Seoul pushes early ground-breaking on 6 subway lines to put stations within 10-minute walk

Seoul is moving ahead with its "3rd Urban Rail Network Plan," aimed at putting a subway station within a 10-minute walk of every resident's home. The project is set to draw a total budget of 9.2 trillion won (about $6.04 billion).

During the current eighth-term administration, Seoul has racked up a series of rail milestones: the Dongbuk Line and Wirye Line tram projects entered their final completion phases, the Ui-Sinseol extension broke ground ahead of schedule, and the Wirye-Sinsa Line and Myeongmok Line cleared preliminary feasibility reviews.

According to the Seoul Metropolitan Government on Thursday, the incoming ninth-term administration's urban rail agenda will be guided by the vision of "connecting every corner of Seoul by rail for citizens' everyday happiness." The plan pursues three goals: creating a subway environment within a 10-minute walk of every home, expanding rail stations in transit-underserved areas, and accelerating early ground-breaking on long-pending projects by strengthening their financial viability.

The 3rd Urban Rail Network Plan marks the first step toward that vision and lays out a long-term transportation blueprint aligned with the "2040 Seoul Plan" and the "Urban Renewal Project."

As a first priority, Seoul has drawn up plans for six lines — the Gangbuk Transverse Line, Nangok Line, Seonam Line, Seobu Line, Seobu Line southern extension and Sillim Line northern extension — covering a combined 68.5 kilometers at a projected cost of 9.1996 trillion won.

The Gangbuk Transverse Line, running from Mokdong Station to Cheongnyangni Station, is the longest route in the third network plan at 25.79 kilometers. Route alignment improvements will boost its financial viability, transforming it into a key corridor linking the northeastern, northwestern and southwestern parts of the city. The Nangok Line, connecting Boramae Park Station to Nanhyang-dong, will be relaunched with a revised plan to serve transit-deprived neighborhoods while securing economic feasibility.

The Seonam Line — with a main line running from Magok Naru Station to Gasan Digital Complex Station and a branch line from Seobu Truck Terminal to Dangsang Station — expands on the existing Mokdong Line plan to more effectively ease congestion in the western part of the city. For the Seobu Line, Seoul will draw on the successful model of the Wirye-Sinsa Line and explore multiple approaches, including conversion to a government-funded project, to keep the line moving forward without further interruption.

Two additional lines — the Seobu Line extension (Seoul National University Entrance Station to the main gate of Seoul National University) and the Sillim Line extension (Saetgang Station to Yeouido) — will close gaps in the network and improve rail accessibility.

The plan is expected to cut the average walking time to the nearest subway station from 9.97 minutes to 8.03 minutes, while the population within reach of the new lines would grow by 360,000 to a total of 7.83 million.

Seoul has also been actively lobbying for reforms to the preliminary feasibility study system to speed up rail project approvals. City rail projects have long struggled to clear the reviews under an evaluation framework that heavily weights economic returns. Under the proposed reform, projects would receive bonus points for "balanced regional development" and "public transit efficiency," raising the likelihood of approval.

As a result, the Ministry of Planning and Budget incorporated those criteria into its preliminary feasibility study reform package on March 10 and also updated the methodology for calculating travel-value benefits to better reflect real-world conditions. Seoul plans to use the revised system to actively advance rail projects focused on transit-underserved areas.

To finalize the 3rd Urban Rail Network Plan as quickly as possible, Seoul will conduct consultations with the Ministry of Land, Infrastructure and Transport and other relevant agencies, as well as gather input from the Seoul Metropolitan Council. A public hearing is also scheduled for June 30 at the Seosomun Annex of Seoul City Hall.

Following the hearing, the city will move into full administrative procedures in the second half of the year, including the approval process with the Ministry of Land, Infrastructure and Transport. The goal is to maximize feasibility and ensure project continuity — with no stoppages or delays — by applying Seoul's accumulated expertise in urban rail development, including streamlined procedures.

In addition, Seoul plans to review the feasibility of introducing the Dongbu Line, a new light rail route linking Gangnam and Gangbuk, by incorporating the latest ridership demand data before pursuing it through an amendment to the third network plan.

"Building on the track record and strong resolve we have demonstrated during the eighth term, I will spare no effort to advance rail projects without a hitch," Seoul Mayor Oh Se-hoon said. "We will push ahead swiftly with expanding rail infrastructure and innovating transit services to make a tangible difference for citizens and lead an overwhelming transformation of Seoul's transportation landscape."