Seoul Metropolitan Subway Line 1

Opened in 1974 as Korea's first urban railway, it is a metropolitan rail line connecting the Seoul metropolitan area and South Chungcheong Province using the Gyeongbu, Gyeongin, Gyeongwon, and Janghan

Seoul Metropolitan Subway Line 1 (수도권 전철 1호선)

Overview

Seoul Metropolitan Subway Line 1 (수도권 전철 1호선) is the first urban railway line in the Republic of Korea, opened on August 15, 1974. It is a metropolitan commuter rail system operated by combining the underground section in central Seoul with existing national railway networks such as the Gyeongbu Line, Gyeongin Line, Gyeongwon Line, and Janghang Line. It consists of multiple service branches running from Yeoncheon, Dongducheon, and Soyosan to Incheon and Sinchang (Cheonan), and with a total length exceeding 200 km and more than 100 stations, it is one of the longest urban railway lines in the world. Its average daily ridership is around 1 million, and it serves as a core axis of public transportation in the Seoul metropolitan area.

Main Details

Route Composition and Sections

Line 1 is broadly divided into the underground section between Seoul Station and Cheongnyangni (under the jurisdiction of Seoul Metro) and the above-ground sections elsewhere (under the jurisdiction of Korail). To the north it extends along the Gyeongwon Line toward Yeoncheon, Dongducheon, Uijeongbu, and Changdong; to the west it extends along the Gyeongin Line toward Guro, Bupyeong, and Incheon; and to the south it extends along the Gyeongbu and Janghang Lines toward Suwon, Pyeongtaek, Cheonan, and Sinchang. Its greatest characteristic is that different service branches run in parallel under a single line name, with express and local trains sharing the same tracks.

History

In 1899, the Noryangjin–Jemulpo section of the Gyeongin Line opened, marking the beginning of Korean railway history, and the Gyeongbu Line was laid in the 1900s. On August 15, 1974, the Seoul Station–Cheongnyangni underground section and portions of the Gyeongin and Gyeongbu Lines were electrified, officially opening Seoul Metropolitan Subway Line 1, which is recorded as Korea's first urban railway service. Afterwards, electrification of the Gyeongwon Line in the 1980s, extensions to Uijeongbu, Suwon, and Byeongjeom in the 1990s, and extensions to Cheonan–Sinchang and Soyosan in the 2000s were carried out in stages, and in December 2023, with the opening of Yeoncheon Station, the double-track electrified Gyeongwon Line between Dongducheon and Yeoncheon was completed, further expanding the line.

Service Branches and Rolling Stock

Representative branches include the Incheon–Soyosan (Dongducheon) branch, the Sinchang–Cheongnyangni (Kwangwoon University) branch, and the Byeongjeom–Seodongtan shuttle branch. Rolling stock includes Korail Class 311000 electric multiple units and Seoul Metro Class 1000 electric multiple units, and aging rheostatic and chopper-controlled cars have been retrofitted or replaced with VVVF-controlled cars. Because the above-ground sections are long, securing priority for express trains and managing track capacity are regarded as important operational challenges.

Operating Agencies and Fare System

It is a dual system in which Seoul Metro operates the underground section in central Seoul and Korail operates the above-ground and outer sections, and the Seoul metropolitan integrated transfer discount system applies. Base fares apply based on standard transportation cards, and it is also linked with period passes and refund-type transportation cards such as the Climate Card and K-Pass, with distance-based section fares added on top. Platform screen doors and real-time train arrival information systems are installed at most stations.

Major Transfer Hubs

Seoul Station, Cheongnyangni Station, Changdong Station, Guro Station, Yeongdeungpo Station, Bupyeong Station, Suwon Station, and Cheonan Station are representative transfer hubs. At these stations, passengers can transfer to Lines 2, 3, 4, and 7, the Bundang Line, the Suin Line, the Shinbundang Line, and KTX and ITX services, among others, making them key nodes for metropolitan travel in the capital region.

Recent Trends

In December 2023, the opening of the double-track electrified Gyeongwon Line between Dongducheon and Yeoncheon extended the operating range to Yeoncheon Station, and in 2024–2025 improvements to aging tracks and signaling equipment and the introduction of new electric multiple units are continuing. The application of smart operating technologies, such as the disclosure of real-time train crowding levels and the upgrading of intelligent CCTV and control systems, is also expanding. As transfer connections with the GTX-A, B, and C lines are being pursued centering on Seoul Station, Cheongnyangni, and Changdong, the division of roles with the metropolitan express railway has emerged as a major topic of discussion. Meanwhile, discussions continue over expanding the scope of Climate Card application and adjusting fares, and demands continue to be raised for expanding express train stops and increasing service frequency to alleviate rush-hour congestion, while the establishment of a transfer system with new lines such as the Shinansan Line is also underway with the goal of opening in 2026.