"Just a Few Meters Aside"... Residents Worry About Ground Subsidence as Suwang Line Passes Under Apartment

Gangnam Segok-dong Hanyang Sujain Residents Protest Suwang Line Route
Feasibility Study Suggested Tancheon Detour, Final Plan Passes Under Apartments
Residents: "SRT and GTX Already Run Underground—Concern Over Ground Subsidence"
Conflict Mediation Filed with Anti-Corruption and Civil Rights Commission; Seoul Section Construction Delayed

Residents of Gangnam Hanyang Sujain Apartment in Segok-dong, Gangnam-gu, Seoul, are pushing back against a railway line that would run beneath their complex. The residents argue that the Seoul section of the Suseo-Gwangju double-track railway (Suwang Line), connecting Suseo Station and Gwangju in Gyeonggi Province, passes adjacent to and under the apartment complex, posing a serious safety risk such as ground subsidence.

Measuring the vertical displacement at the site claiming ground subsidence within the apartment complex. Provided by the Gangnam Hanyang Sujain Apartment Resident Committee.

According to the Gangnam Hanyang Sujain Apartment Emergency Response Committee on August 31, design blueprints obtained by the residents show the tunnel passing as close as 50 cm from the apartment buildings. The committee stated, "We are not opposed to the railway itself, but we do not want a route that tunnels directly beneath our homes without having verified the risk of subsidence." They are calling for the route to be diverted toward the nearby Tancheon stream. Last month, the residents requested collective conflict mediation from the Anti-Corruption and Civil Rights Commission.

The Suwang Line is a national railway project with a total length of about 19.4 km and a project cost of approximately 1 trillion won. The Korea National Railway is in charge, aiming to open the line in 2030. Most of the line is a subway tunnel.

According to the residents, the controversy began when the route was changed. In the 2019 preliminary feasibility study by the Korea Development Institute (KDI), the plan considered avoided the apartments by taking a detour along Tancheon. However, in late 2020, the draft environmental assessment introduced a straight route passing directly through the residential area of Segok-dong for the first time. The Korea National Railway has explained this by saying they "discovered too late that the original route would intersect with the Bundang Line, so it was changed to a straight line."

Later, during the detailed design phase, the route was adjusted again. Instead of running "directly under" the apartments, the new plan is to pass "50 cm beside" them. The stated reason in official documents was to "minimize collective complaints by not passing directly under the Sujain apartments." Residents are raising concerns, arguing that since there was originally a route that avoided the apartments and other detours are still possible, there is no reason the line must pass right next to their homes.

The primary concern and point of resistance for residents is ground subsidence. The Suseo High-Speed Railway (SRT) and the GTX-A tunnel already run under this area. With the addition of the Suwang Line, three major tunnels would overlap in a single section.

The Korea National Railway stated in materials for an online public hearing that "predicted subsidence is only 3–4 mm, which is well below the 25 mm safety standard, so the project is safe." However, residents counter that "even now, with the SRT and GTX-A passing through, subsidence of up to 150 mm has been observed," insisting that "with another line added, safety simply cannot be assured."

Residents argue that this is not an unfounded worry, citing as an example the Shinansan Line tunnel collapse accident in Gwangmyeong, Gyeonggi Province, in April last year. In April of this year, the Ministry of Land, Infrastructure and Transport's accident investigation committee pointed to poor ground surveys and errors in design load calculations as causes for that accident.

A separate controversy involves the stated distances. The draft environmental impact assessment reviewed by residents listed the distance between the apartment and the tunnel as 8 meters, but the actual design shows a distance of 50 cm—a 16-fold difference. Residents claim, "We had no idea it would be this close during the review" and allege that "the Korea National Railway knew the actual, much closer figure but wrote a farther one in the documents made public."

The underground safety impact assessment, a key safety verification step, has also come under criticism. According to the residents' analysis, Building 417—the closest to the tunnel—was omitted from the detailed safety analysis, while Building 418, which is slightly farther away, was analyzed instead, leading to the conclusion that the site was 'safe.'

Cross-sectional view of the Suin-Gwangju double-track railway intrusion at Segok 2 District Gangnam Hanyang Sujain Apartment. Provided by the Gangnam Hanyang Sujain Apartment Residents' Committee.

In the online public hearing, the Korea National Railway cited three reasons why a diversion along Tancheon is not feasible: conflicts with the Bundang Line, interference with the subway vehicle maintenance facility, and intersecting the Tancheon Ecological Landscape District. However, at a mediation meeting held by the Anti-Corruption and Civil Rights Commission on the 21st, Seoul Metro and the Seoul Metropolitan Government reportedly stated that negotiations would be possible if the railway ran beneath those facilities, and that if the railway's depth was lowered, even the Bundang Line could be avoided.

There are ongoing conflicts over procedures as well. Two scheduled public hearings for the Seoul section's environmental impact assessment have failed to take place. Most recently, a hearing set for July 30 in Segok-dong ended in disruption due to residents' protests—the second such cancellation. According to the Environmental Impact Assessment Act, if public hearings cannot be held normally at least twice, the process may be omitted entirely.

The local government has sided with the residents. The Gangnam District Council adopted a petition last May calling for a route change, and the Gangnam District Office has sent an official request to the Korea National Railway asking for future administrative steps on the project to proceed only after an agreement is reached through meetings with the Anti-Corruption and Civil Rights Commission, in order to resolve resident-government conflicts and to facilitate communication. The office also asked for active consideration to maximize resident input, including a possible route change to divert along the Tancheon stream.

Currently, only part of the project's implementation plan has been approved. In April, the Ministry of Land, Infrastructure and Transport approved only about 10 km of section from Seongnam to Gwangju, while the Seoul segment—hit by controversy—has not yet received approval as the environmental impact assessment negotiations have not been concluded.

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