What impresses me most about TBC is how fast they were able to dig a tunnel.<p>I'm in Seattle, and Bertha was digging for about five years. And it's been an incredibly expensive effort, with lots of setbacks and budget overages.<p>Granted, it's digging a much larger tunnel, and the ground it's digging though is probably different than a stretch of land in LA.<p>But TBC was whipped up what... a bit more than one year ago? And from scratch, they've already completed a 2 mile tunnel, and I'd be surprised if it was at a cost-per-mile <i>anywhere</i> near what Bertha ran.