mi)	Year of completion
Lines 3-11	Suzhou Metro	China	Line 3 and Line 11 are connected at Weiting Station with through trains passing by.	86.54 km (53.77 mi)	2019–2023
Line 6	Chengdu Metro	China	Wangcong Temple – Lanjiagou	68.2 (42.4)^[1]	2020
Line 19	Chengdu Metro	China	Huangshi to Tianfu	67 km (42 mi)	2020–2023
Line 1	Qingdao Metro	China	Dongguozhuang to Wangjiagang	59.82 km (37.17 mi)	2020–2021
Line 18	Guangzhou Metro	China	Xiancun^[2] to Wanqingsha	58.3 (36.2)^[2]	2021
Line 3	Guangzhou Metro	China	Airport North – Panyu Square	57.93 (36)	2005–2018
Bolshaya Koltsevaya line	Moscow Metro	Russia	Circle route	57.54 km (35.75 mi)^[3]^[4] (excluding Moscow-City branch)	2018–2023^[5]
Line 10	Beijing Subway	China	Circle route	57.1 (35.5)	2008–2013
Line 6	Beijing Subway	China	Jin'anqiao – Lucheng	53.4 (33.2)	2012–2018
Seoul Subway Line 5 (longest branch)	Seoul Subway	South Korea	Banghwa–Hanam Geomdansan	51.7 km (32.1 mi)	1995–2021
M11	Istanbul Metro	Turkey	Gayrettepe – Arnavutköy Hastane	51.5 (32)	2023–2024
Line 2	Wuhan Metro	China	Julong Boulevard - Fozuling	50.347 (27.556)	2012–2019
Arbatsko-Pokrovskaya line	Moscow Metro	Russia	Pyatnitskoye Shosse – Shchyolkovskaya	45.1 (28.0)	1938–2012
Sokolnicheskaya line	Moscow Metro	Russia	Kommunarka – Bulvar Rokossovskogo	44.5 (27.7)	1935–2019
Lyublinsko-Dmitrovskaya line	Moscow Metro	Russia	Zyablikovo – Fiztekh	44.3 (27.5)	1995–2023
Zamoskvoretskaya line	Moscow Metro	Russia	Khovrino – Alma-Atinskaya	42.8 (26.6)	1938–2018
Line 8	Beijing Subway	China	Yuzhi Lu – Wufutang	42.6 (26.4)	2012–2021
Line 15	Shanghai Metro	China	Gucun Park – Zizhu Hi-tech Park	42.3 (26.3)	2021
Line 5	Chengdu Metro	China	Jiudaoyan – Huilong	42.3 (26.3)	2019
Tagansko-Krasnopresnenskaya line	Moscow Metro	Russia	Planernaya – Kotelniki	42.2 (26.2)	1966–2015
Line 14	Beijing Subway	China	Dawayao – Shangezhuang	42 (26)	2015–2021
Line 6	Tianjin Metro	China	Nanhezhuang – Lushuidao	42 (26)	2016–2021
Downtown MRT line	Mass Rapid Transit (Singapore)	Singapore	Bukit Panjang – Expo	41.9 (26)^[6]	2013–2017
Line 3	Nanjing Metro	China	Xinghuolu – Mozhoudonglu	41.5 (25.8)	2015
Line 4	Suzhou Metro	China	Longdaobang — Tongli	41.5 (25.8)	2017
Serpukhovsko-Timiryazevskaya line	Moscow Metro	Russia	Altufyevo – Bulvar Dmitriya Donskogo	41.2 (25.6)	1983–2002
L-12 (Metro Sur)	Madrid Metro	Spain	Circle route	40.96 (25.5)	2003
Toei Oedo Line ^[citation needed]	Toei Subway	Japan	Hikarigaoka – Shiodome – Tocho-mae	40.7 (25.3)	2000
Seoul Subway Line 9	Seoul Subway	South Korea	Gimpo Airport – VHS Medical Center	40.6 (25.2)	2018
Line 12	Shanghai Metro	China	Qixin Road – Jinhai Road	40.4 (25.1)	2015
Line 7	Beijing Subway	China	Beijing West railway station - Universal Resort	40.3 (25.0)	2021
