Great Train eXpress

Great Train eXpress (GTX) is a higher-speed commuter rail network in the Seoul Capital Area project consisting of three separate lines, named GTX-A, GTX-B and GTX-C, and scheduled for completion in 2030. Three other lines, named GTX-D, GTX-E and GTX-F are being planned.

GTX-A
Groundbreaking for GTX Line A was held on December 27, 2018, with service initially expected to commence in 2023. However, the project has been officially delayed due to land compensation issues and the discovery of archaeological ruins dating from the Joseon period. Suseo, Seongnam, and Dongtan stations were opened on March 30, 2024, and Guseong Station opened on June 29, 2024. The northern section of the line is anticipated to open late 2024 with the connection between Seoul Station and Suseo opening at the end of 2026. Samseong Station has been further delayed and will remain closed until 2028, even after the rest of GTX-A opens. Approximately 30 kilometers of the line are expected to share the same rail as the SRT, and an additional 9 kilometers towards the western end of the route are expected to be completely underground.

GTX-B
Construction of GTX Line B commenced on March 7, 2024. It is planned to be completed by 2030.

GTX-C
Construction of GTX Line C commenced on January 25, 2024. It is planned to be completed by 2028. According to the latest plans and following the selection of a preferred bidder for the construction of this line, 2 additional stations, Indeogwon Station and Wangsimni Station are likely to be added to the line.

Additional plans for other lines
Plans for a Line D were announced in 2021 by the previous government. However, the proposed route faced a lot of opposition, and has not been approved yet. The new government of Yoon Seok-youl has pledged to build 3 new lines (Lines D, E and F), for which the routes have not been decided yet, but which would likely include plans for a longer Line D than the one announced by the previous government. Plans for a Line G and H that will expand to the northern and southwestern regions of Gyeonggi Province have also been announced.

Criticism
Critics argue that GTX project would increase the social and economic centripetal force towards Seoul leading to increased primacy and the collapse of other provincial cities.