THE 18.4km Sosa - Daegok extension of Seoul’s Seohae Line entered service on July 1 following an official opening ceremony held the day before in Goyang City, attended by Korea’s president, Mr Yoon Suk Yeol, as well as government officials, representatives of local authorities and construction contractors, and local residents.

Extending north from the previous terminus at Sosa in Bucheon City, the extension passes through Gimpo Airport, crosses the Han River, and terminates at Daegok in Goyang City. The line will significantly reduce journey times for residents travelling between Goyang, the Gangseo area of Seoul, and Bucheon. The first 22km Wonsi - Sosa section of the Seohae Line opened on June 16 2018.

As well as connecting two major satellite cities near Seoul, the line also serves as a vital link between western Gyeonggi and metro and rail lines. Four of the five new stations on the extension line provide interchange with Seoul Metro, including lines 3, 5, and 7, as well as the Gyeongui commuter line, the Arex express rail link to Gimpo and Incheon airports, and the Gimpo Gold Line driverless light metro.

The extension brings the number of metro or commuter lines serving Gimpo Airport to four, a number that will also be matched by Daegok station once the much-anticipated GTX-A regional express line opens in 2024.

The GTX-B line, where construction is scheduled to begin in 2024, will eventually pass through Bucheon Stadium station on the Seohae Line, while Wonjong station, the only station on the extension to Daegok without an interchange, will be served by the future Daejang - Hongdae line. Once the GTX lines open, with services operating at up to 180km/h, it is expected that the Seohae Line will play a key role carrying commuters in what was previously an underdeveloped area for urban rail.

A further extension of the Seohae Line from Daegok to Ilsan is expected to open in the near future. The importance of the Seohae Line is expected to increase further once the under-construction Songsan - Hongseong Seohaean Line and Songsan - Wonsi Sinansan Line are completed and opened by 2024 and 2025, respectively.

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