'8 Minutes to the Subway'... Seoul to Invest 9.2 Trillion Won in Gangbuk and Southwest Railway Network

Establishment of the 3rd Urban Railway Network Construction Plan
Six Railway Projects Including Gangbuk Transversal Line and Nanggok Line
Total Length of 68.5 km, Project Cost of 9.1996 Trillion Won
Approval by Ministry of Land Targeted After Public Hearing on the 30th

The Seoul Metropolitan Government is set to move forward with six urban railway projects, including the Gangbuk Transversal Line and Nanggok Line, with an investment of 9.2 trillion won. The plan aims to connect transportation-disadvantaged areas in the Gangbuk and southwestern regions, supporting balanced development. The city aims to reduce the average access time to subway stations to 8 minutes.

On June 11, the Seoul Metropolitan Government announced that it has prepared the “3rd Urban Railway Network Construction Plan” and submitted it to the Seoul Metropolitan Council.

The six projects consist of the Gangbuk Transversal Line, Nanggok Line, Mokdong Line (Southwest Line), Seobu Line, Seobu Line Southern Extension, and Sillim Line Northern Extension. While these projects have long been anticipated by residents in the Gangbuk and southwestern parts of Seoul, they have stagnated due to low economic feasibility. This time, the city improved economic viability by reducing the number of stations or revising routes. The total length is 68.5 kilometers, and the total project cost is 9.1996 trillion won.

Although Seoul boasts a world-class urban railway infrastructure, some disadvantaged areas still require over 10 minutes to reach a subway station. There is an urgent need to create alternative routes due to insufficient connectivity and direct links between the city’s three main hubs. In response, the city reviewed 250 routes, taking into account demand in the affected areas, overlapping segments, technological conditions, and the railway plans of the central government and neighboring local governments. Based on comprehensive reviews of economic feasibility and policy alignment, the city ultimately selected six final routes.

The Gangbuk Transversal Line, running 25.79 kilometers from Mokdong Station to Cheongnyangni Station, is the longest among the third-phase railway network projects. The city has enhanced business feasibility through route improvements, promoting it as a key line traversing the northeast, northwest, and southwest regions. Although this line has been under review since the 2nd Urban Railway Network Plan, it struggled due to low project feasibility. Despite strong commitment from the city, the central government’s preliminary feasibility study found insufficient economic justification (Benefit/Cost), preventing construction from starting. In the third-phase plan, the city reduced the number of stations by two and incorporated 49 future development plans to improve the project’s viability.

The Nanggok Line connects Boramae Park Station to Nanhyang-dong. The city reduced the number of stations from six to five and updated development plans, including Sillim District 7, to enhance economic feasibility.

The Southwest Line is an expansion of the existing Mokdong Line plan. The main line is planned from Magoknaru Station to Gasan Digital Complex Station, and the branch line from Seobu Truck Terminal to Dangsan Station. The city extended both northern and southern end points of the original Mokdong Line and factored in demand from the Mokdong redevelopment area.

For the Seobu Line, the city will simultaneously proceed with a renewed public-private partnership announcement and a transition to a publicly financed project to ensure uninterrupted progress. The Seobu Line Southern Extension will connect Seoul National University Station to the university’s main gate, while the Sillim Line Northern Extension will link Saetgang Station to Yeouido, improving rail access in previously disconnected areas. Although not included in the third-phase railway network plan, the city will pursue the introduction of the new Dongbu Line, a light rail line connecting Gangnam and Gangbuk, after assessing its feasibility based on the latest demand and amending the third-phase plan accordingly.

The Seoul Metropolitan Government expects that, upon completion of the 3rd Urban Railway Network, the average access time to subway stations will be reduced from 9.97 minutes to 8.03 minutes. The beneficiary population within the new lines’ area of influence is projected to increase by 360,000 to a total of 7.83 million people.

The city plans to expedite administrative procedures with the goal of securing approval from the Ministry of Land, Infrastructure and Transport in the second half of the year. On June 30, a public hearing will be held at the Seosomun Building of Seoul City Hall to gather public opinions. Jangkwon Yeo, Seoul's policy chief for transportation, stated, “With the inclusion of regional balanced development and public transit system efficiency in the preliminary feasibility study reform plan announced by the Ministry of Economy and Finance in March, we expect the likelihood of the third-phase plan passing the preliminary feasibility study to increase.”

Seoul Mayor Oh Se-hoon said, “We will swiftly and seamlessly expand railway infrastructure and innovate transportation services to enhance the public’s experience and lead Seoul into a new era of overwhelming transportation transformation.”

This content was produced with the assistance of AI translation services.