Construction of elevated light rail tracks in Tukwila moving forward

Construction of Sound Transit's elevated light rail trackway in Tukwila resumed on Wednesday following a one-day delay, and on Saturday crews re-launched a critical piece of equipment following the completion of repairs.

After fully hoisting into place the pre-cast concrete segments forming a span between two columns, crews moved the 400-foot-long gantry that is building the elevated Tukwila tracks to the top of the next column to begin a new span.

“We're pleased that our contractor, PCL Construction Services, was able to quickly perform the needed repairs and get the gantry operational again with a net loss of only one workday,” said Sound Transit Link Light Rail Director Ahmad Fazel. “PCL did a good job of responding to the problem rapidly while taking a safety-first approach.”

Work was temporarily stopped on Monday, Aug. 7 after a hydraulic problem that caused equipment that was being lifted to the top of a column to slowly slip into a non-level position. The gantry and its equipment were not in danger of falling, and there were no injuries or damage. PCL crews quickly took precautionary actions to support and level the equipment. Inspection and repair of the hydraulic unit began the next day after a crane moved the suspended equipment to the top of the column, and on Wednesday PCL was able to resume work to install the elevated light rail segments at the same time the hydraulic repairs proceeded. The repairs were completed, and the crew launched the gantry after an in-depth review by the contractor and Sound Transit.

The five-mile Tukwila light rail segment that PCL is building features an innovative design based on pre-cast concrete segments. Moving from column to column, the gantry hoists the approximately 30-ton concrete segments into place and supports them while they are connected and fastened into place with post-tensioned steel cables. A typical span between two columns is formed by 12 segments. When a span is completed PCL extends the gantry forward to the top of the next column and the process is repeated. So far PCL has used the gantry to install about one mile of elevated light rail trackway.

Starting in 2009 light rail will provide fast and reliable transit service to the residential and employment centers along the 15.6-mile route between downtown Seattle and Sea-Tac International Airport. The segment between downtown and Tukwila is on track to open for passenger service as scheduled in Summer 2009. The 1.7-mile Airport Link extension is on schedule to open in December 2009.

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Sound Transit plans, builds, and operates regional transit systems and services to improve mobility for Central Puget Sound.