berthasr99-1sd1b3o

Japanese crews in 2013 assemble “Bertha,” the tunnel-boring machine that is being used as part of a massive infrastructure project in Seattle.

Japanese crews in 2013 assemble “Bertha,” the tunnel-boring machine that is being used as part of a massive infrastructure project in Seattle. Credit: Courtesy / Washington State Department of Transportation

Japanese crews in 2013 assemble “Bertha,” the tunnel-boring machine that is being used as part of a massive infrastructure project in Seattle.