South Korea, October 2026 — South Korea is advancing construction of its South Coast Inland Railway, a regional rail development intended to strengthen transport connectivity along the country’s southern coast. Ssangyong Engineering & Construction was selected on 29 September 2026 to lead the roadbed construction for Section 9, under a contract valued at approximately 806.5 billion won.
The 24.6-kilometre section will connect Goseong-eup in South Gyeongsang Province with Sadeung-myeon on Geoje Island. The entire alignment is planned as a tunnel, including a 2.9-kilometre undersea section that will use shield tunnel boring machine technology. Construction is scheduled to take 60 months from the groundbreaking date.
Ssangyong E&C will hold a 45% stake in the project and serve as the lead contractor. KCC E&C holds 15%, while eight other companies will each hold a 5% share. The contract adds to Ssangyong E&C’s involvement in the South Coast Inland Railway, following earlier awards for Sections 5-2 and 8-2 in January 2026.
The project draws on the contractor’s experience in large-scale railway and underground infrastructure, including the application of large-diameter tunnel boring machines on the Pyeongtaek–Osong quadruple-tracking project. The undersea section will require specialised engineering and construction controls to address geological conditions, water pressure and the demands of building a continuous railway tunnel beneath the seabed.
The development highlights South Korea’s continued investment in regional rail connectivity and advanced tunnelling methods. As construction progresses, the project will demonstrate how shield TBM technology can be applied to complex railway alignments, potentially informing future infrastructure projects involving coastal terrain and undersea connections.
Source: CHOSUNBIZ
South Korea Advances Undersea Tunnel Construction For Coastal Railway
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Railway infrastructure projects increasingly rely on specialised tunnelling technologies to overcome challenging coastal terrain and improve connectivity between regional centres. South Korea has awarded a major construction contract for Section 9 of its South Coast Inland Railway, including the country’s first undersea shield tunnel built using a tunnel boring machine for a railway project.
