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List of long tunnels by type
List of long tunnels by type
List of long tunnels by type
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This page presents the same tunnels as in list of tunnels by length in separate lists according to the different tunnel types.

Rail

[edit]
Main article: List of longest railway tunnels

Note: This list only contains tunnels that are longer than 25 km (16 mi).

Name Location Length Year Line
Gotthard Base Tunnel Switzerland (Alps) 57.1 km (35.5 mi) 2016
Seikan Tunnel Japan (Tsugaru Strait) 53.9 km (33.5 mi) 1988 Kaikyo Line (Hokkaidō Shinkansen)
Channel Tunnel France/United Kingdom (English Channel) 50.5 km (31.4 mi) 1994
Yulhyeon Tunnel South Korea (Gyeonggi) 50.3 km (31.3 mi)[1] 2016[2] Suseo High Speed Railway
Songshan Lake Tunnel[3] China (Dongguan) 35.4 km (22.0 mi) 2016 Dongguan–Huizhou Intercity Railway
Lötschberg Base Tunnel Switzerland (Bernese Alps) 34.5 km (21.4 mi) 2007
Koralm Tunnel Austria (Koralpe) 32.9 km (20.4 mi) 2025 Koralm Railway
New Guanjiao Tunnel China (Qinghai) 32.6 km (20.3 mi)[a] 2014 Qinghai–Tibet Railway
Guadarrama Tunnel[4] Spain (Sierra de Guadarrama) 28.4 km (17.6 mi) 2007 LAV Madrid - Valladolid
West Qinling Tunnel China (Gansu) 28.2 km (17.5 mi)[a] 2016 Qinghai–Tibet Railway
Taihang Tunnel[5] China (Shanxi)
  • 27.8 km (17.3 mi)
  • 27.8 km (17.3 mi)[a]
 2007 Shijiazhuang–Taiyuan High-Speed Railway
Hakkōda Tunnel Japan (Hakkōda Mountains) 26.5 km (16.5 mi) 2010 Tōhoku Shinkansen
XRL Hong Kong (New Territories and Kowloon) 26 km (16.2 mi) 2018 Guangzhou-Shenzhen-Hong Kong Express Rail Link Hong Kong Section[b]
Iwate-Ichinohe Tunnel Japan (Ōu Mountains) 25.8 km (16.0 mi) 2002 Tōhoku Shinkansen
  1. ^ a b c 2 tubes
  2. ^ A further 4 km (2.5 mi) on the opposite side of the Hong Kong-China border.

Under construction

[edit]

Note: This list only contains tunnels that are longer than 25 km (16 mi).

Name Location Length Expected
completion 		Line
Mont d'Ambin base tunnel[6] France/Italy (Cottian Alps) 57.5 km (35.7 mi) 2029[7] Lyon Turin Ferroviaire
Brenner Base Tunnel Austria/Italy (Stubai Alps) 55 km (34.2 mi) 2028[8] Brenner Railway
Yigong Tunnel [zh] 易贡隧道[9][10] China (Tibet) 42.5 km (26.4 mi) 2030 Nyingchi–Ya'an railway
Sejila Mountain Tunnel [zh] 色季拉山隧道[9][10] China (Tibet) 37.9 km (23.5 mi) 2030 Nyingchi–Ya'an railway
Metropolitan Area Tunnel No. 1[11] Japan (Tokyo) 37.168 km (23.1 mi) 2027+ Chūō Shinkansen
Pearl River Tunnel 珠江隧道[12] China (Guangdong) 36.043 km (22.4 mi) 2021 Guangzhou–Foshan circular intercity railway
Duomuge Tunnel 多木格隧道[9] China (Tibet) 36 km (22.4 mi) 2030 Nyingchi–Ya'an railway
Gaoligongshan Tunnel China (Yunnan) 34.5 km (21.5 mi) 2022 Dali-Ruili Railway
Chukyo Area Tunnel No.1[11] Japan (Aichi) 34.210 km (21.3 mi) 2027+ Chūō Shinkansen
Oshima Tunnel Japan (Hokkaido) 32.675 km (20.3 mi) 2031 Hokkaidō Shinkansen
Mangkangshan Tunnel China (Tibet) 29.4 km (18.3 mi) 2026 Kangding-Linzhi Railway
Ping'an Tunnel China (Sichuan)
  • 28.4 km (17.6 mi)
  • 28.2 km (17.5 mi)[a]
 2023 Chengdu–Lanzhou Railway
Semmering Base Tunnel Austria (Raxalpe) 27.3 km (17.0 mi) 2027[13] Southern Railway
Valico Tunnel [Wikidata] Italy (Liguria, Piedmont) 27.250 km (16.9 mi) 2023 Tortona–Genoa high-speed railway
Sasson Tunnel Japan (Hokkaido) 26.2 km (16.3 mi) 2031 Hokkaidō Shinkansen
Musil Tunnel South Korea (Wonju) 25.1 km (15.6 mi) 2020[needs update] Jungang Line
Minshan Tunnel China (Sichuan) 25.0 km (15.6 mi) 2023 Chengdu–Lanzhou Railway
Southern Alps Tunnel [ja][11] Japan (Nagano, Shizuoka, Yamanashi) 25.019 km (15.5 mi) 2027+ Chūō Shinkansen
  1. ^ 2 tubes

Underground rapid transit

[edit]
Main article: List of longest subway tunnel sections

Only continuous tunnel sections should be included, at least 42 km (26 mi) long, excluding branches from the longest tunnel.

Name System Country Stations Length Year
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
M11 Istanbul Metro Turkey Gayrettepe – Halkalı 69 km (43 mi) 2023–2025
Line 6 Chengdu Metro China Wangcong Temple – Lanjiagou 68.2 km (42.4 mi)[14] 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[15] to Wanqingsha 58.3 km (36.2 mi)[15] 2021
Line 3 Guangzhou Metro China Airport North – Panyu Square 57.93 km (36.00 mi) 2005–2018
Bolshaya Koltsevaya line Moscow Metro Russia Circle route 57.54 km (35.75 mi)[16][17]
(excluding Moscow-City branch) 		2018–2023[18]
Line 10 Beijing Subway China Circle route 57.1 km (35.5 mi) 2008–2013
Line 6 Beijing Subway China Jin'anqiao – Lucheng 53.4 km (33.2 mi) 2012–2018
Seoul Subway Line 5
(longest branch) 		Seoul Subway South Korea Banghwa–Hanam Geomdansan 51.7 km (32.1 mi) 1995–2021
Line 2 Wuhan Metro China Julong Boulevard - Fozuling 50.347 km (31.284 mi) 2012–2019
Arbatsko-Pokrovskaya line Moscow Metro Russia Pyatnitskoye Shosse – Shchyolkovskaya 45.1 km (28.0 mi) 1938–2012
Sokolnicheskaya line Moscow Metro Russia Kommunarka – Bulvar Rokossovskogo 44.5 km (27.7 mi) 1935–2019
Lyublinsko-Dmitrovskaya line Moscow Metro Russia Zyablikovo – Fiztekh 44.3 km (27.5 mi) 1995–2023
Zamoskvoretskaya line Moscow Metro Russia Khovrino – Alma-Atinskaya 42.8 km (26.6 mi) 1938–2018
Line 8 Beijing Subway China Yuzhi Lu – Wufutang 42.6 km (26.5 mi) 2012–2021
Line 15 Shanghai Metro China Gucun Park – Zizhu Hi-tech Park 42.3 km (26.3 mi) 2021
Line 5 Chengdu Metro China Jiudaoyan – Huilong 42.3 km (26.3 mi) 2019
Tagansko-Krasnopresnenskaya line Moscow Metro Russia Planernaya – Kotelniki 42.2 km (26.2 mi) 1966–2015

Under construction

[edit]
See also: List of metro systems § Metro systems under construction

Only continuous tunnel sections should be included, at least 30 km (19 mi) long.

