How was the tunneling machine repaired?

Tags: sr99

Seattle Tunnel Partners built a 120-foot-deep pit in front of the machine. When the pit was complete, the machine tunneled forward into it. Crews then partially disassembled the machine and made repairs and enhancements. This narrated video (links to YouTube) explains the repair process in detail. The machine mined out of the pit in January 2016 and completed the SR 99 tunnel drive in April 2017.