Alex Davies, for Wired:

They’re serious about this, too. It’s not a proof of concept, or a scale model. It’s the real deal. “It’s not a test track,” CEO Dirk Ahlborn says, even if five miles is well short of the 400-mile stretch of tubes Musk envisions carrying people between northern and southern California in half an hour. Anyone can buy a ticket and climb aboard, but they won’t see anything approaching 800 mph. Getting up to that mark requires about 100 miles of track, Ahlborn says, and “speed is not really what we want to test here.”