Concrete Tunnel Lining Pieces

Tunnel-boring machines burrowing their way among Seattle’s downtown, Capitol Hill and the University District are nearing the ends of their journeys.

In a few days, the machine digging Sound Transit’s southbound light-rail tunnel from the University of Washington will emerge at the Capitol Hill station.

A second machine, digging a parallel tunnel, will surface about a month later. The connection to downtown Seattle was completed in June 2012.

That’s cause for celebration in Seattle, but it means the end of the line for workers at a Tacoma concrete-casting plant created with $36 million in Sound Transit tunnel contracts.