"Almost a year after Elon Musk, chief executive of Tesla Motors (TSLA) and SpaceX, first floated the idea of a superfast mode of transportation, he has finally revealed the details: a solar-powered, city-to-city elevated transit system that could take passengers and cars from Los Angeles to San Francisco in 30 minutes," reports Ashlee Vance. "In typical Musk fashion, the Hyperloop, as he calls it, immediately poses a challenge to the status quo—in this case, California’s $70 billion high-speed train that has been knocked by Musk and others as too expensive, too slow, and too impractical."
"In Musk’s vision, the Hyperloop would transport people via aluminum pods enclosed inside of steel tubes," she explains. "He describes the design as looking like a shotgun with the tubes running side by side for most of the journey and closing the loop at either end. These tubes would be mounted on columns 50 to 100 yards apart, and the pods inside would travel up to 800 miles per hour."
Though Musk claims his transportation system will travel four times as fast as California’s proposed high-speed train at one-10th the cost to build, Brad Plumer suspects it would cost a great deal more (even if the technology was proven). Writing in The Washington Post, Plumer notes that political pressures, design tweaks, and high land costs have driven up estimates for California's high-speed rail. "Early cost estimates for big new transportation projects are almost always wrong — and, at least if history is anything to go by, that’s not something that better technology will necessarily solve."
Respected transportation journalist Yonah Freemark tweeted a more succinct impression of the idea:
The Hyperloop concept is ridiculous. Let me just leave it there
— Yonah Freemark (@yfreemark) August 12, 2013
UPDATE: For a more thorough takedown, check out James Sinclair's post on the Stop and Move blog.