New time-lapse video shows how huge crane speeds up light rail construction

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South 200th Link Extension's elevated tracks rely on precast concrete segments

 A new time-lapse video that compresses eight hours into three minutes offers a visually stunning answer for anyone who has wondered how a new section of elevated light rail trackway can go up so quickly.  

The video showcases construction of the aerial trackway for the future Angle Lake light rail station. Rather than the more typical bridge construction method of pouring concrete, crews are making shorter work of the 1.6-mile light rail extension between the airport and South 200th Street by using a long crane known as a gantry to lift and thread together 35-ton pre-cast concrete segments.  

The time-lapse footage shows crews using the massive crane to lift and suspend the segments while they are connected with heavy-gauge steel cables and epoxy. Thirteen segments make up a span of trackway, and 1,166 segments are being cast for the job. Around 20 to 30 segments are cast each week in Enumclaw, loaded onto trucks and transported to the construction site. Sound Transit and contractor PCL Construction used precast segments to build the elevated trackway between Seattle and the airport.  

Starting this evening, work on the guideway will shift from day to evening as the crane crosses over South 200th Street. Nighttime construction will take place from 7 p.m. to 6 a.m. for the next two weeks.  

Service to the future Angle Lake Station begins in 2016. The project is among the 34 miles of light rail extensions that Sound Transit is on track to complete by 2023. In early 2016 the agency is also set to open the University Link light rail extension between downtown Seattle and the University of Washington, six to nine months early and more than $100 million under budget.  

Transit will play an ever more critical role in the region's transportation system as our population climbs more than 30 percent by 2040 according to Puget Sound Regional Council projections. As traffic worsens, light rail will provide new, congestion-free capacity in some of the region's most congested travel corridors, benefitting riders and drivers alike. Sound Transit is working closely with local transit agencies and the state on strategies for keeping the region's people and economy moving.  

On June 13 the agency kicked public involvement options in preparation for updating the Long-Range Plan that will shape ballot measures for building further expansions after voter-approved projects are complete. Information on upcoming hearings, comment options and an online survey following the release of a Draft Supplemental Environmental Impact Statement is available at   

The Angle Lake Station will include a 1,050-space parking garage and public plaza, roadway, bicycle and pedestrian improvements, passenger platforms with covered waiting areas, and secured bicycle storage. A transfer area for local and RapidRide bus connections, dedicated areas for passenger pickup and drop-off, vanpool parking, secured bicycle storage, and public art are also elements of the project.