Line 4	Chengdu Metro	China	Wansheng – Chengdu University	39.3 (24.4)	2015–2017
Line 7	Chengdu Metro	China	Circle route	38.6 (24.0)	2017
Kaluzhsko-Rizhskaya line	Moscow Metro	Russia	Medvedkovo – Novoyasenevskaya	37.8 (23.5)	1958–1990
Line 1	Chengdu Metro	China	Weijianian – Science City	37.47 (23.3)	2010–2018
Line 2	Shenzhen Metro	China	Chiwan – Xinxiu	35.78 (22.23)	2011
Busan Subway Line 2	Busan Transportation Corporation	South Korea	Jangsan–Dongwon	35.5 (22.06)	1999
Seoul Subway Line 6	Seoul Subway	South Korea	Eungam Loop – Bonghwasan	35.1 (21.8)	2001
Seoul Subway Line 7 (longest branch)	Seoul Subway	South Korea	Cheongdam – Bupyeong-gu Office	35.1 (21.7)	2012
Line 5	Tianjin Metro	China	Beichenkejiyuanbei – Liqizhuangnan	34.8 (21.6)	2018–2021
Line 7	Shanghai Metro	China	Panguang Road – Huamu Road	34.4 (21.38)	2010
Line 8	Guangzhou Metro	China	Wanshengwei—Jiaoxin	33.9 (21.1)	2010–2020
M4	Istanbul Metro	Turkey	Kadıköy – Sabiha Gökçen Havalimanı	33.5 (20.8)	2012–2022
Circle MRT line	Mass Rapid Transit (Singapore)	Singapore	Dhoby Ghaut – HarbourFront	33.3 (20.69)^[7]	2009–2012
L-7	Madrid Metro	Spain	Hospital del Henares – Pitis	32.9 (20.5)	2007
U7	Berlin U-Bahn	Germany	Rathaus Spandau-Rudow	31.8 (19.7)^[8]	1924–1984
Line 1	Beijing Subway	China	Pingguoyuan – Dawang Lu	31.0 (19.3)	1971–2000
Line 16	Beijing Subway	China	Bei'anhe – Yuyuantan East Gate	31.0 (19.2)	2016–2021
Solntsevskaya line	Moscow Metro	Russia	Aeroport Vnukovo – Delovoy Tsentr	30.9 (19.2)	2014–2023
IND Eighth Avenue Line and IND Fulton Street Line^[9]	New York City Subway	United States	Inwood – 207th Street – Grant Avenue	30.8 (19.14)	1956
Line 2 Orange	Montreal Metro	Canada	Côte-Vertu – Montmorency	30.8 (19.14)	2007
Thomson–East Coast line	Mass Rapid Transit (Singapore)	Singapore	Woodlands North – Gardens by the Bay	30.4 km (18.9 mi)	2020–2022
Line 2	Shanghai Metro	China	East Xujing – Longyang Road	30.2 (18.77)	2010
Moskovsko-Petrogradskaya Line	Saint Petersburg Metro	Russia	Parnas–Kupchino	30.1 (18.7)	1961–2006
Line 8	Shanghai Metro	China	Shiguang Road – Luheng Road	29.7 (18.45)	2009
Kirovsko-Vyborgskaya Line	Saint Petersburg Metro	Russia	Devyatkino – Prospekt Veteranov	29.57 (18.4)	1955–1978
Line 8	Chengdu Metro	China	(Phase 2 is 7.94 km)	29.1 (18.1)	2020
Line 2	Chengdu Metro	China	Tianhe Road – Chengdu Institute of Public Administration	29.0 (18.0)	2012–2013
Bannan Line (Taipei Metro Blue Line)	Taipei Metro	Taiwan	Dingpu – Taipei Nangang Exhibition Center	28.2 (17.6)	1999–2015
Line 4	Beijing Subway	China	Anheqiao Bei (N) – Gongyi Xiqiao	28.2 (17.5)	2009–2010
Incheon Subway Line 1	Incheon Subway	South Korea	Bakchon – International Business District	27.9 (17.42)	1999–2009
