If you can’t go around it, go under it. That is the basic premise of the Tesla founder’s Boring Company and its plans for an autonomous high-speed tunnel system, known as Loop, to tackle Los Angeles’ traffic woes.

After Elon Musk got stuck in traffic in December 2016, he tweeted saying it was “driving him nuts” and he was going to “build a tunnel boring machine and just start digging”. This is the watershed moment that lead to the birth of the Boring Company.

Largely financed by Musk himself (amongst criticism that he’s having to sell hats to fund the project), The Boring Company hopes to one day enable travel between New York and Washington DC in under 30 minutes. This terminus is a long way off though, and numerous technological and political obstacles will have to be overcome if the firm’s ambitious are to reach their end. The latter category shouldn’t be underestimated.

Their latest challenge is to obtain planning permission from Culver City. A staff report released by the Culver City manager’s office earlier this week revealed details of the firm’s plans.

“The Boring Company, has proposed a privately funded human transportation tunnel that would run underneath the Westside of Los Angeles. The proposed route is from Hawthorne to West LA,” the report reads. Permission would provide a crucial win for the planned six and a half mile proof-of-process tunnel.

This ‘human transportation tunnel’ would provide the infrastructure for Musk’s innovative Loop technology. This is not to be confused with Hyperloop, which involves human-bearing pods travelling through a vacuum, but is a significant stride in this direction.

Loop Skate concept
Concept drawing of a Loop skate

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The difference between Loop and Hyperloop

It was back in 2013 that Musk first latched on to the potential of Hyperloop. His whitepaper created great excitement in the industry, and after being assured of its feasibility by his advisors, President Obama stated pithily, “Let me know how I can help you”. However, the bridging technology to this is Loop.

Loop is a high-speed underground public transportation system that will carry passengers on autonomous electric skates travelling at 125-150 miles per hour. The aim is for skates (air casters) to be able to ferry up to 16 passengers or a single passenger vehicle.

Electric induction motors, like the one used in the Tesla Model S but rolled flat, can accelerate the skates to high subsonic velocity. Each skate would only need a boost roughly every 70 miles, keeping costs down.

Hyperloop is similar in that passengers would be transported through a tube in an autonomous, electricity-powered, pressurized capsule. The difference is that the use of a vacuum inside the tube eliminates air friction, allowing speeds of over 600 miles per hour.

While this concept sounds distinctly sci-fi, the idea first surfaced in 1909 when rocketry pioneer Robert Goddard proposed a vacuum train. Given the time required to reach these speeds and slow down again, Loop is much more suited to short distance travel.

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The Boring Company’s grand vision

The Culver City permit application is not the Boring Company’s first. In October 2017, they submitted plans to the City of Los Angeles for those sections of the tunnel that run beneath their jurisdiction. The city has yet to grant approval however, and there is some concern amongst councillors regarding the implications of allowing the private company to compete against existing transport providers.

There are encouraging signs when it comes to overcoming planning issues, though. The City of Hawthorne approved a subsurface easement agreement in August 2017 for The Boring Company to build a two mile long test tunnel, which is now under construction.

The Boring Company is also working with officials on a DC to Baltimore route (which could then be extended to New York). In a promising first step, the State of Maryland has granted permission for 10 miles of tunnels. Meanwhile, in Chicago, The Boring Company is competing to build a high-speed Loop connecting Chicago O’Hare Airport to downtown.

All hype and no loop?

Tunnels are traditionally extremely expensive to dig, sometimes costing as much as $1 billion per mile. For a Loop tunnel network to be viable, tunnelling costs would need to be 10 times cheaper.

The boring company has several ways of doing this. By placing vehicles on stabilised electric skates, the tunnel diameter can be reduced to under 14 feet. Halving the diameter would reduce tunnelling costs by three to four times.

Secondly, tunnel boring machines are incredibly slow. In fact, they’re 14 times slower than a snail, according to The Boring Company. They hope to produce machines that can go for longer, while reinforcing the tunnel at the same time – all with less human supervision. There is a pressing need to innovate technology that has been stagnant for decades.

Each station would consist of a bank of elevators. These can be as small as a parking space, so, unlike a subway, an unlimited number of stations can be built along the tunnel route.

The Boring Company's boring machine
The Boring Company’s boring machine (Credit: The Boring Company)

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The route to hyperloop?

Despite efforts in the past by Rand Corporation and ET3, and more recently, Tesla, SpaceX and Virgin Hyperloop One, a commercially viable Hyperloop remains a long way off. The challenge of drawing a hard or near hard vacuum in a tube, and then using electromagnetic suspension (maglev) to suspend transportation pods, is a mammoth technical undertaking.

“The problem with this approach is that it is incredibly hard to maintain a near vacuum in a room, let alone 700 miles (round trip) of large tubes with dozens of station gateways and thousands of pods entering and exiting every day,” says Musk in his whitepaper. “All it takes is one leaky seal or a small crack somewhere in the hundreds of miles of tube and the whole system stops working.”

When using a low-pressure system instead, a nose-mounted electric compressor fan, helps to overcome the Kantrowitz Limit and generates a cushion of air underneath the pod as it travels through the tube, providing a much more effective solution than wheels at high speeds.

Musk and his detractors are equally aware that there is still a great deal of design and proof of concept work to be done to bring Hyperloop from the drawing board to solid ground. This includes, more detail on the control mechanism for Hyperloop capsules, such as an attitude thruster or control moment gyros; detailed station designs with loading and unloading of passengers, and sub-scale testing to demonstrate the physics of Hyperloop. The technology’s advocates will also need to prove the benefits of Hyperloop over more conventional magnetic levitation system.

Visionaries and innovators have always been mocked by those who doubt the viability or realism behind their plans. Yet, regardless of whether Musk’s hyperloop dream finds form, while the doubters idly scoff, he is busy doing. And that’s just the kind of self-belief needed to introduce the first new mode of transport since the airplane.