Missing Rebar Delays Seoul’s GTX-A Through Trains to 2027 at the Earliest

Photo: Brit in Seoul, Wikimedia Commons, CC BY-SA 4.0 (file photo, 2017). Office towers near Samseong Station in Gangnam, Seoul. The image shows the station area, not the underground GTX-A works.

Trains on Seoul’s GTX-A express line will not run straight through the unfinished Samseong Station until the first half of 2027 at the earliest, after inspectors found columns missing large numbers of steel reinforcing bars. South Korea’s Ministry of Land, Infrastructure and Transport said on Tuesday, Nov. 3, that it will decide by the end of this year whether to reinforce the columns or tear them down and rebuild them. The 2027 timeline assumes the existing columns can be kept and strengthened, Asia Business Daily reported.

The ministry had aimed for through service by June 2026. That date was later pushed to August before the latest delay, Korea JoongAng Daily reported.

A line split in two

GTX-A is a high-speed commuter rail line meant to cut travel times across the Seoul region to about 30 minutes. For now it runs as two separate sections. One goes from Unjeongjungang Station in Paju, northwest of Seoul, to Seoul Station. The other runs from Suseo Station in Gangnam District to Dongtan in Hwaseong, south of the capital.

Samseong Station sits in the gap between them, under Yeongdong-daero in Gangnam, directly in front of the Coex convention and shopping complex. Through service means trains would pass Samseong without stopping. Riders could then travel from Paju to Dongtan without changing trains, but they still could not get on or off at Samseong.

The station itself is further off. Temporary transfers at Samseong had been planned for 2027 and the full opening for the end of 2028. Both are now expected to slip by more than a year, JoongAng Daily reported.

How the problem came to light

Hyundai Engineering & Construction, the contractor, first confirmed on Oct. 23, 2025, that reinforcing bars were missing from underground columns in Section 3 of the Yeongdong-daero underground development project, Asia Business Daily said. It reported the problem to the Seoul Metropolitan Government, together with the construction supervisors, on Nov. 10, 2025.

A joint government inspection team has been examining all four sections of the project since May 21, 2026, The Financial News reported. The review covers the design, construction, fire and electrical safety, and the causes of the errors. It has also flagged other problems that may need more reinforcement, including concrete cover that is too thin and questions about whether columns can bear their loads. The contractor has already fixed smaller issues, such as improperly installed safety railings.

Two repair options left, plus a rebuild study

The Korea Concrete Institute began reviewing 12 repair proposals on May 28. One came from the Seoul city government, which proposed bolting steel plates to the outside of the columns. That method was used on 162 columns at Gongdeok Station around 2014, when facilities above the station were expanded.

The institute concluded the Gongdeok method could not simply be copied at Samseong, Asia Business Daily reported. So many bars are missing at Samseong that the columns lack enough load-bearing capacity, and steel plates on the outside alone have limits.

The institute narrowed the list to two options:

• Thicker columns: coating the columns with a high-strength special mortar to enlarge their structural core.
• Composite repair: combining the mortar with steel plates wrapped around the columns.

Engineers are building full-size column models to test the mortar’s strength and whether it can completely fill the gaps. Separately, the Korean Society for Structural Maintenance and Inspection is studying the option of demolishing and rebuilding the columns. Rebuilding would push the schedule further back.

“We will thoroughly inspect and review the construction errors at Samseong Station with public safety as our top priority,” said Kim Tae-byeong, the ministry’s director general for railway policy, according to JoongAng Daily. He said the ministry would choose the best option by year-end “while also taking public convenience” into account.

Penalties for the contractor

The ministry plans to finish reviewing the guideline and rule violations found in the inspection by the end of the year. It will then impose penalty points on the contractor and take other administrative action, Asia Business Daily and The Financial News reported. Exact dates for through service will be set once a repair method is chosen.

Why it matters

The delay shows how one defective station can hold up an entire regional rail line. Boston riders know the pattern. Repairs and upgrades regularly force closures on the MBTA, including a nine-day light-rail shutdown starting Nov. 7, with replacement shuttles. In Seoul, TBR also covered how trains skipped Itaewon Station during Halloween crowds. More regional coverage is in TBR’s Asia-Pacific news section.

Sources

• Asia Business Daily: GTX-A Samseong through service pushed to first half of 2027
• Korea JoongAng Daily: Full operations of express GTX-A derailed again
• The Financial News: Year-end decision on reinforcing or rebuilding GTX Samseong columns

Additional sources

• SBS News: GTX-A Samseong delay
• Yonhap: GTX-A Samseong Station schedule (Korean)