• 05.09.16

A Drone Goes Inside Seattle’s Enormous New Tunnel

For a sense of scale, imagine a gnat flying behind a sandworm from Dune.

Bertha, as she is affectionately known, is the 57-foot-tall, 325-foot-long tunnel-boring machine that is currently carving out a $3.1 billion subterranean highway underneath Seattle. There’s no more awesome example of machinery in all of North America, but the only way to really get a sense of Bertha’s sheer scale is by watching this video. Shot by a drone “working” for the Washington State Department of Transportation, the video shows that Bertha is more than just a giant drill. It’s a giant drill with a fortress on its back.


Right now, Bertha has dug over 1,500 feet of the SR-99 tunnel, which will eventually be a two-story underground highway. Essentially, the way Bertha works is by using a rotating cutterhead to carve out earth in front of it, then feeding this earth on a long conveyor belt back to the surface. Behind the cutterhead, there are enormous structural rings, which help support the tunnel’s weight until they can be reinforced with curved concrete segments. After the structural rings are laid down, Bertha uses hydraulics to lurch her enormous bulk forward a few feet at a time. Rinse and repeat.

If there’s a porn magazine dedicated to sexy machines, Bertha’s got to be the centerfold. Unfortunately, though, Bertha’s had a run of bad luck. She first started digging the 1.7-mile long SR-99 back in December 2013, when the cutterhead was damaged by a steel pipe, requiring a two year delay as workers tunneled down from the surface to lift Bertha’s bore out for repairs. She only resumed digging on December 22, 2015, roughly when the tunnel was originally meant to be completed. She has since been delayed a few more times, and is now projected to be finished boring by January, with the tunnel opening to the public in April 2018.

Of course, that all depends on everything going perfectly from now until January. Chances are, Bertha will be delayed again. Still, looking at a machine this beautiful, it’s hard to fault her for being slow. She’s got a lot of junk in the trunk, after all.