Last year at an event in Los Angeles, Tesla CEO Elon Musk revealed he'd come up with the idea for an entirely new form of transportation. He called it the Hyperloop, and here's how he described it:
...How would you like something that can never crash, is immune to weather, goes 3 or 4 times faster than the bullet train... it goes an average speed of twice what an aircraft would do. You would go from downtown LA to downtown San Francisco in under 30 minutes. It would cost you much less than an air ticket than any other mode of transport. I think we could actually make it self-powering if you put solar panels on it, you generate more power than you would consume in the system. There's a way to store the power so it would run 24/7 without using batteries. Yes, this is possible, absolutely.
Naturally this got people's curiosity up, and at this week's AllThingsD conference he was asked about it again. Not wanting to divert attention from Tesla, he briefly allowed that the Hyperloop would be a "cross between a Concorde, a railgun and an air hockey table."
This sounds a lot like the futuristic ET3, or Evacuated Tube Transport Technology, we wrote up last year (pictured directly below and up top).
But in their quest to figure out what Musk might be imagining, Business Insider has looked not to the future, but to the past. They dug up a Rand Corporation research paper written way back in 1972, where physicist R.M. Salter described a VHST (Very High Speed Transit System), which sounds like the ET3 but underground:
The VHST would be a vacuum sealed tube buried underground that would zip across the country... "The VHST's 'tubecraft' ride on, and are driven by, electromagnetic waves...."
[It] would be highly efficient. Unlike a plane, "it does not have to squander unrecoverable energy climbing to high altitudes." The VHST would accelerate to its maximum speed, then coast for a short while, then decelerate, says Salter. It would use all its kinetic energy to accelerate, and that power would be returned when it decelerates through energy regeneration.
In 1972, the Rand Corporation said it had already examined speeds of 14,000 miles per hour. At that speed, it would take 21 minutes to go from Los Angeles to New York City. According to Salter's research, a coast to coast VHST trip would happen faster than it takes a plane going coast to coast to get to its peak altitude.
The VHST would have to be underground. Digging the tunnels would be the biggest problem with creating the VHST. It would require political agreement and high costs to dig the actual tunnels. (90% of the cost would be building tunnels.) There are a lot of benefits to a tunnel, though: "protection against sabotage, right of way costs, surface congestion, grade separation problems, and noise pollution go away."
Salter's VHST paper can be freely viewed or downloaded here.