Seoul Subway Line 1

Line 1
Seoul Metro 1000 series EMU in December 2017 (bottom) Korail Class 311000 series EMU in February 2021 (top)
Overview
Native name	1호선(一號線) Il Hoseon
Status	Operational
Owner	Seoul Special City, South Korean Government
Line number	1
Locale	Seoul Capital Area
Termini	Yeoncheon Incheon / Sinchang / Gwangmyeong / Seodongtan
Stations	102 Seoul Metro: 10 Korail: 92
Service
Type	Rapid transit / Commuter Rail
System	Seoul Metropolitan Subway
Services	Local: Yeoncheon / Soyosan / Dongducheon ↔ Incheon, Kwangwoon U ↔ Seodongtan / Cheonan / Sinchang, Yeongdeungpo ↔ Gwangmyeong Express: Cheongnyangni ↔ Cheonan / Sinchang, Dongducheon ↔ Incheon (AM Rush & off-peak weekdays), Yongsan ↔ Dongincheon, Seoul Station ↔ Cheonan/Sinchang (weekday RH, peak direction only)
Operator(s)	Seoul Metro, Korail
History
Opened	August 15, 1974
Technical
Line length	218.3 km (135.6 mi) Seoul Metro: 7.8 km (4.8 mi)[1] Korail: 210.5 km (130.8 mi)
Track gauge	1,435 mm (4 ft 8+1⁄2 in) standard gauge
Electrification	1,500 V DC (Seoul Metro section) 25 kV AC at 60 Hz (Korail section)
Operating speed	110 km/h (68 mph)
Route map Legend Gyeongwon Line ↑Yeoncheon/Dongducheon↓ 0.0 Soyosan 2.5 Dongducheon 4.1 Bosan 5.5 Dongducheon Jungang 6.5 Jihaeng 12.1 Deokjeong 15.0 Deokgye Majeon Signal Box 20.3 Yangju 21.9 Nogyang ←Gyooe Line 23.2 Ganeung 24.4 Uijeongbu 26.0 Hoeryong 27.4 Mangwolsa ↑Uijeongbu/Seoul↓ 29.7 Dobongsan 30.9 Dobong 32.2 Banghak 33.9 Chang-dong 34.9 Nokcheon 36.3 Wolgye formal Gyeongchun Line 37.4 Kwangwoon Univ. 38.5 Seokgye Imun Rail Yard 39.9 Sinimun Mangu Line(     Gyeongchun Line)→ 40.7 Hankuk Univ. of Foreign Studies      Gyeongui–Jungang Line      Gyeongchun Line→ 41.5 Hoegi ↑AC section/DC section↓ (neutral section)      Gyeongui–Jungang Line      Gyeongchun Line 42.9 Cheongnyangni      Gyeongui–Jungang Line→ 43.9 Jegi-dong connection line→ 44.8 Sinseol-dong 45.5 Dongmyo Since 2005 46.1 Dongdaemun 46.9 Jongno 5(o)-ga 47.8 Jongno 3(sam)-ga 48.6 Jonggak 49.6 City Hall (↖)Gyeongui Line, (→) 50.7 Seoul Station (←), (→) ↑DC section/AC section↓ (neutral section) 52.4 Namyeong ←     Gyeongui–Jungang Line 53.9 Yongsan Yongsan Triangular line Yongsan Rail Yard (closed) Han River 56.5 Noryangjin 58.0 Daebang 58.8 Singil 59.8 Yeongdeungpo 61.3 Sindorim 62.4 Guro ←Gyeongin (to Incheon) Guro Rail Yard Northbound/Southbound 64.8 Gasan Digital Complex 66.8 Doksan 68.0 Geumcheon-gu Office ←Gyeongbu high-speed railway (Siheung connecting line) (72.7) Gwangmyeong 70.3 Seoksu 72.2 Gwanak 74.6 Anyang 76.8 Myeonghak → 78.2 Geumjeong ← 80.4 Gunpo 81.6 Dangjeong 84.6 Uiwang 87.5 Sungkyunkwan Univ. 90.1 Hwaseo 92.2 Suwon      Suin–Bundang Line 95.1 Seryu 99.4 Byeongjeom Byeongjeom Rail Yard (101.6) Seodongtan 101.8 Sema 104.5 Osan Univ. 107.2 Osan 111.2 Jinwi 115.0 Songtan 117.2 Seojeongni 122.0 PyeongtaekJije 125.7 Pyeongtaek 135.1 Seonghwan 140.5 Jiksan 144.3 Dujeong 147.3 Cheonan Gyeongbu Line (to Daejeon→ 148.8 Bongmyeong 150.3 Ssangyong 151.8 Asan ←Gyeongbu high-speed railway→ Tangjeong 156.7 Baebang 161.6 Onyangoncheon 166.7 Sinchang Janghang Line (to Iksan station)

Seoul Subway Line 1 (dubbed The Dark Blue Line) of the Seoul Metropolitan Subway is a rapid transit and commuter rail line which links central Seoul, South Korea to Yeoncheon in the northeast, Incheon in the southwest, and Sinchang via Suwon and Cheonan in the south. The central underground portion of Line 1, running underneath Sejongno, Jongno, and Wangsan-ro avenues along Seoul's traditional downtown area, is the oldest subway-operated section in the Seoul Metropolitan Subway system. Its branches and services cover a large part of the Seoul Capital Area; totaling 218.3 km (135.6 mi) in route length.

The underground section between Seoul Station and Cheongnyangni station, which is referred to as Seoul Metro Line 1 (7.8 km [4.8 mi]) after its operator, is currently operated by Seoul Metro, and is electrified at the subway standard of 1.5 kV DC.^[1][2] The line first opened in 1974 as the Korean National Railroad of Seoul with through services to newly-electrified (at the mainline KNR standard of 25 kV AC 60 Hz) national mainline railways from Seongbuk station (now: Kwangwoon University station) to Incheon and Suwon Stations.^[3] This was the first electrified rapid transit line and service in South Korea and the second in the Korean Peninsula after the Pyongyang Metro in North Korea opened the year before.

Frequent service is provided between Soyosan, Dongducheon, Uijeongbu, Cheongnyangni, Seoul, Yongsan, and Guro, where trains split between Incheon in the west and Byeongjeom and Cheonan in the south. Express trains operate from Yongsan and Seoul stations to Dongincheon and Sinchang stations. Trains run every 3-6 min in the central route between Seoul Station and Cheongnyangni, every 6-9 min between Seoul and Guro, every 8-10 min between Guro and Incheon and between Guro and Byeongjeom, every 10-15 min from Byeongjeom to Cheonan, and every 35 min between Cheonan and Sinchang and service up to the Dongducheon area and Soyosan station.

Service to Yeoncheon is approximately once per hour, limited due to the single track section approaching Soyosan station. This service is meant to be the replacement for the Gyeongwon line commuter trains, which began at Dongducheon station prior to its closure.

Trains travel along Gyeongbu (Seoul-Cheonan), Gyeongin (Guro-Incheon), Janghang (Cheonan-Sinchang), and Gyeongwon (Hoegi-Yeoncheon) railway lines. The line runs on the left-hand side of the track, as opposed to the right-hand side of the track like all other Seoul Metropolitan Subway lines (another exception to this is Seoul Subway Line 4 although it runs on the right-hand side until Namtaeryeong station, and operates on the left-hand side for the parts afterwards)^[4] since railways in Korea generally run on the left side.