Under Seattle is Quite the Bore

LA Times:

But it was "Bertha," a 7,000-ton, 326-foot-long and 57-foot-tall drilling device, which is playing a central role in a project that will redefine Seattle's waterfront — and perhaps the city itself.
The drill has embarked on a project to bore a 2-mile tunnel beneath the city's downtown and replace an unsightly, 60-year-old double-decker highway that courses along the waterfront, separating the high-rises of downtown from the majestic panorama of the Puget Sound.  The $3-billion project — one of largest public works undertakings in the country — began after a decade of contentious back-and-forth, scores of proposed ideas and a few failed ballots. Since the drilling began in late July, much of the attention has been directed at Bertha, named for the city's first and only female mayor and described by experts as being as sophisticated as it is gargantuan.
After the highway known as the Alaskan Way Viaduct was damaged in the 2001 Nisqually earthquake, officials decided to replace it, beginning a protracted debate that reached beyond a question of transportation to something larger: a vision for the future of Seattle. As MacDonald put it, the decision would have "50, 100 years' impact on what the waterfront of Seattle will look like."
In all, the list of more than 90 options was whittled down to three: replacing the three-lane Alaskan Way Viaduct with a larger roadway; digging a tunnel from above ground — a so-called cut-and-cover, such as Boston's Big Dig mega-project; or simply putting in a surface street, which would force motorists from their cars and, advocates for this plan hoped, onto public transportation.
As those plans ended up being untenable, officials looked into boring technology, which had gone through significant advancement in recent years. The solution arrived, MacDonald said, like something out of a Greek play — it seemingly came out nowhere. "The machine became the deus ex machina," he said.
Bertha was assembled in the 80-foot-deep pit and will displace 850,000 cubic yards of soil for the double-level, two-lane tunnel running between 60 and 200 feet below the ground. The viaduct will be demolished and replaced with a surface street and public park space.

Cool as hell. There's a video at the link, but I couldn't get the autoplay turned off.