Course.

Seattle’s Tunneling Machine Bertha Veers Off Course
Seattle’s Tunneling Machine Bertha Veers Off Course
SEATTLE (AP) — Recent surveys have found that Seattle's new highway tunnel is a few inches off course and digging has stopped until next week while more measurements are made. Seattle Tunnel Partners project manager Chris Dixon said Wednesday that surveys found the concrete tunnel rings being installed behind the tunnel machine known as Bertha varied "a couple inches" beyond a 6-inch tol