NEW YORK ( TheStreet) -- Some 30 years ago, Donald Fagen wrote a song called I.G.Y. about a great future then receding into the past: "On that train all graphite and glitter," he wrote. "Undersea by rail. Ninety minutes from New York to Paris." The conceit behind the song was that, in the past, specifically in the International Geophysical Year of 1957-1958, people trusted science, engineering and the people behind them to make a better world. Sputnik was launched during the I.G.Y. The Van Allen belts were discovered and plate tectonics were confirmed. So Elon Musk's concept of a Hyperloop, an air-powered tube whisking people and cars between Los Angeles and San Francisco in just 90 minutes, has a taste of science-fiction nostalgia about it, like the movie "Apollo 13." It wouldn't go undersea, but it would have rails. The concept is of a tube circling back-and-forth between stations, with very low air pressure, creating a low-friction suspension system that would shoot cars around like an air hockey puck, at speeds up to 700 miles per hour. Splits in the tube would allow construction of multiple stations along the way. The loop would cost $6 billion to $10 billion to build, Musk estimates, depending on whether you want to put cars inside it. This sounds expensive, until you realize high-speed train systems are being proposed between those cities right now that cost $70 billion and more, but don't go half as fast. Musk envisions the first Hyperloop system being built on pylons over Interstate 5, eliminating the cost of land, with solar panels on top of the loop being used to power the system. A Hyperloop "car" would have a compressor fan and motor in front, passengers and even vehicles in the center, and a large battery in the back. The fan would suck in air from in front of it, along the tube, and each car would cost just $500,000 to build, including the interior furnishings. There would be an emergency brake and each pod would be five miles away from its neighbor.