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Bertha
A photo of the tunnel boring machine's cutter head.

Age: <1
Height: 57.5 feet
Weight: 7,000 tons
Length: 326 feet
Occupation: Tunneling specialist
Likes: Dirt, small boulders, perfectly formed concrete rings
Dislikes: Sunlight
Role models: Bertha Knight Landes, Marc Isambard Brunel, whoever invented the shovel
Twitter: @BerthaDigsSR99
View photos on Flickr

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Advisories/Updates

  • Lane reductions on one block of First Avenue in downtown Seattle week of Feb. 4

    Crews installing underground monitors along the State Route 99 tunnel route next week will reduce southbound First Avenue to one lane between Pine and Pike streets.

    Crews will also close street parking on both sides of First Avenue. Signs will direct drivers around the closures. The work will not affect access to parking lots, buildings or driveways.

    Travel impacts

    Monday, Feb. 4 – Friday, Feb. 8: Southbound First Avenue between Pine and Pike streets will be reduced to … more

Program Spotlight

  • Testing of the SR 99 tunneling machine continues in Japan

    Before a professional athlete joins a new team, he has to pass a physical.

    Same goes for Bertha, the world’s largest-diameter tunneling machine. She doesn’t play a sport, of course, but digging a two-mile-long tunnel beneath downtown Seattle requires just the right combination of speed, skill and body control – all hallmarks of a world-class athlete. Which is why Bertha’s manufacturer, Japanese firm Hitachi Zosen Corporation, is putting her through the wringer as … more