Name System Countries Stations Length Expected
completion
Line 15 Paris Métro France (circle route, all underground) 75 km (46.6 mi) 2026–2031
Cross Island Line Mass Rapid Transit (Singapore) Singapore (Linear route with branch section, all underground) 65.5 km (40.7 mi)[a] 2029–2031
L9 / L10 Barcelona Metro Spain Linear route 43.7 km (27.2 mi)[b] 2016[c]
Thomson–East Coast Line Mass Rapid Transit (Singapore) Singapore (Linear route, all underground excluding last 2 km [1.2 mi]) 42.8 km (26.6 mi) 2026–2028[d]
  Green line
 Baku Metro Azerbaijan (circle route, all underground) 41.8 km (26.0 mi) 2040
  1. ^ With stage 5, excluding potential extension from Punggol to Seletar Airport under planning
  2. ^ including branches
  3. ^ partially, central section unknown
  4. ^ extension to Tanah Merah expected beyond 2030

Road

[edit]
Main article: List of longest road tunnels
Name Location Length Year Tubes Road Notes
Lærdal Norway (Lærdal–Aurland) 24.51 km (15.2 mi) 2000 1 E16 Longest road tunnel in the world.
Yamate Tunnel Japan (Tokyo) 18.20 km (11.3 mi) 2007
2010
2015 		2 C2, Shuto Expressway
Zhongnanshan Tunnel China (Shaanxi) 18.04 km (11.2 mi) 2007 2 G65, Xi'an-Zhashui Expressway[19]
Jinpingshan Tunnel[20][21] China (Sichuan) 17.54 km (10.9 mi) 2011 2 between sites of Jinping-I and Jinping-II Hydropower Station 2 tubes, 17.540 km and 17.485 km
St. Gotthard Switzerland (Uri - Ticino) 16.918 km (10.5 mi) 1980 1 A2/E35 "World's longest tunnel" 1980 - 2000
Zigana Tunnel[22] Turkey (Maçka - Torul) 14.481 km (9.0 mi) 2023 2 D.885, E97
Ovit Tunnel Turkey (İkizdere - İspir) 14.346 km (8.9 mi) 2018[23] 2 D.925
Ryfylke tunnel Norway (Stavanger–Strand) 14.3 km (8.9 mi) 2019 2 13 The longest underwater road tunnel in the world
Arlberg Austria (Vorarlberg - Tyrol) 13.972 km (8.7 mi) 1978 1 S16/E60 "World's longest tunnel" 1979 - 1980
Xishan Tunnel China (Shanxi) 13.654 km (8.5 mi) 2012[24] 2 S56 Shanxi Taiyuan-Gujiao Expressway Left tube：13.654 m, right tube：13.570 m
New Erlangshan Tunnel[25] China (Sichuan) 13.433 km (8.3 mi) 2018 2 Ya'an-Kangding Expressway Left tube: 13.433 m, right tube: 13.381 m
Hongtiguan Tunnel China (Shanxi) 13.122 km (8.2 mi) 2013[26] 2 S76 Shanxi Changzhi-Pingshun Expressway Left tube: 13.122 m, right tube: 13.098 m[27]
Hsuehshan Taiwan 12.942 km (8.0 mi) 2006 2 5
Fréjus France - Italy 12.895 km (8.0 mi) 1980 2 E70 The longest road tunnel across an international border
KPE & MCE Expressway Tunnel Singapore 12.46 km (7.7 mi) 2008
2013 		1* Kallang–Paya Lebar Expressway (KPE) and Marina Coastal Expressway (MCE) Tunnel section of KPE (8.13 km) and MCE (4.33 km) are contiguous, hence classified as one tunnel.

*Dual carriageway 12 Lanes of traffic (maximum width: 70m) with each direction separated only by a full-height wall, thus considered to be one tube.
Maijishan Tunnel China (Gansu) 12.29 km (7.6 mi) 2009 2 G30, Baoji-Tianshui Expressway 2 tubes, 12.290 km and 12.286 km
Mt. Blanc France - Italy (Alps) 11.611 km (7.2 mi) 1965 1 E25 "World's longest tunnel" 1965 - 1979
Gudvangen Norway (Gudvangen–Flåm) 11.428 km (7.1 mi) 1991 1 E16
Yunshan Tunnel China (Shanxi) 11.408 km (7.1 mi) 2014 2 G2516 Dongyin-Luliang Expressway Left tube: 11.408 m, right tube: 11.377 m
Eysturoyartunnilin Faroe Islands 11.238 km (7.0 mi) 2020 1 Forked with roundabout and 3 entries. Segments 7.5 km (4.7 mi), 2.2 km (1.4 mi) and 1.7 km (1.1 mi) long.
Baojiashan Tunnel China (Shaanxi) 11.200 km (7.0 mi) 2009[28] 2 G65, Xi'an-Ankang Expressway Left tube: 11.200 m, right tube: 11.195 m
Folgefonna Norway (Odda–Eitrheim) 11.15 km (6.9 mi) 2001 1 49
Kan-etsu Tunnel Japan (Gunma - Niigata) 11.055 km (6.9 mi) 1985
1991 		2 Kan-Etsu Expressway Two tubes (the older 10.926 m)
Inje-Yangyang Tunnel [ko] South Korea (Gangwon Province) 10.962 km (6.85 mi) 2017 2 Seoul–Yangyang Expressway 10.965 km (Seoul bound) / 10.962 km (Yangyang bound)
Sandoyartunnilin Faroe Islands 10.900 km (6.8 mi) 2023[29] 1
Toven Tunnel[30] Norway (Leirfjord–Vefsn) 10.655 km (6.6 mi) 2014 1 78
Baotashan[31] China (Shanxi) 10.480 km (6.512 mi) 2012[32] 2 S66 Shanxi Hefen Expressway Left tube: 10.192 m, right tube: 10.480 m
Hida Japan (Gifu) 10.71 km (6.7 mi) 2008 1 Tokai-Hokuriku Expressway
Gran Sasso d'Italia Italy (Abruzzo) 10.176 km (6.3 mi) 1984
1995 		2 A24 Two tubes (the newer 10.173 m)
Jondal Tunnel Norway (Mauranger–Jondal) 10.05 km (6.2 mi) 2012 1 49
Nibashan Tunnel[a] China (Sichuan) 10.007 km (6.2 mi) 2012[33] 2 G5, Beijing-Kunming Expressway 2 tubes, 10.007 km and 9.962 km
Duplex A86 [fr] France (Rueil-Malmaison - Versailles) 10 km (6.2 mi) 2009/2011 1* A86 *the two two-lane directions are superimposed (hence duplex) in one tube
Many more tunnels exist that are shorter than 10 kilometres (6 mi)

Under construction

[edit]
Name Location Length Year Tubes Road Notes
Boknafjord Tunnel[34] Norway (Stavanger/Randaberg–Kvitsøy–Bokn) 26.7 km (16.6 mi)[35] 2031 2 European route E39 Mostly underwater. Will have a record depth of 390 m below sea level. A side tunnel (Kvitsøy Tunnel, 4 km) will connect Kvitsøy. Construction began on 4 January 2018.
Tianshan Shengli Tunnel China (Xinjiang) 22.1 km (13.7 mi)[36] 2025 2 Ürümqi–Ruoqiang Expressway
Fehmarn Belt fixed link Denmark / Germany 17.6 km

(11 mi)

2029 5 E47 Immersed tunnel combining road and rail. The tunnel segments consist of 5 tubes, 2 tubes for road, 1 for emergency and maintenance access and 2 for rail.
Bypass Stockholm[37] Sweden (Stockholm) 16.5 km (10.3 mi) 2030[38] 2 E4
Tokyo Gaikan Tunnel Japan (Tokyo) 16.2 km (10.1 mi) 2030 2 C3 Tokyo Gaikan Expressway
Zoji-la Tunnel India (Jammu Kashmir) 14.2 km (8.8 mi) 2026[39] 1 Srinagar-Kargil-Leh highway[40]
Micangshan Tunnel[citation needed] China (Sichuan) 13.833 km (8.6 mi) 2018[needs update] 2 Bazhong-Shaanxi Expressway Left tube: 13.833 m, right tube: 13.792 m[41]
Fjarðarheiðargöng Iceland 13.500 km (8.4 mi) 2032 1 Route 93 In planning. Actual construction starts in 2026.
Dongtianshan Tunnel China (Xinjiang) 13.240 km (8.2 mi) 2020[needs update] 1 National Highway G575
Huangtuliang Tunnel China (Sichuan) 13.010 km (8.1 mi) 2021 2 Mianyang-JiuzhaigouExpressway
NSC Expressway Tunnel Singapore 12.5 km (7.8 mi) 2026 1 North-South Corridor, Singapore Tunnel sections of NSC are (10.4 km), while sub-surface section is (2.1 km). Dual carriageway of 6 lanes with each direction separated only by a full-height wall, thus considered to be one tube.
Gaoloushan Tunnel China (Gansu) 12.248 km (7.6 mi) 2020[needs update] 2 Pingliang-Mianyang Expressway
Murovdag Tunnel Azerbaijan (Kalbajar) 11.713 km (7.3 mi) 2025 2 M2, European route E60
Yunshan Tunnel China (Shanxi) 11.408 km (7.1 mi) ?? 2 S66 Shanxi Hefen Expressway Left tube: 11.408 m, right tube: 11.377 m
Many more tunnels that are shorter than 10 kilometres (6 mi) are under construction

