Tunnelling starts on Seattle light rail line

Local and state officials christened two Herrenknecht TBMs at the University of Washington in Seattle on Monday as they begin their drives for the University Link light rail extension.

Seattle Transit’s USD 2bn project will connect the university with the city’s downtown via a 3.15-mile (5km) twin bore tunnels.

A joint venture of Traylor/Frontier-Kemper is using two Herrenknecht TBMs, each doing an 11,300ft (3.4km) drive from the UW station to the Capitol Hill station.

The JCM U-Link joint venture of Jay Dee/Coluccio/Michels is using one Hitachi-Zosen machine for the tunnels between Capitol Hill Station and Pine Street Stub Tunnel, a distance of approximately 1.15 miles (1.85km).

Excavation rates of 44ft to 50ft per day are expected on average.