A week ago, Seattle’s SR 99 tunnelling machine Bertha stopped near South King Street for scheduled maintenance. Crews have been thoroughly testing various systems and examining hoses and belts after 131 m of tunneling and 58 rings completed. The contractor Seattle Tunnel Partners decided to change 24 disc cutters for new rectangular teeth better suited for the glacial soils ahead. Disc cutters were needed to cut through the much harder grout-injected soils along the early part of the tunnel route. For tunnelbuilder archive click here and us/69. Visit www.AlaskanWayViaduct.org and www.wsdot.wa.gov. 45/13.