Northern line	London Underground	United Kingdom	Morden – East Finchley	27.8 (17.2)	1890–1940
Nevsko-Vasileostrovskaya Line	Saint Petersburg Metro	Russia	Begovaya–Rybatskoye	27.7 (17.2)	1967–2018
Tanimachi Line	Osaka Metro	Japan	Dainichi–Nagahara	27.1 (16.7)	1967–1983
M5	Istanbul Metro	Turkey	Üsküdar – Samandıra Merkez	26.5 (12.5)	2017–2024
Meijo Line ^[citation needed]	Nagoya Municipal Subway	Japan	Kanayama–Nagoya Dome-mae Yada-Kanayama	26.4 (16.4)	1965–2004
B Line	Los Angeles Metro Rail	United States	North Hollywood - Union Station	26.4 (16.4)	1993–2000
Frunzensko-Primorskaya Line	Saint Petersburg Metro	Russia	Komendantsky Prospekt – Shushary	26.2 (16.3)	1997–2019
Line 1	Suzhou Metro	China	Mudu – Zhongnan Jie	25.7 (16.0)	2012
Line 3^[10]	Athens Metro	Greece	Dimotiko Theatro – Doukissis Plakentias	25.3 (15.72)	2023
Helsinki Metro	Helsinki Metro	Finland	Kalasatama – Kivenlahti	25.2 (15.7)	1982–2022
Orange Line	Taipei Metro	Taiwan	Huilong–Nanshijiao	25.1 (15.6) (longest branch)	1998–2013
Line 3	Santiago Metro	Chile	Plaza de Quilicura - Fernando Castillo Velasco	25 (13.5)	2019–2023
Yurakucho Line	Tokyo Metro	Japan	Chikatetsu Narimasu – Tatsumi	24.6 (15.3)	1974–1988
U2	Munich U-Bahn	Germany	Feldmoching – Messestadt Ost	24.4 (15.2)	1980–2001
Yellow Line	Delhi Metro	India	GTB Nagar – Saket	24 (14.9)^[11]^[12]	2009–2010
L-1	Madrid Metro	Spain	Valdecarros – Pinar de Chamartín	23.88 (14.84)	1919–2007
L-6	Madrid Metro	Spain	Circle route	23.47 (14.58)	1979–2007
Line 9	Shanghai Metro	China	Jiuting – Middle Yanggao Road	23.3 (14.48)	2007–2010
Line 1 Green	Montreal Metro	Canada	Angrignon – Honoré-Beaugrand	23.26 (14.45)	1966–1978
Warsaw Metro M1	Warsaw Metro	Poland	Kabaty–Młociny	23.1 (14.35)	1995–2008
Line 2	Beijing Subway	China	Circle route	23.1 (14.35)	1984–1987
M3	Istanbul Metro	Turkey	Bakırköy Sahil – Şehir Hastanesi Viaduct	22.6 (16.6)	2013–2024
Line 9	Chengdu Metro	China	Phase 1 of the second loop line in Chengdu, all underground	22.18 km (13.78 mi)	2020
Line 19	Beijing Subway	China	Mudanyuan – Xingong	22.4 (13.9)	2021
Songshan-Xindian Line (Taipei Metro Green Line)	Taipei Metro	Taiwan	Songshan-Xindian	21.3 (13.2)	1998–2014
Line 4	Shanghai Metro	China	Hailun Road – Yishan Road	21.1 (13.11)	2005–2007
Toei Mita Line	Toei Subway	Japan	Meguro – Shimura-Sakaue	21.1 (13.11)	1968–2000
Victoria line	London Underground	United Kingdom	Walthamstow Central – Brixton	21.0 (13.05)	1968–1971
Obolonsko–Teremkivska line	Kyiv Metro	Ukraine	Heroiv Dnipra–Teremky	20.95 (13.02)	1976–2013
Line 6	Shanghai Metro	China	Boxing Road – Oriental Sports Center	20.34 (12.64)	2007–2011
Line 1	Barcelona Metro	Spain	Fondo – Hospital de Bellvitge	20.2 (12.56)	1926–1989