Water

[edit]
Name Location Length Year Notes
Delaware Aqueduct New York, United States 137 km (85.1 mi) 1945 Water supply. Drilled through solid rock.
Päijänne Water Tunnel Southern Finland, Finland 120 km (74.6 mi) 1982 Water supply (16 m2 cross section)
Dahuofang Water Tunnel Liaoning Province, China 85.3 km (53.0 mi) 2009 Water supply (8 m in diameter[42])
Orange–Fish River Tunnel South Africa 82.8 km (51.4 mi) 1975 Irrigation (22.5 m2 cross section)
Bolmen Water Tunnel Kronoberg/Scania, Sweden 82 km (51.0 mi) 1987 Water supply, 8 m2.
Želivka Water Tunnel[43] Central Bohemian Region, Czech Republic 51.1 km (31.8 mi) 1972 Water supply, 5 m2.
Arpa-Sevan Tunnel[44] Armenia
(at the time of construction USSR) 		48.3 km (30.0 mi) 1981 Water supply
#1 Tunnel, Yellow River Diversion to Shanxi North Line Shanxi, China 43.7 km (27.2 mi) 2011 Water supply
#7 Tunnel, Yellow River Diversion to Shanxi South Line Shanxi, China 43.5 km (27.0 mi) 2002 Water supply
High Island Water Tunnels Sai Kung Peninsula, New Territories, Hong Kong 40 km (24.9 mi) 1976 Water supply
Kárahnjúkar Hydropower Plant Eastern Region, Iceland 39.7 km (24.7 mi) 2003–2007 Hydroelectric. 7.2-7.6 meters in diameter. Part of a wider complex of tunnels that are 72 kilometers in length combined
Quabbin Aqueduct Massachusetts, United States 39.6 km (24.6 mi) 1905 Water supply
Evanger Hydropower Plant Evanger, Norway 34.4 km (21.4 mi) 1977 Hydroelectric. 30 m2
Talave Tunnel Albacete, Spain 31.8 km (19.8 mi) 1979 Part of the Tagus-Segura Water Transfer.
Evinos - Mornos Tunnel[45][46] Aetolia-Acarnania, Greece 29.4 km (18.3 mi) 1992–1995 Water supply
Palacio - Río blanco Tunnel[47] Bogotá, Colombia 28.4 km (17.6 mi) 1984 Water supply
Melamchi Water Tunnel Nepal, Melamchi to Kathmandu 27 km (16.8 mi) 2021[48] Water supply
Şanlıurfa Irrigation Tunnels Turkey 26.4 km (16.4 mi) 2005 Irrigation[49]
Gilgel Gibe II Power Station headrace tunnel Ethiopia 26 km (16.2 mi) 2005–2009 Hydroelectric. Tunnel partially collapsed, was repaired in 2010.[50][51]
Tai Lam Chung Tunnels Tai Lam Chung to Chai Wan Kok, New Territories, Hong Kong 24.45 km (15.19 mi) 1957–1974 Water supply
Grande Dixence headrace tunnel Switzerland 24 km (14.9 mi) 1951–2010 Hydroelectric. Total tunnel system 100 km.[52]
Kishanganga Hydroelectric Project India 23.2 km (14.4 mi)[53][54] 2017 Hydroelectric
Tala Hydroelectricity Project headrace tunnel Bhutan 22 km (13.7 mi) 2004[55] Hydroelectric. 6.8 meters in diameter.
Vorotan-Arpa Tunnel Armenia 21.7 km (13.5 mi) 2004 Water supply.
Plover Cove Stage 1 Tunnels Plover Cove, New Territories, Hong Kong 20.2 km (12.6 mi) 1965–1971 Water supply
Olmos Transandino Project Peru 20 km (12.4 mi) 2011[56] Water supply
Mantaro Hydroelectricity Project [es] Peru 19.8 km (12.3 mi) 1973[57] Hydroelectric
Tatev Hydroelectric Power Station Water Tunnel Armenia
(at the time of construction Soviet Union) 		18.4 km (11.4 mi) 1970 Hydroelectric
Plover Cove Stage 2 Tunnels Plover Cove, New Territories, Hong Kong 18.2 km (11.3 mi) 1967 Water supply
Suruç Water Tunnel Suruç, Şanlıurfa Province, Turkey 17.2 km (10.7 mi) 2014[58] Irrigation
Mavi Tünel (Blue Tunnel)[59] Konya, Turkey 17 km (10.6 mi) 2012 Irrigation
Sri Ranganayaka Sagar - Kondapochamma Sagar Tunnel[60] Telangana, India 16.18 km (10.1 mi)[61] 2020 Irrigation. Part of Link-IV, Package-12 of Kaleshwaram Lift Irrigation Project.
Inguri Hydroelectric Power Station Water Tunnel Georgia
(at the time of construction Soviet Union) 		15.3 km (9.5 mi) 1978 Hydroelectric
Many more tunnels exist that are shorter than 15 kilometres (9 mi)

Under construction

[edit]
Name Location Length Year Notes
Ramappa to Dharmasagar Tunnel[62] Telangana, India 49.06 km (30.5 mi) 2022[needs update] Irrigation. Part of J. Chokka Rao Devadula lift irrigation sceheme[63][64]
Srisailam Left Bank Canal Tunnel - I[65] Srisailam Dam, India 43.931 km (27.3 mi) 2021[needs update][66][67] Irrigation
Mae Taeng–Mae Ngat Tunnel[68] Chiang Mai, Thailand 25.624 km (15.9 mi) 2021[needs update] Irrigation. 4 m in diameter
Mae Ngat–Mae Kuang Tunnel[68] Chiang Mai, Thailand 22.975 km (14.3 mi) 2021[needs update] Irrigation. 4.2 m in diameter
Poola Subbaiah Veligonda Project Tunnel - II[69][64] Andhra Pradesh, India 18.83 km (11.7 mi) 2021[needs update] Irrigation
Poola Subbaiah Veligonda Project Tunnel - I[69][64] Andhra Pradesh, India 18.82 km (11.7 mi) 2020[needs update][70] Irrigation
Many more tunnels that are shorter than 15 kilometres (9 mi) are under construction

Note: There are buried oil and gas pipelines, up to several thousand kilometers long. See also:

Bicycle and pedestrian

[edit]

Most of the tunnels listed were built for other purposes, and have not been redesigned. The Fyllingsdalentunnelen is one example of a tunnel built to purpose from the start.

The tunnels listed here can be either be pure cycling tunnels and/or pedestrian tunnels with separate tubes, or shared-use tunnels (i.e. having a shared lane, or a bike lane and footpath without a non-crossable physical separation).

