(Map showing the zone where the tunneling machine is now, from WSDOT’s update page)

Among those taking time off for the holidays, the Highway 99 tunneling-machine crew. Here’s the last update of the year from WSDOT, with a bit more than one-fourth of the way to go on the tunnel route:

Seattle Tunnel Partners crews built their final concrete tunnel ring of the year on Tuesday before stopping for the holidays. The remaining days of 2016 will include a break for crews, followed by scheduled maintenance on Bertha, the SR 99 tunneling the machine.

In the year since STP restarted tunneling, Bertha has traveled approximately 5,700 feet and built almost 900 rings. Along the way, crews continued to control the ground as they mined beneath streets and structures, including the Alaskan Way Viaduct.

When mining resumes early in the new year, Bertha will be less than 2,500 feet from the pit near Seattle Center where she’ll emerge at the end of her journey. STP will continue to inspect and perform maintenance on the machine as needed.

Bertha’s cutterhead is located approximately 160 feet below Third Avenue between Blanchard and Bell streets. Progress updates are posted on Mondays and Thursdays at our Follow Bertha page. You can also follow Bertha on Twitter @BerthaDigsSR99.

Happy holidays from the Alaskan Way Viaduct Replacement Program. We’ll see you in 2017.

Current estimate is for the tunnel to open in early 2019. That’ll be almost a decade after the waterfront ceremony formalizing the plan; at that time, the hope was for a 2015 opening.