Tozai Line ^[citation needed]	Sapporo Municipal Subway ^[citation needed]	Japan	Miyanosawa – Shin-Sapporo ^[citation needed]	20.1 (12.4)	1976–1999
M1	Ankara Metro	Turkey	Koru – Atatürk Kültür Merkezi	20.1 (12.4)	1997–2014
L-5	Madrid Metro	Spain	Alameda de Osuna – Empalme	20.005 (12.5)	1968–2006
Line 9	Barcelona Metro	Spain	Zona Universitaria – Aeroport T1	20.0 (12.5)	2004–2016
North East MRT line	Mass Rapid Transit (Singapore)	Singapore	HarbourFront–Punggol	20.0 (12.43)^[13]	2003–2011
Bucharest Metro Line M3	Bucharest Metro	Romania	Preciziei – Anghel Saligny	20.0 (12.43)	1983–2008
Line 2	Tianjin Metro	China	Caozhuang – Guoshanlu	19.7 (12.2)	2012–2014
Nekrasovskaya line	Moscow Metro	Russia	Nizhegorodskaya – Nekrasovka	19.6 (12.2)	2019–2020
Paris Métro Line 9	Paris Métro	France	Pont de Sèvres – Mairie de Montreuil	19.6 (12.18)	1922–1937
M2	Istanbul Metro	Turkey	Şişhane – Hacıosman Line is 23,49 km long, but the longest continuous underground section is 19.54 km long.	19.54 (12.14)	2000–2014
Red, Yellow, Blue, and Green Lines	Bay Area Rapid Transit, San Francisco	United States	Balboa Park – West Oakland	19.5 (12.12)	1973
Metro Northwest	Sydney Metro	Australia	Cherrybrook–Chatswood	19.5 km (12.1 mi)	2009–2019
Kol'tsevaya Line	Moscow Metro	Russia	Circle route	19.4 (12.2)	1950–1954
U3	Munich U-Bahn	Germany	Moosach – Fürstenried West	19.4 (12.05)	1972–2009
Line 4	Tianjin Metro	China	Dongnanjiao – Xinxingcun	19.4 (12)	2021
Line 3	Tianjin Metro	China	Huayuan – Tianshili	19.2 (11.9)	2012–2013
Maskoŭskaja line	Minsk Metro	Belarus	Malinawka–Uruchcha	19.1 (11.9)	1984–2014
Midosuji Line	Osaka Metro	Japan	Nakatsu – Nakamozu	19.1 (11.87)	1933–1987
Line 5	Barcelona Metro	Spain	Vall d'Hebron – Cornella centre	19.0 (11.8)	1955–2010
Warsaw Metro M2	Warsaw Metro	Poland	Bemowo–Bródno	18.9 km (11.7 mi)	2015–2022
Mexico City Metro Line 3	Mexico City Metro	Mexico	La Raza – Universidad	18.7 (11.62)	1970–1983
Paris Métro Line 7	Paris Métro	France	La Courneuve – 8 Mai 1945 – Villejuif – Louis Aragon	18.3 (11.6)	1910–1987
Red Line	Baku Metro	Azerbaijan	Icheri Sheher – Hazi Aslanov	18.6 (11.6)	1967–2002
Line 3	Barcelona Metro	Spain	Zona Universitària – Trinitat Nova	18.4 (11.44)	1925–2008
Line 1	Shanghai Metro	China	Shanghai South Railway – Shanghai Circus World	18.1 (11.25)	1993–2004
Avtozavodskaya Line	Minsk Metro	Belarus	Kamennaya Gorka – Mogilevskaya	18.1 (11.25)	1990–2005
U8	Berlin U-Bahn	Germany	Wittenau – Hermannstraße	18.1 (11.25)	1927–1996
Line B	Prague Metro	Czechia	Rajská zahrada – Hůrka	18.0 (11.2)	1998
Line 2^[10]	Athens Metro	Greece	Anthoupoli – Elliniko	17.9 (11.12)	2013
Line 5	Beijing Subway	China	Huixin Xijie Beikou – Songjiazhuang	17.8 (11.1)	2007
