Ulsan tram project picks up speed with depot relocation plan

Ulsan's urban railway (tram) Line 1 project, which had been thrown off track by a stop-and-restart cycle since the ninth directly elected administration took office, is now accelerating after the city moved to relocate its planned maintenance depot, putting controversy over the project to rest.

Ulsan city held a press conference Monday at the main city hall building and announced it would pursue relocating the Line 1 depot from its originally planned site at Taehwagang Station square to an alternative location. The city cited two reasons: high-pressure gas pipelines are buried beneath the square, and the ground there consists of soft soil, meaning that moving the pipelines and improving the subsoil would require significant time and money.

Under the current plan, the Line 1 depot was to be built on a 23,595-square-meter plot at Taehwagang Station square at a cost of 38.3 billion won ($28.5 million), with a total floor area of 9,976 square meters housing a central management building, an inspection shed, a washing facility, a hydrogen charging station and a substation.

Taehwagang Station square was originally chosen for the depot for five reasons: the site had been developed to accommodate a depot; hydrogen pipelines needed for the line's hydrogen-electric trams were already in place along Saneop-ro in front of the square; the site's designation as an urban transportation facility simplified administrative procedures; it is city-owned land, eliminating the need for compensation; and its flat terrain would reduce project costs and allow construction to begin immediately upon contract signing.

However, contractor Hanshin Construction recently found during the design process that relocating the underground obstacles and improving the soft ground could significantly extend the construction timeline.

The investigation found that moving a Korea Gas Corporation high-pressure natural gas pipeline — 762 millimeters in diameter and 357 meters long — running through the site would take two years and cost an estimated 5.8 billion won. The square also sits on soft ground composed of fill soil, cohesive clay and sedimentary layers, making subsidence likely under the permanent load of structures and the long-term load of trams parked overnight, with ground improvement work also estimated to take two years.

As a result, the project would require a minimum of six years (72 months) — two years for pipeline relocation, two years for ground improvement and two years for depot construction — some 27 months longer than the current 45-month schedule. Pipeline relocation costs, inflation and indirect expenses are expected to add more than 30 billion won to the overall project cost.

After weighing the extended timeline, higher costs and resulting inconvenience to residents, Ulsan city concluded that relocating the depot is unavoidable and plans to amend the project design by identifying the most suitable site along the Line 1 route where construction can be completed within the original schedule. However, the hydrogen charging station will still be built at Taehwagang Station square as originally planned, given the existing hydrogen pipeline infrastructure there.

In addition, the city plans to release legal advice it has received on liability for delay damages arising from the project plan change, keeping residents fully informed of the process and the reasons the revision is unavoidable.

"We have no choice but to find an alternative site to keep the project moving smoothly and minimize inconvenience to residents," said Kim Chang-hyeon, head of Ulsan's transportation bureau. "We will select the most suitable depot location along the Line 1 route where construction can be completed within the project timeline."