Has Elon Musk Made a Tunnelling Breakthrough?

Earlier this week Elon Musk demonstrated a new transit system near SpaceX's headquarters, running Teslas through a tunnel dug by his Boring Company. From what I've read, most articles treated it as something of a joke, but they missed the key point. That tunnel, basic as it was, was dug at a cost that's at least an order of magnitude less than the tunnelling systems used by most major transit projects. Musk also claims that the Boring Company can dig turnnels at least ten times faster. 

I think the idea of running cars through tunnels, even if they are moving at 150 miles per hour, is silly, and it certainly won't do much to relieve traffic congestion. But if the Boring Company can scale their machines to the size needed to dig subway or railway tunnels, they might make it a lot easier to build public transit. 

As this article points out, subway tunnels in the US (and Canada, although the article doens't show any Canadian statistics), are expensive, somewhere between 500 million and 1 billion dollars a mile. Even allowing for the costs of adding the necessary infrastructure, Musks costs would appear to be somewhere under a tenth of that. 

Rail fans may be laughing or hanging their heads at Musk’s display, given the entrepreneur/inventor/CEO’s tendency to make big promises, as well as his commitment to displacing more proven, efficient modes of transit from conversation. But it’s hard to dismiss one key achievement of this project. Musk put a Tesla in a tunnel, and he did it for a potentially game-changing price: The demonstration tube cost $10 million a mile to dig, according to Musk.

That excludes costs of research, development, or equipment, the L.A. Times reported. Whether it factors in property acquisition or labor—which generally represents at least 30 to 40 percent of a project’s cost—isn’t clear. But even at $50 million per mile, it would still be a fraction of what comparable projects cost. If Musk’s company has built what many tunneling pros have long thought unachievable—a boring machine that does the job cheaper and faster than the stalwarts of civil engineering thought possible—that could be a boon for underground transit systems in the U.S., which often struggle to justify their enormous construction costs.

I should note that being tunnels aren't the only part of an underground transit system, as those living along the Eglinton Crosstown LRT line in Toronto are finding out. The tunnel machines finished their job a year ago, but the line won't open until 2020 or 2021, largely due to the time it takes to build the underground stations.