Washington, DC Metro Red Line	Washington Metro	United States	Union Station – Medical Center	17.8 (11.05)	1984
Line 15	Beijing Subway	China	Qinghua Donglu Xikou – Maquanying	17.6 (10.9)	2014
Tozai Line	Kyoto Municipal Subway	Japan	Uzumasa Tenjingawa-Yamashina-Rokujizo	17.5 (10.92)	2008^[page needed]
Line 4	Barcelona Metro	Spain	Trinitat Nova – La Pau	17.3 (10.76)	1908^[clarification needed]–1999
Kholodnohirsko–Zavodska line	Kharkiv Metro	Ukraine	Kholodna Hora – Industrialna	17.3 (10.7)	1975–1978
Milan Metro M3	Milan Metro	Italy	Comasina – San Donato	17.105 (10.62)	1990–2011
Bucharest Metro Line M2	Bucharest Metro	Romania	Pipera – Berceni	17.1 (10.62)	1986–1987
Tōzai Line	Tokyo Metro	Japan	Nakano–Minami-Sunamachi	17.0 (10.56)	1969
M1	İzmir Metro	Turkey	Kaymakamlık – Basmane Line is 27 km long, but only 19.8 km of it is underground in two noncontinuous sections. The shorter underground section is 2.9 km long.	16.9 (10.5)	2000–2024
Hanzomon Line	Tokyo Metro	Japan	Shibuya-Oshiage	16.8 (10.4)	1978–2003
Mexico City Metro Line 1	Mexico City Metro	Mexico	Observatorio – Pantitlán	16.7 (10.38)	1984
Blue Line	Chennai Metro	India	Saidapet - Tondiarpet	16.6 (10.32)	2018–2021
Line 9	Beijing Subway	China	National Library – Guogongzhuang	16.5 (10.3)	2012
Line 17	Beijing Subway	China	Shilihe – Jiahuihu	16.5 (10.3)	2021
L-3	Madrid Metro	Spain	Villaverde Alto – Moncloa	16.42 (10.2)	2007
Line 1	Chongqing Rail Transit	China	Chaotianmen – Shapingba	16.4 (10.2)	2011
Line A	Prague Metro	Czechia	Nemocnice Motol – Depo Hostivař Line is 17.1 km long, but only 16.4 km of it is underground.	16.4 (10.2)	2015
Kalininskaya line	Moscow Metro	Russia	Tretyakovskaya – Novokosino	16.3 (10.1)	1979–2012
L-4	Madrid Metro	Spain	Argüelles – Pinar de Chamartín	16.0 (9.9)	2007
Sviatoshynsko–Brovarska line	Kyiv Metro	Ukraine	Akademmistechko–Dnipro	16.0 (9.9)	1960–2003
Seoul Subway Line 7 (shorter section)	Seoul Subway	South Korea	Suraksan – Konkuk University	16.0 (9.9)	1996
U6	Berlin U-Bahn	Germany	Alt-Mariendorf – Kurt-Schumacher-Platz	15.9 (9.86)	1923–1966
M9	Istanbul Metro	Turkey	Ataköy – Olimpiyat Viaduct	15.8 (10.7)	2013–2024
M3 Line	Copenhagen Metro	Denmark	Circle route	15.5 km (9.6 mi)	2019
Line 3^[14]	Budapest Metro	Hungary	Határ út–Újpest-központ Line is 17.39 km long, but only 15.5 km of it is underground.	15.5 km (9.6 mi)	1990
Line 1	Tianjin Metro	China	Qinjiandao – Tucheng	15.37 (9.55)	2006
Line 6	Santiago Metro	Chile	Cerrillos – Los Leones	15.3 (9.5)	2017
Paris Métro Line 12	Paris Métro	France	Front Populaire – Mairie d'Issy	15.3 (9.5)	1910–2012
Syretsko–Pecherska line	Kyiv Metro	Ukraine	Syrets – Pivdennyi Bridge	15.2 (9.4)	1989–2004
