Follow Bertha

Following Bertha, the SR 99 Tunneling Machine

View from the construction camera looking south toward the SR 99 tunneling machine launch pit. Additional views are available on the construction cameras page.

Preparing for Bertha’s summer launch

After a 5,000-mile journey from Japan and 10 days of unloading, Bertha, the world’s largest-diameter tunneling machine, is officially on Seattle soil. Her 41 pieces are now arrayed near the pit to the west of Seattle’s stadiums (pdf 485 kb) where she’ll begin digging a two-mile-long tunnel beneath downtown this summer.

Over the next few months, crews will be hard at work preparing Bertha for her dig. That includes lowering her pieces into the launch pit for assembly and conducting a series of rigorous tests to ensure she’s working properly before tunneling begins.

You can track all of the action on our construction cameras. And don’t forget Bertha is on Twitter. Followers of @BerthaDigsSR99 will continue to get regular updates straight from Bertha herself as she prepares to start digging beneath Seattle.

Other resources

  • Go to Milepost 31 in Pioneer Square to see a motorized, 10-foot-long model of Bertha.
  • Our Flickr site has photos of crews building the machine Japan and crews in Seattle preparing for the machine’s arrival.
  • Check out two new videos about the SR 99 tunneling machine, below.

 

Tunneling machine animation (2013). Courtesy of Hitachi Zosen Corp., this animation shows how the world’s largest tunneling machine works. View on YouTube or download WMV file.
Building a new State Route 99 through Seattle (2013). Bertha, the SR 99 tunneling machine, has arrived in Seattle. This short video provides an overview of Bertha’s journey and the work WSDOT is doing to replace the SR 99 Alaskan Way Viaduct. View on YouTube or download WMV file.

Bertha press releases

 

 

Offloading the machine's cutterhead at Terminal 46.

Offloading the machine's cutterhead at Terminal 46.

 

The SR 99 tunneling machine will be assembled in this 400-foot-long launch pit.

The SR 99 tunneling machine will be assembled in this 400-foot-long launch pit.