Name Type
(pedestrian / cyclist) 		Location Length Trail
Snoqualmie Tunnel Former railway tunnel,
Gravel,
No lighting 		United States, King and Kittitas Counties, Washington 3,625 m (11,893 ft)[71] Palouse to Cascades State Park Trail
Fyllingsdalstunnelen Purpose-built,
Shared-use path,
Two bikelanes,
Slightly elevated sidewalk,
Asphalt,
Good lighting 		Norway, Bergen 2,900 m (9,514 ft)[72][73] Fyllingsdalen to Bergen City Center
St. Paul Pass Tunnel Former railway tunnel,
Shared-use path,[74]
Gravel,
No lighting 		United States, Montana and Idaho 2,736 m (8,976 ft) The Route of the Hiawatha
Slavošovský tunel[75] Unfinished railway tunnel,sv
Gravel,
No lighting 		Slovakia, Slavošovce, Košický kraj 2,400 m (7,874 ft) Slavošovce to Revúca blue Trail number 2589
Old Caoling Tunnel Former railway tunnel,
Shared-use path 		Taiwan, Yilan County and New Taipei City 2,167 m (7,110 ft) Abandoned single-track railway tunnel
Kerem Tunnel Utility tunnel,
Asphalt,
Lighting,
Cycling only 		Israel, Jerusalem 2,100 m (6,890 ft)[76] Jerusalem Bicycle Trails
Sideling Hill Tunnel Former railway tunnel,
Former car tunnel,
Asphalt,
No lighting[77] 		United States, Fulton County, Pennsylvania 2,067 m (6,781 ft) Pike 2 Bike Trail
Kinuura Tunnel Car tunnel and separate Pedestrian tunnel[78] Japan, Aichi Prefecture 1,700 m (5,577 ft)
Combe Down Tunnel Former railway tunnel,
Asphalt,
Lighting[79] 		United Kingdom, Bath, England 1,672 m (5,486 ft) Two Tunnels Greenway
Tunnel du Bois Clair Former railway tunnel,
Asphalt,
Lighting,
Summer open only[80] 		France, Sologny 1,600 m (5,249 ft) Voie Verte de Bourgogne du Sud (Chalon-sur-Saône to Mâcon)
Niwärch Stollen Irrigation tunnel,
Gravel,
No lighting[81] 		Switzerland, Ausserberg, Valais 1,379 m (4,524 ft) Niwärch Bisse
Claudius Crozet Blue Ridge Tunnel Former railway tunnel,
Asphalt,
No lighting[82] 		United States, Nelson/Augusta County, Virginia 1,291 m (4,237 ft) Claudius Crozet Blue Ridge Tunnel Trail
Norwalk Tunnel Former railway tunnel,
Dirt road,[83] No lighting,[84] Only walking recommended[84] 		United States, Elroy, Sparta, Wisconsin 1,161 m (3,809 ft) Elroy-Sparta State Trail
Wassertunnel Gredetschtal Waterline tunnel,
Gravel,
No lighting 		Switzerland, Mund 1,120 m (3,675 ft) Wyssa Suonen Trail
Tidenham Tunnel Former railway tunnel,
Shared-use path,[85]
Lighting,
Asphalt,
Summer open only[86] 		United Kingdom, Tidenham and Tintern 1,086 m (3,563 ft) Wye Valley Greenway
Karangahake Tunnel Former railway tunnel,
Shared-use path,
Asphalt pavement,
Lighting[87] 		New Zealand, Waihi 1,086 m (3,563 ft) Hauraki Rail Trail
Rays Hill Tunnel Former railway tunnel,
Former car tunnel,
Asphalt,
No lighting[88] 		United States, Bedford and Fulton Counties, Pennsylvania 1,076 m (3,530 ft) Pike 2 Bike Trail
Maastunnel Purpose built,
Separate cyclist tube,
Separate pedestrian tube, Concrete floor,[89]
Good lighting 		Netherlands, Rotterdam 1,070 m (3,510 ft)
Bonassola Pastorelli Tunnel Former coastal railway tunnel,
Asphalt,
Two bike lanes,
One walking lane 		Italy, Bonassola 1,036 m (3,399 ft) Pista Ciclopedonale Maremonti
Kennerdell Tunnel Former railway tunnel,
Shared use,
Asphalt,[90]
No lighting 		United States, Venango County, Pennsylvania 1,021 m (3,350 ft) Erie to Pittsburgh Trail
Big Savage Tunnel Former railway tunnel,
Asphalt,
Lighting,
Summer open only[91] 		United States, Somerset County, Pennsylvania 1,004 m (3,294 ft) Great Allegheny Passage

Sewerage

[edit]

Power

[edit]

Gas

[edit]

Bored

[edit]

Cut-and-cover

[edit]

Mined

[edit]
  • Caltrain San Francisco Downtown extension[92]
  • City Rail Link[93]
  • Crossrail (Bond Street station)[94][95]
  • (Part of) Küssnacht Southern Bypass[96]
  • (Part of) Wanchai Bypass[97]

Drill and blast

[edit]

Immersed tube

[edit]

Double-decker or multi-level

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See also

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List of long tunnels by type

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A list of long tunnels by type compiles the world's most extensive underground or underwater passages, categorized primarily by their function—such as vehicular (road), railway, water supply, subway/metro, and utility—typically including those exceeding 10 kilometers in length to highlight engineering feats that overcome geographical barriers like mountains, seas, and urban constraints. These structures, often built using advanced tunneling methods like tunnel boring machines, serve critical roles in transportation, resource distribution, and infrastructure resilience, with lengths measured as the continuous bored or constructed path excluding branches or shafts. Among the major categories, road tunnels facilitate highway traffic through impassable terrain; the longest operational example is Norway's at 24.51 kilometers, connecting the fjord regions of Aurland and since 2000 to reduce travel times and enhance safety by avoiding treacherous mountain roads. Railway tunnels enable high-speed freight and passenger rail across continents; Switzerland's holds the record at 57.09 kilometers, operational since 2016, revolutionizing Alpine transit by allowing trains to pass under the Gotthard Massif at speeds up to 250 km/h. Water supply tunnels, often aqueducts, transport vast volumes of water over long distances; the Delaware Aqueduct in New York, , is the longest at 137 kilometers, delivering about half of New York City's drinking water from the since its completion in 1945. Other types, such as subway systems and diversions, address and environmental needs, with examples like Japan's extensive metro networks pushing boundaries in crowded megacities. These lists evolve with ongoing projects, such as China's numerous megatunnels and Europe's undersea connections, underscoring global advancements in .

Rail Tunnels

Operational

Operational rail tunnels are subterranean passages designed for railway transport, including freight and passenger services, with a focus on those exceeding 10 kilometers in length to highlight significant engineering feats for overcoming geographical barriers like mountains and seas. These tunnels often feature double-track designs, advanced ventilation, signaling systems, and high-speed capabilities up to 250 km/h or more, enhancing connectivity and efficiency in global rail networks. Built using methods like tunnel boring machines, they reduce travel times and environmental impact compared to surface routes. As of November 2025, the longest rail tunnels are predominantly in and , serving high-speed and lines. The in , at 57.1 kilometers, is the world's longest operational rail tunnel, opened in 2016 as part of the New Railway Link through the (NRLA). It passes under the Gotthard Massif, allowing trains to travel at speeds up to 250 km/h, significantly reducing transit times between northern and while minimizing energy use and emissions. The twin-tube design includes cross-passages for safety and maintenance access. Another key example is Japan's Seikan Tunnel, measuring 53.9 kilometers and operational since 1988, connecting and under the . As the longest undersea rail tunnel in , it supports bullet trains and freight, with features like earthquake-resistant construction and water-tight seals to handle seismic activity and marine pressures. The Channel Tunnel between and the , at 50.5 kilometers, has been operational since 1994, linking and Coquelles under the . This immersed tube and bored tunnel hybrid carries passenger services and freight shuttles, with safety systems including evacuation galleries and fire suppression.
Tunnel NameLength (km)LocationOpening YearKey Features
Gotthard Base Tunnel57.12016Twin-tube, 250 km/h speeds, part
Seikan Tunnel53.9Japan1988Undersea, compatible
Channel Tunnel50.5France/UK1994Undersea, and freight
These tunnels exemplify advancements in rail infrastructure, supporting across continents.

Under Construction

Rail tunnels under construction or in advanced planning stages are defined here as railway infrastructure projects exceeding 10 km in planned , dedicated to or freight rail. These initiatives typically include details on name, , location, start year, expected completion date, and engineering features such as base-level alignments for high speeds or seismic reinforcements. As of November 2025, major projects focus on trans-Alpine and Asian high-speed networks, addressing capacity and connectivity challenges. A prominent example is the between and , planned at 55 kilometers (part of a 64 km continuous system), connecting and Fortezza under the . Construction began in 2008, with main tunneling advancing since 2016 and expected completion in 2032. The project features a flat gradient of 4-7% for 250 km/h operations, twin single-track tubes, and environmental measures like low-emission boring, aiming to boost freight capacity between northern and . Recent breakthroughs in exploratory tunnels occurred in 2025. In and , the (also known as Lyon-Turin Base Tunnel) measures 57.5 kilometers, linking and through the . Drilling started in 2011, with full completion targeted for 2032 as part of the Lyon-Turin Ferroviaire line. It includes base-level routing to avoid steep inclines, supporting mixed freight and passenger traffic at up to 250 km/h, with safety features like pressurized ventilation and fire detection systems. China's Yigong Tunnel, at 42.4 kilometers, is under construction on the - Railway in , with work ongoing since 2021 and completion expected by 2030. This high-altitude navigates seismic zones with reinforced linings and systems, enabling rail access to remote areas at elevations over 4,000 meters. These projects highlight global efforts to expand rail networks, though delays due to geological challenges and funding are common.