Line 1 (Kolkata Metro)	Kolkata Metro	India	Mahanayak Uttam Kumar -Dum Dum	15.17 (9.38)	1984–1995
Line 10	Chengdu Metro	China	Taipingyuan – Shuangliu West Station	15.0 (9.32)	2019
Island line	MTR	Hong Kong	Kennedy Town^[15] – Heng Fa Chuen	15.0 (9.32)	1985 (as   Hong Kong)–2014

World's longest subway tunnel sections under construction

Name	System	Country	Stations	Length	Expected completion
Ligne 15	Paris Métro	France	Circle route, all underground	75 km (47 mi)	2025–2030
M11	Istanbul Metro	Turkey	(Phase 2, Kargo Terminali - Halkalı section is 31.5 km in length and is currently under construction, all underground)	69 km (43 mi)	Phase 2：2024
Cross Island line	Mass Rapid Transit (Singapore)	Singapore	Linear route with branch section, all underground (Excludes potential extension from Punggol to Seletar Airport under planning)	65.5 km (40.7 mi)	2030–2032
Line 13	Guangzhou Metro	China	Whole lines is underground (includes Phase II: Chaoyang – Zhucun is 33.6 km and under construction)	59.2 km (36.8 mi)	Phase 1：2017 Phase 2：2024 and later
Line 13	Shenzhen Metro	China	Whole line is underground	45.72 km (28.41 mi)	Phase 1：2024 Phase 2 (North extension)：2025 South extension：2026
L9 / L10	Barcelona Metro	Spain		43.7 km (27.2 mi) (incl. branches)	2009 and 2016 partially; central section unknown
Thomson–East Coast line	Mass Rapid Transit (Singapore)	Singapore	Woodlands North to Sungei Bedok (Phases 4 and 5, Gardens by the Bay – Sungei Bedok are 13 km in length and are currently under construction, all underground)	43.4 km (27.0 mi)	Phase 4：2024 Phase 5：2025
Line 11	Guangzhou Metro	China	Circle route, all underground	43.2 km (26.8 mi)	2024
Troitskaya line	Moscow Metro	Russia	Whole line is underground	40.2 km (25.0 mi)	Phase 1：2024 (25 km (16 mi)) Phase 2：2028–2029 (15.2 km (9.4 mi))
Athens Metro Line 4	Athens Metro			38.2 km (23.7 mi)^[16]	2029 for Phase 1^[17]
Metro Manila Subway	Manila Metro Rail Transit System	Philippines	Mindanao Avenue – Ninoy Aquino International Airport (All underground)	36 km (22 mi)	2029
Line 3	Mumbai Metro	India	Cuffe Parade-SEEPZ	33.02 km (20.52 mi)	2024 for Phase 1
Line 13	Chengdu Metro	China	Qiligou – Longhua Temple underground section	29.07 km (18.06 mi)	2024
Line 3	Chennai Metro	India	Madhavaram Milk Colony – Tharamani	27.086 km (16.830 mi)	2026–2027
D Line Extension	Los Angeles Metro	United States	Westwood/VA Hospital – Union Station	24.3 km (15.1 mi)	2025–2026
Line 30	Chengdu Metro	China	(Phase 1 is 26.28 km)	26.28 km (16.33 mi)	2024
Suburban Rail Loop	Melbourne rail network	Australia	SRL East and North is underground (Cheltenham to Airport)	26 km (16 mi)	2035^[18] (Eastern stretch)
Metro West	Sydney Metro	Australia		24 km (15 mi)	2032^[19]
