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Big downtown Seattle tunneling project begins

AP News

SEATTLE, Wash. – After years of planning, the world’s largest tunneling machine has started drilling a new route for Highway 99 under downtown Seattle buildings.

The Washington Transportation Department says the tunnel will pass under about 200 buildings, but officials don’t expect any serious problems from the machine they call Bertha.

Digging began Tuesday afternoon.

Transportation officials even set Bertha up with her own Twitter account to provide updates.

The 326-foot-long, 7,000-pound machine will leave a tunnel nearly 58 feet in diameter.

The tunneling machine is part of the $3.1 billion project to replace the aging, earthquake-vulnerable Alaskan Way Viaduct, the double-deck highway along the downtown Seattle waterfront.

It will take about 14 months to complete a nearly 2-mile tunnel.