The world’s largest tunneling machine started grinding into the soil beneath downtown Seattle Tuesday afternoon. The machine known as Bertha is digging a 58-foot-wide tunnel to replace the Alaskan Way Viaduct.
Bertha is here. The world’s largest tunnel boring machine arrived in Seattle Tuesday after being shipped from Japan. It’s expected to reach land sometime this week. After that, in a few months, it will get to work drilling the tunnel that will replace the Alaskan Way Viaduct.