Metro Western Sydney Airport	Sydney Metro	Australia		23 km (14 mi)	2026
Blue Line	Stockholm Metro	Sweden	The extension to Nacka will be around 8 km, all underground, total 22 km including older sections.	22 km (14 mi)	2030
Line 27	Chengdu Metro	China	Whole line is 24.86 km, but only 17.34 km underground	17.34 km (10.77 mi)	2024
Metro City & Southwest	Sydney Metro	Australia	Chatswood – Sydenham	16 km (9.9 mi)	2024^[20]

See also

• List of longest tunnels
• List of long tunnels by type
• List of longest railway tunnels
• List of long railway tunnels in China

References

1. "独家探访|关于西部最长地铁6号线，你想知道的一切都在这里". 9 September 2020. 成都地铁6号线全长68.76千米，共设有56座车站
2. . 金羊网. 20 February 2021. Archived from the original on 10 April 2021. Retrieved 10 April 2021. 广州市2021年十件民生实事显示，2021年广州将力争开通试运营地铁18号线先通段（万顷沙-冼村，58.3公里）、22号线先通段（番禺广场-陈头岗，18.2公里）
3. "Не 70 км, а 57,5! Как московские власти "удлинили" Большую кольцевую линию метро". 22 March 2023.
4. "IMG 20230327 063939 969 — Postimages".
5. First stretch opens in 1969 as part of line 2
6. "Downtown Line 3 officially opens; Khaw Boon Wan announces review of fares incurred when switching between stations". The Straits Times. 20 October 2017. Retrieved 13 June 2019.
7. "Factsheet on Circle Line Extension". www.lta.gov.sg. 28 November 2011. Retrieved 13 June 2019.
8. "World's longest railway tunnel" 1984–1988
9. Note that both lines are served continuously by the A train within a single tunnel.
10. "Urban Rail Transport SA :METRO Line 1". Retrieved 30 September 2014.
11. "Metro to bridge Delhi-Gurgaon divide today". The Hindu. Chennai, India. 3 September 2010. Retrieved 19 October 2010.
12. Rajesh Ahuja (29 August 2010). "Gurgaon Metro set for operationalisation next week". Retrieved 19 October 2010.
13. "North East Line". www.lta.gov.sg. Retrieved 13 June 2019.
14. "3-as metróvonal jellemzői". Metros.hu (in Hungarian). Retrieved 27 March 2016.
15. Including 0.4 miles/0.65 km of overrun tunnel to the west of Kennedy Town station. - Gammon. "MTR West Island Line - Sai Ying Pun; Hong Kong University and Kennedy Town Stations - Project details". - CIHT Hong Kong Branch. "West Island Line, Contact 705, KET Station & Overrun Tunnel" (PDF).
16. (PDF). Archived from the original (PDF) on 21 September 2022.
17. "Μετρό-Γραμμή 4: Ξεκινούν τα έργα - Οι 15 σταθμοί από Γαλάτσι έως Γουδί - Έτοιμο σε 8 χρόνια". www.naftemporiki.gr (in Greek). 22 June 2021. Retrieved 20 May 2022.
18. "Works Start Today on Victoria's Suburban Rail Loop | Premier of Victoria".
19. https://www.nsw.gov.au/media-releases/metro-west-to-supercharge-housing-supply
20. https://www.nsw.gov.au/media-releases/sydenham-bankstown-metro