Seoul to invest 9.2 trillion won in six new urban rail lines

The Seoul Metropolitan Government is pushing ahead with its "Third Urban Rail Network Construction Plan," aimed at giving every resident access to urban rail within a 10-minute walk from home. The project is set to draw a total budget of 9.2 trillion won (approximately $6.06 billion).

During the eighth elected-term administration, Seoul made significant strides in urban rail development — entering the final construction phase for the Dongbuk Line and Wirye Line tram, fast-tracking the groundbreaking of the Ui-Sinseol Extension, and securing preliminary feasibility approval for the Wirye-Sinsa Line and Myeongmok Line.

According to the Seoul Metropolitan Government on Wednesday, the urban rail agenda for the incoming ninth elected-term administration carries the vision of "a happy daily life connected by rail from anywhere in Seoul." Its goals are to create a subway-within-10-minutes-of-home environment, expand rail stations in transit-underserved areas, and accelerate the groundbreaking of long-awaited local projects by strengthening their financial viability.

The third urban rail network plan marks the first step toward that vision, the city said, and is designed to chart a future course for transport development in preparation for the "2040 Seoul Plan" and the "Urban Renewal Project."

Seoul has earmarked 9.1996 trillion won for six lines with a combined length of 68.5 km: the Gangbuk Transverse Line, Nangok Line, Seonam Line, Seobu Line, Seobu Line Southern Extension, and Sillim Line Northern Extension.

The Gangbuk Transverse Line, running from Mokdong Station to Cheongnyangni Station, is the longest route in the third network plan at 25.79 km. Through alignment improvements and other measures to boost financial viability, it will become 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 revived with a focus on serving transit-underserved communities while securing financial sustainability.

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 Dangsan Station — expands on the existing Mokdong Line plan to more effectively ease congestion in the western part of the city. For the Seobu Line, the city will draw on the successful model of the Wirye-Sinsa Line and explore multiple approaches, including conversion to a publicly funded project, to ensure the line proceeds without further interruption.

Two extension 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 feasibility threshold under an evaluation framework weighted heavily toward economic returns. The proposed reforms are expected to award bonus points for "balanced regional development" and "public transport system efficiency," raising the likelihood of approval.

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

To finalize the third urban rail network plan as quickly as possible, the city will consult with the Ministry of Land, Infrastructure and Transport and other relevant agencies, and hold a Seoul City Council hearing. A public forum is also planned for June 30 at the Seosomun Annex of Seoul City Hall.

Following that, the city will move into the formal administrative process, including seeking Ministry of Land, Infrastructure and Transport approval in the second half of the year. The goal is to maximize feasibility and maintain project continuity without interruption or delay, drawing on Seoul's accumulated expertise in streamlining urban rail procedures.

In addition, the city 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, with a view to adding it through a revision to the third network plan.

"Building on the track record and strong resolve demonstrated during the eighth elected-term administration, I will spare no effort to keep rail projects on track without disruption," Seoul Mayor Oh Se-hoon said. "We will push forward swiftly to expand rail infrastructure and transform public transport services, so that residents feel the difference and Seoul leads an overwhelming era of transport transformation."