Mayor Rahm Emanuel considers himself as a visionary who transcends partisan politics to offer practical, forward-thinking solutions based on public-private partnerships. His latest idea is to farm out the old O'Hare express-train dream to Elon Musk's Boring Company, which claims to be able to radically reduce construction costs in order to make tunneling affordable, and in doing so make the project happen with no public money, in less than three years, and pay for itself at about $25 per ticket.
But are Musk's claims really correct? The evidence suggests otherwise.
How much does tunneling cost?
The impetus for the Boring Company is that subway tunneling in Los Angeles costs nearly a billion dollars per mile. This is high by international standards, and too high to justify extensive investment in Los Angeles given its low-density, auto-oriented character. The international range for tunneling is wide: at the high end, Second Avenue Subway in New York cost $2.7 billion per mile, and at the low end, Madrid and Seoul build subway tunnels for about $150 million per mile.
Such a wide chasm between the cheapest and most expensive tunnels can only come from a large number of interconnected causes. At the high end, it's the stations that cost the most money, amounting to three quarters of the cost of Second Avenue Subway, courtesy of expensive methods meant to minimize street disruption. Regional rail projects that build large underground train stations in city centers cost even more than subways: New York's East Side Access project, consisting of about a mile and a half of tunnel, a deep cavern beneath Midtown Manhattan, and some new surface rail connections, has blown up to cost $11 billion. In contrast, long nonstop segments, or connections between lines that do not involve new stations, can be quite cheap, including one tunnel in Barcelona built for about $70 million per mile, without any new stations. (The O'Hare-downtown tunnel would be approximately 15 miles, which at $70 million per mile would come out to $1.05 billion; a source told the Tribune that the Boring Company is estimating the project will cost less than one billion dollars.)
Unfortunately, Musk seems unaware of this range of costs. The Boring Company FAQ makes claims about how it plans to reduce the expense of tunnel construction. It focuses exclusively on tunnel boring, even though it is the cheapest and most streamlined component of underground construction (even East Side Access, by far the world's most expensive rail tunnel, is only about $350 million per mile for tunnel boring in Manhattan). It says,
The current standard for a one-lane tunnel is approximately 28 feet. By placing vehicles on a stabilized electric skate, the diameter can be reduced to less than 14 feet. Reducing the diameter in half reduces tunneling costs by 3-4 times.
This claim is contradicted in professional literature. Studies of particle accelerator tunnels as well as rail tunnels that look at different diameters find that reducing the diameter in half reduces costs by a factor of two and not three or four.
In fact, in cities at the forefront of cost reduction, the trend is toward bigger tunnels rather than smaller tunnels. Large-diameter highway tunnels permit putting multiple lanes in one bore, sometimes even on two levels. Large-diameter subway tunnels permit putting the train platform within the bore, saving the cost of mining stations in constrained city centers.
Within Chicago, the Loop is a more constrained city center than nearly any European central business district. With two deep tunnels for the Red and Blue Lines, and many skyscrapers with deep foundation, the most complex part of any new tunnel within the city is how to construct the Loop stations. Musk is planning on using the mothballed Loop station that was built the last time a Chicago mayor pushed for an O'Hare express train, but even that would likely require hundreds of millions to complete.
Can Musk deliver on his promises?
The Boring Company is Musk's second attempt at reinventing public transportation. The first one was Hyperloop, a paper he released in 2013, arguing that he could build a system that would be faster than California High-Speed Rail and cost one tenth as much, just $6 billion between Los Angeles and San Francisco. The paper was riddled with errors and Musk soon abandoned the idea of constructing this system himself.
Other engineers, believing Musk to be a visionary, took it upon themselves to make Hyperloop a reality. However, while designing the system in more detail, they quickly had to abandon Musk's outlandishly low cost estimates. Hyperloop One, designed by former managers from Musk's NASA contractor SpaceX, built a low-speed prototype, and is claiming construction costs two thirds as high as those of conventional high-speed rail. However, its proposed project within the UAE, connecting Dubai and Abu Dhabi, is said to cost $52 million per mile, about the same as a conventional high-speed rail line would over a route with similar characteristics (that is, mostly flat, unpopulated desert), and higher than many European high-speed lines. While Hyperloop appears feasible as a technology, Musk's promises of cutting construction costs by a factor are not so feasible.
Musk's biggest transportation project—Tesla Motors—is plagued with missed projections as well. The Model 3, which Tesla aimed to make a more affordable alternative to the luxury-priced Model S, has been subject to delays and production shortfalls. The Green Car Reports finds the car's quality “appalling.” Musk himself admitted that Tesla's attempt to automate production was a mistake, and said “humans are underrated”; nonetheless, the Boring Company FAQ maintains that automation of tunnel boring is the way forward.
Public transportation loses money nearly everywhere, but Musk's venture will need to either make money if he's to keep the mayor's no-public-money promise. That Tesla loses money, and that the rest of the auto industry is bypassing it with all-electric Toyotas, suggests that Musk is just not good enough as an engineering business manager to be trusted with new technology. If Chicago wishes to build an O'Hare express, it should use proven approaches and proven contractors.
But the city is looking for pizzazz rather than for good transit. The Blue Line already connects the Loop with the airport, so an express train would be the second connection. But O'Hare itself has 3.9 million annual entries on the L, a fraction of the O'Hare branch's 29 million. The decision to prioritize the O'Hare express train comes from the same place as the decision to contract Elon Musk to build it despite his lack of technical expertise or knowledge of the subject matter. City elites, including Mayor Emanuel, fly routinely and wish the trip to the airport were faster, but are not representative of the broad public. The same city elite that thinks an O'Hare-Loop connection is a high priority also thinks that businesspeople who are well-covered in the media are the best people to lead such a project.