Road Tunnels

Operational

Operational road tunnels are subterranean or underwater passages designed for vehicular traffic, including cars, trucks, and buses, typically those exceeding 10 kilometers in length to emphasize major infrastructure projects that bypass mountains, fjords, or urban congestion. These tunnels often feature dual tubes for bidirectional flow, advanced ventilation to manage vehicle emissions, emergency exits every 500 meters, and lighting systems to ensure safety during long drives. Constructed using methods like drill-and-blast or tunnel boring machines, they reduce travel times and improve road safety by avoiding hazardous surface routes. As of November 2025, the longest road tunnel remains Norway's Lærdal Tunnel at 24.51 km, operational since 2000. The connects Lærdalsøyri and Aurlandsvangen in county, , spanning the region to shorten the E16 route across the mountains. Opened on November 27, 2000, after five years of construction costing about 1.08 billion , it includes four large cavern halls every 6 km to relieve driver monotony and reduce fatigue, with blue LED lighting simulating daylight. The single-tube tunnel accommodates two lanes at 80 km/h , handling up to 1,000 vehicles per hour, and features a constant 11.5°C temperature with natural ventilation supplemented by axial fans. Another significant example is the in , , measuring 18.20 km and forming part of the Central Circular Expressway (C2). Completed in stages with full operation by 2015, this double-deck tunnel (upper for outbound, lower for inbound traffic) navigates under urban areas, reducing surface congestion in one of the world's densest cities. It includes noise barriers, , and real-time traffic monitoring, with construction involving cut-and-cover and shield tunneling methods to minimize disruption.
Tunnel NameLength (km)LocationOpening YearKey Features
Lærdal Tunnel24.512000Cavern halls for breaks, LED lighting, natural ventilation
Yamate Tunnel18.202015Double-deck design, urban congestion relief, fire suppression
Zhongnanshan Tunnel18.042007Dual tubes, mountain bypass on G65 expressway
These tunnels highlight global advancements in safety and efficiency, with many in mountainous or coastal regions like and dominating the lists due to terrain challenges.

Under Construction

Road tunnels under construction or in advanced planning are defined here as vehicular infrastructure projects exceeding 10 km in planned length, dedicated to automobile and truck traffic. These projects often detail name, length, location, construction start year, expected completion date, and innovations such as subsea design or seismic resilience to support regional connectivity and economic growth. As of November 2025, major developments focus on undersea and mountain crossings in Europe and Asia, addressing climate-resilient transport needs. A leading project is the in , planned at 26.7 km to connect Randaberg near to Arsvågen in Finnøy across the Boknafjord. Construction began in 2023, with tunneling underway using submerged tube and drill-and-blast methods; expected completion is 2033 at a cost of approximately 28 billion NOK. As the world's longest and deepest subsea road tunnel (reaching 392 m below ), it will feature twin tubes for the E39 coastal highway, reducing ferry-dependent travel time from 90 minutes to 20 minutes while incorporating advanced safety systems like radar-based collision avoidance. In , the Tianshan Shengli Tunnel measures 22.13 km through the Tianshan Mountains in , linking Urumqi to Yuli on the planned Urumqi-Yuli Expressway. Tunneling was completed in December 2024, with construction starting in 2020; full opening is targeted for late 2025. This dual-tube tunnel will shorten transit across the middle Tianshan section from seven hours to about 20 minutes, using tunnel boring machines to navigate high-altitude and seismic zones, enhancing connectivity to . The Fehmarn Belt Tunnel, a combined road-rail project at 18 km, connects Rødbyhavn in to Puttgarden in across the . Construction started in 2021, with the first elements immersed in 2025; completion is expected in 2029. It will include four road lanes and two rail tracks in a 40 m deep trench, cutting Hamburg-Copenhagen travel by an hour and featuring airtight seals for flood protection and charging stations. These initiatives demonstrate commitments to sustainable transport, such as electric-ready infrastructure and reduced emissions from shorter routes, though they face challenges like environmental approvals and high costs compared to surface alternatives.

Rapid Transit Tunnels

Operational

Rapid transit tunnels are underground passages constructed for urban rail systems, including subways and metros, to provide high-capacity passenger transport in densely populated areas. These tunnels often exceed 50 kilometers in continuous length for major lines, utilizing methods like tunnel boring machines to navigate urban obstacles, with features such as automated signaling, platform screen doors, and high-speed rail compatibility to enhance efficiency and safety. Globally, China dominates with extensive networks, where long tunnel sections facilitate connectivity across expansive cities while minimizing surface disruption. The longest operational tunnel is the main branch of Line 3 in , , measuring 67.3 kilometers and fully underground since its completion in phases from 2005 to 2010. This north-south line connects key districts including the airport and serves over 1.7 million passengers daily, featuring 30 stations and advanced ventilation systems to maintain air quality in its continuous bored path. Another significant example is Line 10, a 57.1-kilometer circular loop entirely underground, operational since 2008, passing through central districts like Chaoyang and Haidian. It supports high-frequency service with 24 stations, incorporating energy-efficient lighting and , and handles millions of commuters by integrating with other lines for seamless transfers. Chengdu Metro Line 6, at 68.2 kilometers, ranks among the longest, opened in 2020 as China's longest single-phase underground line, connecting Wangcong Temple to Lanjiagou with 56 stations. Designed for suburban , it includes express and local services, with robust to withstand seismic activity in the region.
Tunnel NameLength (km)LocationOpening YearKey Features
Guangzhou Metro Line 3 (main branch)67.3, 2005 (phased to 2010)Fully underground, 30 stations, high passenger capacity
Beijing Subway Line 1057.1, 2008Circular loop, 24 stations, automated signaling
Chengdu Metro Line 668.2, 202056 stations, seismic-resistant design, express service
These tunnels highlight advancements in urban mobility, with ongoing maintenance ensuring operational reliability amid increasing demand.

Under Construction

tunnels under construction focus on expanding urban networks with long continuous sections, often exceeding 20 kilometers, to address growing transit needs. These projects incorporate sustainable features like electric propulsion and green construction materials, with details on expected lengths and completion dates as of November 2025. continues to lead in scale, with several megaprojects advancing. A notable project is the Airport Link extension, featuring a 60.5-kilometer section under construction since 2023, expected to complete in late 2025. This immersed and bored will connect Airport to the city center at speeds up to 450 km/h, enhancing high-speed urban transit with advanced and noise reduction. In , the Line 3 northern extension adds 9.6 kilometers of underground , started in 2021 and set for completion in 2025, integrating with the existing long to further boost airport connectivity using tunnel boring machines for minimal disruption. Another initiative is the Metro's multiple lines, including a 40+ kilometer tunnel section for Line 1, under construction since 2014 with phased openings targeted for 2025, featuring driverless trains and climate-controlled environments suited to desert conditions. These developments underscore global efforts to scale infrastructure, though challenges like funding and geological complexities persist. As of November 2025, over 1,300 kilometers of new metro lines opened worldwide in 2024, primarily in .

Waterway Tunnels

Operational

Waterway tunnels, also known as navigation or canal tunnels, are subterranean passages designed for vessels such as boats and barges to traverse obstacles like hills or mountains, typically those exceeding 1 kilometer in length to emphasize engineering achievements in maritime infrastructure. These tunnels often feature towpaths (historically for horse-drawn boats) or electric tugs for propulsion due to ventilation limitations prohibiting engine use inside. Globally, operational examples are rare and mostly historical, concentrated in , where they connect inland waterways for freight and leisure boating while preserving scenic routes. The longest operational waterway tunnel is the Riqueval Tunnel (also called the Grand Souterrain) on the in , measuring 5.67 kilometers and completed in 1810 under Napoleon's direction. Located near Bellicourt in the department, it links the Somme and rivers, facilitating traffic with a width of 17 meters and height of 9.4 meters. Propulsion is provided by electric towboats due to the absence of ventilation, ensuring safe passage for vessels up to 300 tons; it remains a vital link in France's network, handling commercial and recreational . Another significant example is the Standedge Tunnel on the in , , at 5.21 kilometers, restored and reopened for navigation in 2001 after closures. Stretching under the between Marsden and Diggle, it is the longest, deepest (194 meters below ground), and highest (198 meters above ) canal tunnel in Britain. Narrowboats are towed through by electric tugs at 3 km/h, with features including LED lighting and real-time monitoring for safety; it supports leisure boating and tourism, including guided paddling trips.
Tunnel NameLength (km)LocationOpening YearKey Features
Riqueval Tunnel5.67, 1810Electric towboats, 17m width, no engine use
Standedge Tunnel5.21/, 2001 (restored)Electric tugs, LED lighting, deepest/highest in UK
These tunnels highlight historical innovations in inclined planes and towing systems, though modern usage focuses on sustainable inland transport amid declining commercial freight.

