Tesla CEO Elon Musk is a man of many and advanced interests, and his latest notion--the Hyperloop rapid transit system revealed as a concept yesterday--fits into his vision of a very different future.

In a nutshell, the Hyperloop is a system in which people board pods inside an elevated metal tube on pillars that carry them from San Francisco to Los Angeles in about half an hour, at speeds up to 800 miles per hour.

It was Musk's reaction to the proposed California High-Speed Rail project that is to connect the same two cities, and ultimately run from San Diego to Sacramento, that got him thinking about a Hyperloop concept.

Expensive, slow 'high-speed' rail

That high-speed rail is a ground-based system that uses conventional fast-train technology. It's projected to cost $70 billion to complete by 2029, with the first section slated to begin construction within the year.

If the history of large infrastructure projects holds true, the final cost might exceed $100 billion.

Musk called the proposed California high-speed rail system "both one of the most expensive per mile and one of the slowest in the world."

His Hyperloop system, he says, could be built for a tiny fraction of that cost--$6 billion to $10 billion, he suggests.

In his preface, Musk wonders whether such a system could become "a fifth mode after planes, trains, cars and boats," cheaper than airplane travel for city pairs up to 900 miles (1500 km) 500 miles apart.

'Revenge of the Electric Car' premiere: Tesla Motors CEO Elon Musk on red carpet

'Revenge of the Electric Car' premiere: Tesla Motors CEO Elon Musk on red carpet

Freeway rights-of-way

For one thing, riding in a dedicated tube on pylons 50 to 100 yards apart, it could run along the right-of-way of existing freeways, both speeding construction and avoiding land acquisition.

That model has already been used, successfully, to build New York City's AirTrain from the Jamaica train station in Queens to John F. Kennedy International Airport.

Its track runs in a trough constructed out of pre-cast concrete sections on concrete columns running down the narrow median of the crowded Van Wyck Expressway along the same route.

No plans to pursue

Much discussion of and debate over on the Hyperloop concept will now ensue, but Musk has no plans to pursue it at the moment.

He's putting the concept (designed the "Alpha" version) out there for others to critique, though if nothing's happened with it in several years, he said, he might return to it after he's a bit less busy.

“I wish I had not mentioned it,” he noted yesterday in a Business Week interview. “I still have to run SpaceX and Tesla, and it’s f*cking hard.”

Concept drawings for Elon Musk’s 800-mph Hyperloop

Concept drawings for Elon Musk’s 800-mph Hyperloop

What's it like to ride in?

But one concern that arose for us yesterday is something we haven't yet seen addressed: What would the user experience be?

In the concept drawings and descriptions, two variants are proposed at two different scales.

The smaller of the two would have pods containing single seats within a narrow car something like a very narrow rail car.

The side of that flips up, very much like the "falcon doors" on the concept for the 2015 Tesla Model X electric crossover utilty vehicle.

Its entire nose is a large electric fan that would take in air at high speed to propel the vehicle-think of it roughly as a sort of large jet engine--as well as suspending it just above the surface of the tube on a cushion of air.

Concept drawings for Elon Musk’s 800-mph Hyperloop

Concept drawings for Elon Musk’s 800-mph Hyperloop

A larger-scale version would allow people to drive inside the Hyperloop pods in their vehicles, presumably remaining there for the duration of the trip.

Riding comfort

But as reader Brian Santo noted yesterday,

A pod inside a closed tube? A pod. Inside. A closed. Tube. My claustrophobia is mild, but I do not think I, for one, would be able to make it from LA even to Van Nuys without losing it. That's if I didn't get motion-sick first. And of course, both simultaneously might be possible. Will we be sharing these pods?

Motion sickness is prevented, the plan says, because the pods would bank against the tube like an airplane on turns--and would not be subject to turbulence.

It would have, Musk said, less lateral acceleration than riding on any big-city subway--and that's the motion that tends to make people sick. The ride, he said, would "feel supersmooth" and be entirely pleasant.

Fair enough.

Lack of windows

But then there's the issue of riding inside a small space without being able to see out.

The drawings appear to show a solid aluminum tube to hold the pods, and it's easy to surmise that adding windows both to the pods and the tubes so passengers could see out would add complexity, cost, and structural vulnerability.

That's be a question of execution, of course, but the nearest comparison we can think of is the Le Shuttle train service under the English Channel from Folkestone in England to Calais in France.

There, cars, trucks, campers, and even buses drive onto specially constructed train cars for the journey. Drivers and passengers can stay in their cars, but they can also get out and walk along gangways to bathrooms--giving them a bit of elbow room.

It's not at all clear whether any Hyperloop design might find that to be a usability requirement--or would provide bathrooms in the people-only pods.

The ride would be smooth, and most likely there would be a monitor for programming--perhaps individual seatback monitors for each passenger. We'd assume there would also be broadband access.

So our question becomes: What's your reaction to the idea of spending half an hour in a small, windowless pod of, say, eight to 12 seats?

For more details on the concept, see Musk's posting on the Tesla Motors [NSDQ:TSLA] website. His blog post also links to the full 57-page concept document.

Leave us your thoughts--on that question, and on the Hyperloop concept in general--in the Comments below


Follow GreenCarReports on Facebook, Twitter, and Google+.