Seoul Subway Line 4 of the Seoul Metropolitan Subway is a long line crossing from the southwest to the northeast across the Seoul Metropolitan Area. The central section in Seoul City is operated by Seoul Metro with some trains offering through service to Korail's Ansan and Gwacheon Lines. The southern terminus (Oido) is in Jeongwang 4-dong, Siheung City, and the northern terminus (Jinjeop) is in Jinjeop-eup, Namyangju-si, Gyeonggi-do; the newly built northern section (officially called the Jinjeop Line) is correspondingly owned by a company owned by Namyangju-si, with operations contracted to Seoul Metro. In 2021, the Seoul Metro operated section (excluding the Jinjeop Line) had an annual ridership of 219,587,000 or about 601,608 passengers per day.

Line 4 has a similar station sign design to Busan Metro Line 2, but it has a more squashed design for its station sign, resulting in the sign appearing oblong. The number is displayed on the left side of the face, which has a pill shape, with the name (in Hangul, English, and Hanja from top to bottom) displayed in the centre-right. Two arms project from the sides, telling travellers which direction trains run and which stations are next and previous.

Express train service stops at all stations between Danggogae and Sanbon, then at Sangnoksu, Jungang, Choji, Ansan, Jeongwang, and Oido. The express service only operates during rush hours on weekdays.

History 1985: 20 April: Line 4 is officially opened from Sanggye to Sadang.

1993: 21 April: The line is extended northward from Sanggye to Danggogae, and southward from Sadang to Namtaeryeong.

1994: 1 April: The line is extended southward from Sadang to Ansan when a section of the Gwacheon Line (from Seonbawi to Indeogwon) and Namtaeryeong station open.

2000: 28 July: The line is extended westward from Ansan to Oido.

2003 18 July: Surisan station opens as an in-fill station on the Ansan Line section.

2010 Ansan Line AM express service is launched in the northbound direction only (starting from Ansan). Trains stopped at Jungang, Sangnoksu, and Sanbon, before continuing local up to Danggogae.

2014 1 September: Southbound PM express service is launched (terminating at Ansan). Trains make the same stops as their AM express service counterparts.

2017 7 July: Express service is extended to Oido. In addition to the stops they made before, trains make all stops between Ansan and Oido.

2020 12 September: Express service is modified, with trains now stopping at Choji but skipping Singiloncheon. Through service from the Suin-Bundang Line begins operation from Hayang University to Oido.

2022: 19 March: The Jinjeop Line, a northward extension of Line 4, opens from Danggogae (now Buramsan) to Jinjeop.

Future Express services are planned to start skipping various stations north of Sanbon station by 2023 to cut travel times.

Stations

Stationnumber Station name Station name EX Transfer Line name Distance Totaldistance Location Jinjeop (Kyungbok University) Onam Pungyang (2031) 풍양 ByeollaeByeolgaram Buramsan Makes all stops Sanggye Nowon Chang-dong Ssangmun Suyu (Gangbuk-gu Office) Mia (Seoul Cyber Univ.) Miasageori Gireum Sungshin Women's Univ. (Donam) Hansung Univ. (Samseongyo) Hyehwa (Seoul Nat’l Univ. Hospital) Dongdaemun Dongdaemun History & Culture Park (DDP) Chungmuro Myeong-dong (Woori Financial Town) Hoehyeon (Namdaemun Market) Seoul Station (Seoul Station branch) Mugunghwa-ho and ITX-Saemaeul services Sookmyung Women's Univ. (Garwol) Samgakji Sinyongsan (AMOREPACIFIC) Ichon (National Museum of Korea) Dongjak (Seoul National Cemetery) Chongshin Univ. (Isu) Sadang Namtaeryeong Seonbawi Seoul Racecourse Park Seoul Grand Park (Seoul Land) Gwacheon Government Complex Gwacheon Indeogwon Pyeongchon (Hallym Univ. Sacred Heart Hospital) Beomgye Geumjeong Sanbon (Wonkwang Univ. Sanbon Hospital) ● Surisan | Daeyami | Banwol | Sangnoksu (Ansan Univ.) ● Hanyang Univ. at Ansan |Suin–Bundang Jungang (Seoul Institute of the Arts) ● Gojan (Korea Univ. Ansan Hospital) | Choji (Shin Ansan Univ.) ● Ansan ● Singiloncheon | Jeongwang (Tech Univ. of Korea) ● Oido ●