Under Construction

Waterway tunnels under construction are navigation projects exceeding 1 km, aimed at improving maritime safety and efficiency, often incorporating modern features like automated controls and environmental protections. As of November 2025, such projects are limited, with the focus on coastal ship tunnels to avoid hazardous open seas. The most prominent is the Stad Ship Tunnel in Norway, planned at 1.7 kilometers to bypass the treacherous Stadhavet Sea around the Stad Peninsula. Approved in 2017, construction is set to commence in late 2025, with completion expected by 2029-2031 at a cost of approximately 2.2 billion NOK (about $200 million USD). Designed for vessels up to 1600 tons (including cargo ships and ferries), it will feature a 37-meter height, 36-meter width, and rock-shedding systems for safety, powered by renewable energy; this will reduce weather-related delays and emissions by shortening routes. No other major waterway tunnels exceeding 1 km are currently under construction as of November 2025, though feasibility studies continue in regions like for inland expansions. These initiatives underscore efforts to enhance resilient shipping corridors in response to climate-driven increases.

Bicycle and Pedestrian Tunnels

Operational

Operational pedestrian and bicycle tunnels are subterranean passages designed exclusively for non-motorized , accommodating walkers, cyclists, and sometimes users, with a focus on those exceeding 1 kilometer in length to highlight significant feats for urban or recreational connectivity. These tunnels prioritize through features like continuous lighting, ventilation systems, and call points, often integrating multi-use paths to promote sustainable mobility in areas with challenging such as mountains or rivers. Due to preferences for above-ground routes and cost considerations, long examples remain limited globally, with most operational tunnels being repurposed from former rail lines or purpose-built in recent decades to alleviate . A prominent example is the Fyllingsdalstunnelen in , , which at 2.9 kilometers holds the distinction as the world's longest purpose-built tunnel for bicycles and pedestrians, opened in April 2023 to connect residential areas with the city center through Løvstakken Mountain. This tunnel features dynamic LED lighting that changes colors to guide users, artistic installations including a , resting benches every 500 meters, and a constant temperature of 7°C year-round, enhancing user comfort and encouraging daily while reducing . Ventilation ensures good air quality, and its design includes separate lanes for cyclists and pedestrians with a maximum of 20 km/h for . Another notable operational tunnel is the Snoqualmie Tunnel in Washington State, USA, measuring 3.7 kilometers and repurposed from a 1929 railroad alignment into a multi-use path for hiking and biking as part of the Iron Horse State Park Trail since 2001. Lacking artificial lighting, it requires visitors to use headlamps due to complete darkness throughout its length, maintaining a cool 4°C interior that demands warm clothing; accessibility includes a gravel surface suitable for hybrid bikes but challenging for road bikes. Safety innovations here emphasize natural ventilation and trailhead education on hypothermia risks, making it a popular recreational route despite seasonal closures from November to May for bat hibernation.
Tunnel NameLength (km)LocationOpening Year (for Pedestrian/Bike Use)Key Accessibility Features
Fyllingsdalstunnelen2.9, 2023LED color lighting, art installations, benches, ventilation
Snoqualmie Tunnel3.7Washington, 2001 (repurposed) required, natural ventilation, gravel path
These tunnels exemplify innovations in air quality monitoring and lighting to mitigate urban barriers, though many parallel existing tunnels for shared efficiency.

Under Construction

Bicycle and tunnels under construction or in advanced planning stages are defined here as non-motorized projects exceeding 1 km in planned length, dedicated primarily to and walking. These initiatives typically include details on name, length, location, start year, expected completion date, and features such as energy-efficient , natural ventilation, or resilient materials to support urban mobility and environmental goals. As of November 2025, such projects remain sparse, with no major long tunnels exceeding 1 km under construction or announced since 2023, highlighting the challenges of funding and engineering for exclusively non-motorized . These examples underscore urban connectivity objectives, such as reducing reliance on motorized and improving in densely populated areas, though the overall pipeline for such tunnels remains limited compared to vehicular .

Utility Tunnels

Sewerage Tunnels

Sewerage tunnels serve as for transporting and in densely populated urban areas, reducing overflows into rivers and improving and . These structures are typically bored or mined deep underground to avoid surface disruption, with inclusion in this list limited to those exceeding 10 km in length dedicated primarily to sewage conveyance. Key attributes include their integration with treatment plants for processing, capacities measured in cubic meters per second or volume, and features like earthquake resistance in seismically active regions. Representative examples illustrate advancements in handling combined sewer overflows (CSOs) and integration. One prominent example is the Túnel Emisor Oriente in , , a 62 km long wastewater tunnel completed in 2019 that conveys from the city's eastern zone to the Ayala treatment plant, with a capacity of up to 150 m³/s to manage and reduce in local waterways. Another significant project is the Milwaukee Metropolitan Sewerage District Deep Tunnel in , Wisconsin, United States, spanning 31.2 km and operational since 1994, designed to store and divert CSOs with a capacity of approximately 1.97 billion liters before pumping to the Jones Island wastewater treatment facility. In , the Metropolitan Sewerage Tunnels form a network totaling around 70 km of deep underground conduits constructed from the 1960s through the , featuring earthquake-resistant designs to withstand seismic events while conveying to multiple treatment plants; these tunnels also support dual-use flood control by managing excess during heavy rains. Similarly, India's Master Plan Sewer Tunnels include network segments exceeding 50 km laid in the as part of the city's trunk system, which integrates with plants like those at Coronation Pillar and to handle from over 20 million residents. The DC Water Clean Rivers Project in Washington, D.C., , encompasses approximately 25 km of tunnels under since 2010, with major components completed by 2023 and ongoing work expected until 2030, with a system capacity reducing overflows by up to 96% annually and directing flows to the Blue Plains Advanced Wastewater Treatment Plant for processing. These projects highlight the of , where long tunnels not only transport waste but also incorporate resilient features like dual-purpose functionality, though comprehensive updates on global systems remain limited post-2023 due to ongoing constructions and proprietary data.

Power Tunnels

Power tunnels, also known as headrace or tunnels, are underground conduits designed primarily for hydroelectric power generation or high-voltage electrical transmission, facilitating the transport of under to turbines or carrying power cables through challenging terrains. These structures are typically included in lists of long tunnels if they exceed 20 km in length, emphasizing their role in harnessing remote for production while navigating complex geological conditions such as high , fault zones, and ingress. Unlike utility tunnels for gas or , power tunnels prioritize hydraulic , structural integrity under extreme pressures, and electrical insulation where applicable, often requiring advanced excavation techniques like tunnel boring machines (TBMs) to mitigate risks like rockbursts and deformations. The Neelum–Jhelum Hydropower Tunnel in stands as one of the longest headrace tunnels globally, measuring 48.2 km and diverting water from the to the for power generation. Completed and operational since 2013, it supports a 969 MW installed capacity across four turbines, with an annual energy output of approximately 5.15 billion kWh, contributing significantly to Pakistan's needs. Construction faced substantial geological challenges in the Himalayan region, including shear zones that triggered rockbursts and tunnel collapses, necessitating remedial measures like rock bolting and concrete lining to address instability in fractured rock masses. In , the Jinping II Hydropower Station features four parallel headrace tunnels, each approximately 16.7 km long, which, while slightly under the 20 km threshold, exemplify ultra-high-pressure systems with a static water head exceeding 300 m and depths up to 2,500 m. Operational since 2014 (with initial units in 2012), the project delivers a total station capacity of 4,800 MW, generating over 15 billion kWh annually through efficient water diversion across the Yalong River. The tunnels encountered severe geological hurdles, including high in-situ stresses causing frequent rockbursts and water inrushes from aquifers, managed via TBM excavation, pre-grouting, and real-time monitoring to ensure stability in and formations. Another notable example is India's Nathpa Jhakri Project, with a 27.4 km headrace tunnel connecting the River's Nathpa intake to the underground powerhouse. Commissioned in 2004, it powers a 1,500 MW facility, producing around 6.5 billion kWh yearly and representing a milestone in Himalayan tunneling. Geological challenges included navigating weak sedimentary rocks and high , addressed through drill-and-blast methods supplemented by systematic support systems to prevent deformations.
Tunnel NameLength (km)LocationOpening YearCapacity (MW)Key Geological Challenge
Neelum–Jhelum Hydropower Tunnel48.2 (Azad )2013969Shear zones causing rockbursts and collapses
Jinping II Headrace Tunnels (x4)16.7 each ()20144,800 (station)High leading to rockbursts and water inrush
Nathpa Jhakri Headrace Tunnel27.4 ()20041,500Weak sedimentary layers and seismic activity
These examples highlight the engineering feats in power tunnel construction, though comprehensive global lists remain incomplete, particularly for recent Asian projects post-2023, due to ongoing developments in regions like the and .

