Seoul Subway Line 7 of the Seoul Metropolitan Subway was built from 1990 to 1996 (Jangam-Konkuk Univ.) and was completed on August 1, 2000 (central section 17 km (11 mi). Konkuk University to Sinpung); the western section between Sinpung and Onsu was put into service on February 29, 2000. This north-south line does not run through the city centre but links Gangnam directly to the northeastern districts of Seoul. In 2019, Line 7 had an annual ridership of 380 million or 1.04 million passengers per day.[1] Although most trains run between Jangam and Seongnam, some trains short turn at Onsu station and some trains start at Dobongsan station.
All trains on Line 7 are monitored by 1,008 closed-circuit television cameras that were installed in June 2012.[2]
The extension to Incheon Subway Line 1 was designed to relieve the traffic congestion in western Seoul and northern Incheon. Nine stations were added on October 27, 2012, for the 10.2 km (6.3 mi) extension, starting from Onsu Station of Line 7 and ending at Bupyeong-gu Office Station of Incheon Subway Line 1.[3]
Line 7 was extended west of Bupyeong-gu Office. Construction on the two-station, 3.94 km (2.45 mi) extension to Seongnam began in 2013 and was completed on May 22, 2021.[4] The extension allows for transfers to Incheon Subway Line 2.
A further seven-station extension to Cheongna International City station through Cheongna International City is currently planned and is not expected to open any earlier than 2027; the extension will allow for transfers to the airport railroad. Another further two-station extension through Incheon's metropolitan landfill to Geomdan Oryu station is also currently being planned.
Line 7 is also being extended north of Jangam to Yangju and Pocheon in two phases. The first phase, which started construction in late 2019 and is planned to open in 2025, will feature two stations, one of which will be Tapseok station, providing transfers to the Uijeongbu LRT. The second phase, which is still in planning, will feature four additional stations. The second phase may be operated as a shuttle service.[5]
Although the line is mostly operated by Seoul Metro, the section beyond Onsu, between Kkachiul and Seongnam (including the future extension to Cheongna Int'l City) is operated by Incheon Transit Corporation.[6] Further, this section was funded as Bucheon and Incheon City metro, is considered a part of Incheon Metro rather than as a part of Seoul Subway, and serves as an east-west line through wider Incheon area.
Despite this, the entire line is operated as one, with all trains in the Incheon-operated section continuing onto the Seoul-operated section. Approximately half of trains in the Seoul-operated section continue onto the Incheon-operated section.[7]