Depots, junctions, and points of interest (from Jinjeop to Oido) Jinjeop Depot (for Seoul Metro-operated rolling stock) Turnback siding (underground) after Danggogae station

Non-revenue connecting track to Line 3 before Chungmuro station Dongjak Bridge Chongshin Univ. – Sadang scissors crossover Hanyang University, ERICA Campus Turnback siding (underground) after Sadang station Namtaeryong–Seonbawi track crossing point (flying crossover, switch from right to left-hand traffic, or vice versa) The voltage/current switches between DC 1,500 V ↔ AC 25,000 V Non-revenue crossover to Line 1 after Geumjeong station Non-revenue connecting track to Seohae Line before Choji station Ansan Depot (used for simple maintenance of Korail Class 341000 train) Siheung Depot (used for Korail Class 341000 maintenance and also for heavy maintenance of Korail Class 311000 trains operated on Line 1) The largest scale of shell mounds in the South Korean west coast in Oido

Rolling stock

Current Seoul Metro Seoul Metro 4000 series 2nd generation: 4-81~4-85 3rd generation: 4-50~4-70 4th generation: 4-01~4-26

Korail Korail Class 341000 (ex-Korail Class 2030) 3rd generation: 341-31~341-37 4th generation: 341-38~341-60

Former Seoul Metro Seoul Metro 3000 series (former 4000 series) Wide-width GEC Traction chopper resistor controlled electric car (1985–1993; transferred to Seoul Subway Line 3) Seoul Metro 4000 series 1st generation, DC only: 4-01~4-26 (1993-2025; restricted to between Jinjeop and Sadang) 1st generation, DC & AC: 4-51~4-71 (1993-2025)

Korail Korail Class 1000 (Ansan Line only, transferred to Seoul Subway Line 1) Korail Class 341000 1st generation: 341-01~341-25 (1993-2024) Korail Class 341000 2nd generation: 341-26~341-30 (1999-2025)

Ridership Seoul Subway Line 4 RidershipYearRidershipChange (%)Remarks2026149,570,795Updated as of June 20262025290,905,000 0.52024289,474,890 3.72023279,191,000 12.12022248,951,000 13.4Expansion to Jinjeop opens2021219,587,000 1.32020222,536,000 31.9 COVID-19 pandemic Through service with Suin-Bundang Line begins2019326,793,000 0.32018325,897,000 3.52017337,778,000 2.62016346,954,000 14.7Highest on record2015302,565,000 1.82014308,201,000 0.62013306,485,000 0.12012306,926,000 0.62011308,843,000 1.72010303,625,000 2.22009297,132,000 0.62008295,222,000 1.12007298,621,000 1.92006304,327,000 0.72005306,528,000 1.92004312,581,000 2.12003306,222,000 1.52002310,747,000 1.72001305,665,000 2.32000298,717,000 0.7Expansion to Oido opens1999296,685,000 0.51998298,268,000 21997304,436,000 -

See also Subways in South Korea Seoul Metropolitan Subway

Notes

a. One of only two subway directional crossovers in revenue service in the world, the other one located between Ho Man Tin station and To Kwa Wan station of the Tuen Ma line in Hong Kong. b. The ridership is calculated based on boarding and transferring passengers (a+c). The data tallies between the two sources but the Seoul Metro source is more granular. The ridership data is derived from the 서울교통공사 수송실적 (Seoul Metro transport performance) data/report.

References

External links Korail