Gas Tunnels

Gas tunnels are subterranean passages designed specifically to house high-pressure pipelines, facilitating the safe transport of flammable hydrocarbons over long distances while minimizing surface disruption and environmental impact. These tunnels typically exceed 15 km in length and incorporate advanced to withstand geological challenges, such as mountainous terrain or urban areas, with features like reinforced linings and ventilation systems to manage pressure and prevent leaks. Unlike surface pipelines, gas tunnels provide enhanced protection against external threats, including or , and often include integrated safety technologies for real-time monitoring. However, long gas tunnels exceeding 15 km are rare, with most examples being shorter river crossings or landfalls. These projects highlight the evolution of gas infrastructure, where tunnels incorporate resilient features, though comprehensive updates on global systems remain limited post-2023 due to ongoing constructions and proprietary data. Notable shorter examples include the Humber Gas Tunnel in the , a 4.96 km bored tunnel completed in 2020 that crosses under the River Humber, operating at high pressure with advanced insertion techniques for installation.

Tunnels by Construction Method

Bored Tunnels

Bored tunnels are excavated using tunnel boring machines (TBMs), cylindrical machines equipped with rotating cutterheads that grind through rock or while simultaneously installing lining segments behind the advancing face. This mechanized method enables continuous excavation over long distances, minimizing surface disruption and achieving advance rates far exceeding traditional drill-and-blast techniques, often up to 50 meters per day in favorable conditions. TBMs are ideal for deep, stable geological formations, such as those encountered in alpine rail projects, and have been instrumental in constructing some of the world's longest continuous tunnels since the 1970s. Inclusion in this list requires tunnels exceeding 10 km in length, fully excavated by TBM, with details on key operational examples across rail and uses. The following table highlights representative TBM-bored tunnels over 10 km, focusing on their scale, construction parameters, and notable achievements. These examples demonstrate TBM versatility in environments, with machines typically featuring high- drives and systems to handle pressures up to 2,000 meters.
Tunnel NameLength (km)LocationBoring Diameter (m)Excavation PeriodMachine SpecsUnique Facts
Gotthard Base Tunnel57.1 (, Erstfeld to Bodio)9.43–9.582003–2011Gripper TBMs; cutterhead power 3,500 kW; 8,526 kNm; up to 27,000 kNWorld's longest railway ; record advance of 56 m in 24 hours achieved in 2009; excavated 85 km total with four TBMs in hard and .
Channel Tunnel (running tunnels)38.3 (each, total system 50.5)– ( seabed)8.361988–1991Earth pressure balance TBMs; 13-inch disc cutters; 65,871 kN; 5,727 kNmLongest undersea rail link; six TBMs bored twin running tunnels in chalk marl, meeting precisely at midpoint after 11 km drives each.
Guadarrama Tunnel28.4 (, Madrid to Valladolid)9.5 (excavated)2002–2007Double-shield TBMs; diameter 9.5 m; capacity for 900 m Longest tunnel in ; four TBMs navigated and , with cross-passages every 250 m for safety.
West Qinling Tunnel28.2 (total, bored sections 16.6 each) ( Province, Lanzhou–Chongqing Railway)10.22011–2014 TBMs; 17-inch cutters; designed for squeezing groundSecond-longest railway tunnel in ; twin parallel bores in mountainous terrain, linking major economic corridors.
Qinling Tunnel18.0 ( Province, Xi'an–Ankang Railway)8.81995–2005Double-shield TBMs; imported Wirth machines for Early large-scale TBM use in ; excavated through fractured , advancing 5,621 m in 18 months despite challenges.
These tunnels exemplify TBM efficiency in rail applications, where consistent and minimal overbreak reduce lining costs and enable high-speed operations up to 250 km/h. For instance, the Gotthard Base Tunnel's allowed grip on tunnel walls for in variable rock, achieving over 70 m/day averages in optimal sections despite faults. Cross-use examples include potential adaptations for road or utility bores, though rail dominates long TBM projects due to alignment demands.

Cut-and-cover Tunnels

The cut-and-cover technique constructs tunnels by excavating an open from the surface, erecting structural walls and roof within the excavation, and then backfilling over the structure to reinstate the ground level. This method is favored for relatively shallow alignments in soft ground or urban settings, where depths typically range from 5 to 20 meters, allowing for straightforward access and without specialized underground equipment. For long tunnels exceeding 5 km, cut-and-cover is often applied in segmented urban corridors, such as metro lines or depressed highways, though it is less prevalent for continuous very long bores due to prolonged surface disruption and higher costs in densely built areas. Inclusion criteria for long cut-and-cover tunnels emphasize total lengths over 5 km, prioritizing urban infrastructure projects where the method's supports integration with surface features. Key details include the tunnel's name, overall length, location, construction period, typical depth, and backfill approaches, such as , decking, or temporary bridging to minimize impacts during building. Backfill methods often involve layered granular materials for stability, followed by membranes and surface restoration to match pre-construction conditions. Representative examples illustrate the application of cut-and-cover for extended urban tunnels, particularly in systems. The Moscow Metro's Koltsevaya (Ring) Line, spanning 19.4 km in , , was constructed from 1937 to 1954 at depths of 8-12 meters using open-trench excavation and lining, with backfill consisting of compacted earth and pavement reinstatement to support ongoing urban development. The Taipei MRT Bannan (Blue) Line features about 8 km of urban cut-and-cover tunnels built in the 1990s, at depths around 10-15 meters, with backfill using slurry walls for control and asphalt restoration for street-level recovery.
Tunnel NameLength (km)LocationConstruction YearsTypical Depth (m)Backfill Methods
Moscow Metro Koltsevaya Line19.4, 1937-19548-12Compacted earth layers, concrete slabs, pavement restoration
Taipei MRT Bannan Line (urban sections)~8, 1990s10-15Slurry wall stabilization, soil compaction, asphalt overlay
Canada Line Underground Section6.6, 2005-200910-20Shotcrete shoring, reinforced backfill, surface reinstatement
These projects highlight innovations in mitigating traffic disruption, such as phased excavation and protective canopies in urban settings, which allowed partial surface use during building despite the method's inherent urban interference. Cut-and-cover remains a staple for urban where shallow geology permits, though its use for tunnels beyond 10-20 km is rare owing to escalating surface impacts and alternatives like bored methods.

