World's Largest Tunneling Machine Ready for Repair

The world’s largest tunneling machine, known as Bertha, is now in position for repairs. The machine, which has been digging a new Alaskan Way Viaduct tunnel beneath downtown Seattle, was damaged at the end of 2013 while digging.

The machine has been moving into an access pit since February 17, making it fully into the pit on March 3. Bertha will now be taken apart and removed with a large crane so it can be repaired.

This time-lapse video posted on March 4 shows Bertha tunneling into the access pit. Credit: YouTube/Washington State Department of Transportation