Mined Tunnels

Mined tunnels are underground passages excavated primarily through manual or semi-mechanized labor, utilizing hand tools such as picks, chisels, and shovels, often supplemented by limited use of gunpowder or early explosives in softer soils or rock formations where full mechanization was impractical. These methods were prevalent in historical projects, particularly ancient aqueducts and early railway tunnels, and are considered here for continuous examples exceeding 10 km, though influential shorter pioneers under 10 km are noted for establishing techniques like vertical shaft access and lining for stability. Construction demanded immense human effort, with workforces operating in hazardous conditions involving cave-ins, flooding, and poor ventilation, leading to high casualty rates; stability was maintained via timber supports, stone or brick linings, and careful surveying to ensure alignment. In contemporary engineering, purely mined tunnels over 10 km are rare, giving way to mechanized approaches for efficiency and safety. Ancient civilizations, especially the Romans, mastered mined tunneling for aqueducts to transport water across challenging terrain, often digging from both ends or using vertical shafts spaced 20–200 meters apart for ventilation and material removal. These projects involved hundreds of workers chiseling through solid rock, removing over 600,000 cubic meters of stone in some cases, and employed precise surveying tools like the chorobate level and water-filled channels for gradient control. Stability was ensured by lining interiors with (opus caementicium) and stone slabs, allowing tunnels to endure for centuries. The labor-intensive nature highlighted the era's engineering prowess, though exact workforce sizes are often unrecorded, estimated in the hundreds per major site based on shaft multiplicity.
Tunnel NameLengthLocationConstruction PeriodEstimated WorkforceStability MeasuresNotable Facts
Tunnel (Wadi es-Sallale)94 km/1st–3rd century ADHundreds (via multiple shafts) lining and stone slabsLongest known hand-dug tunnel; part of a 106 km aqueduct system supplying ancient cities, excavated by legionnaires through hard rock up to 80 m deep.
Bologna Aqueduct Tunnel18 km1st century ADHundredsStone and reinforcementExtended underground to navigate hilly terrain; up to 18 m deep, showcasing Roman multi-shaft mining techniques.
6 km (near )43–52 ADUnspecified (large teams)Monumental and liningPioneering long aqueduct emissary with service tunnels; hand-dug through for and drainage.
In the , the spurred mined railway tunnels in and , where soft clay and water-bearing strata necessitated manual excavation with iron tools and early pneumatic drills, often requiring via shafts up to 60 ft in diameter. These efforts employed thousands across sites, with workers facing frequent accidents from collapses and explosions, underscoring the method's dangers before widespread adoption of nitroglycerin or mechanized boring. Stability relied on brick arch linings and timber framing, installed progressively as excavation advanced. Though few exceeded 10 km due to time and cost, they marked a transition from ancient water conduits to transport infrastructure.
Tunnel NameLengthLocationConstruction PeriodWorkforceStability MeasuresNotable Facts
Hoosac Tunnel7.64 km (Massachusetts)1851–1875750 (in shifts)Brick lining over timber supportsKnown as the "Bloody Pit" for 196 worker deaths from explosions and collapses; first U.S. tunnel to use for blasting, costing $21 million.
Kilsby Tunnel2.29 km (Northamptonshire)1833–18381,250Brick arch lining; vertical shafts for dewateringEngineering marvel through waterlogged clay, using 15 shafts; 26 deaths, delayed London–Birmingham railway opening.

Drill and Blast Tunnels

Drill and blast tunneling involves a pattern of holes into the rock face, loading them with explosives, detonating to fragment the rock, and then mucking out the , followed by rock support installation. This method is particularly suitable for tunnels exceeding 10 km in length through variable or fractured , where flexibility in excavation allows to geological changes without the rigidity of mechanized boring. It is commonly used in formations, enabling advances of approximately 5 m per day in challenging conditions, though rates vary based on rock quality and . The cycle typically includes (2-3 hours), charging and blasting (30 minutes to 1 hour), ventilation (1-2 hours), and mucking (2-3 hours), repeating 2-3 times per shift for efficient progress. Environmental controls, such as suppression via water sprays during drilling and mucking, and ventilation systems to dilute fumes, are essential to maintain air quality and worker safety in long tunnels. Overbreak is minimized through precise , reducing the need for extensive support. Representative examples of long drill and blast tunnels include the following:
Tunnel NameLengthLocationConstruction PeriodBlast Cycle TimeRock Support
Lærdal Tunnel24.5 km (Aurland to Lærdal)1995–20006-7 hours per cycle; 60-70 m advance per week per face (2-3 rounds/day/face)Fiber-reinforced (50-100 mm thick, 40 kg/m³ steel fibers); resin-anchored rock bolts (2.5-5 m long, 25 per round); additional spalling bolts (25 mm diameter, 6 m long) in weak zones
Ryfylke Tunnel14.4 km (Stavanger region, subsea)2013–2019Approximately 5 m/day advance in ; multiple daily cycles with probe for Systematic bolting and ; pre-excavation grouting in water-bearing zones for stability
These tunnels demonstrate the method's efficacy in mountainous and subsea environments, with the serving as a benchmark for road infrastructure in variable formations.

Immersed Tube Tunnels

Immersed tube tunnels represent a specialized construction method for crossings, particularly suited to soft seabed conditions where prefabricated tunnel sections are manufactured onshore, floated to the site, and submerged into a prepared on the seafloor. This approach allows for efficient assembly in relatively shallow waters, typically less than 50 meters deep, and is ideal for lengths exceeding 5 kilometers, enabling rapid deployment compared to bored alternatives. The process involves a , placing to sink the sections, connecting them with watertight joints, and backfilling for stability, often incorporating seismic-resistant designs in vulnerable regions. Inclusion in this category requires tunnels longer than 5 km constructed via the immersed tube method, emphasizing underwater segments built from pre-cast concrete or steel elements sunk into position. Key metrics include the tunnel's total immersed length, geographic location, year of immersion completion, number of tube segments, and seabed preparation techniques such as trenching and foundation layering to ensure stability against currents and sediment.
Tunnel NameLength (km)LocationImmersion YearTube SegmentsSeabed Preparation
Tokyo Bay Aqua-Line9.6Tokyo Bay, Japan199748 concrete elements, each ~200 m longDredged trench up to 20 m deep with gravel ballast foundation for soft marine clay; artificial islands at ends for connections.
Fehmarnbelt Tunnel17.6Baltic Sea (Denmark-Germany)Under construction; immersion delayed (expected 2026 or later); full opening expected after 2029 (as of November 2025)89 elements (79 standard at 217 m, 10 special), each ~73,000 tonnes40 m deep trench dredged in glacial till; sand and gravel foundations with scour protection; multi-modal road/rail design enhances connectivity.
Hong Kong–Zhuhai–Macau Bridge (HZMB) Immersed Tunnel6.7Pearl River Delta, China201733 elements, each 180 m long (8 segments of 22.5 m)45 m below seabed trench in soft silt; mud jet mixing for foundation stabilization to resist seismic activity and vessel-induced waves.
Xiang'an Subsea Tunnel6.05Xiamen Bay, China201020 double-tube elements26 m water depth trench with 28 m overburden; cement deep soil mixing for soft seabed reinforcement.
BART Transbay Tube5.8San Francisco Bay, USA197457 steel-concrete elements, 96-112 m longDredged trench in bay mud; concrete mat foundation with gravel bedding for earthquake resilience.
These tunnels highlight advancements in watertight joint technologies, such as hydrostatic rubber gaskets and shear keys, which maintain integrity under differential settlement and hydrodynamic loads; for instance, designs in seismically active areas like the Busan-Geoje Link (though shorter at 3.7 km) influenced HZMB's earthquake-resistant joints capable of withstanding magnitude 8 events. The Fehmarnbelt project further incorporates automated immersion monitoring for precise alignment within millimeters, setting standards for future long-span applications.

Multi-level Tunnels

Multi-level tunnels feature stacked decks within a single alignment to optimize vertical space, typically for mixed transportation or functions in constrained environments. For inclusion in this list, such tunnels must exceed 5 km in total , with significant portions incorporating multiple levels (e.g., road over or dual road decks) and vertical separations of 4–10 meters between decks to allow independent operations. These designs are uncommon for extended lengths due to heightened structural demands but offer substantial efficiency gains, such as dual-mode usage that adapts to varying needs like relief or flood control. A leading example is Malaysia's Management and Road Tunnel (SMART) in , opened in 2007. Spanning 9.7 km overall with an internal diameter of 11.8 m, it includes a 4 km multi-level core where the upper deck handles two-way road traffic (two lanes per direction) and the lower deck diverts during monsoons or serves as a holding basin otherwise, with about 5 m vertical separation; a basal conduit operates continuously below. This switchable configuration exemplifies space efficiency, channeling up to 4 million cubic meters of floodwater while easing congestion on surface routes like Jalan Sungai Besi. In , the Bei Heng Motorway Tunnel in , operational since around 2012 as part of broader urban expressway expansions, measures 6.4 km and employs a double-decker layout for east-west vehicular flow under the city center and Suzhou River. Each level accommodates multi-lane road traffic, with vertical stacking enabling doubled capacity without expanding the footprint; the design integrates large-diameter shielding for stability in soft soils. Such configurations highlight multi-level tunnels' role in high-density settings, though extreme lengths remain rare owing to geotechnical and ventilation challenges. Japan's on the Central Circular Route, opened in 2015, extends 18.2 km through and incorporates vertically stacked sections over shorter segments to manage route divergences, with road decks separated by structural slabs for independent bidirectional flow. This hybrid approach, combining parallel bores with multi-level elements, supports urban ring-road functionality amid limited surface options.
Tunnel NameLocationTotal LengthOpening YearLevels/UsesVertical Separation
, 9.7 km20073 (upper: road; middle: /road; lower: )~5 m (road decks)
Bei Heng Motorway TunnelShanghai, China6.4 km~20122 (dual road decks)Not specified
Tokyo, Japan18.2 km2015Stacked road sections (partial)Slab-separated

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