Ahead of Elon Musk’s August announcement about the particulars of the Hyperloop, Russell Brandon at the Verge guesses at what the technologist will reveal. An excerpt:

“The details Musk has already hinted at tell us a great deal about the project, and outline a number of the challenges he’s likely to face. Based on simple math, we know it will have to travel an average of more than 600 mph. And it will have to do so almost frictionlessly, allowing for the low-power travel Musk envisions. It’s a big promise, and one that would have major consequences for the transportation industry and for society at large. For the technically minded, it raises the obvious question: how in the world is this thing going to work?

So far, the closest we’ve got is Japan’s superconducting maglev train — best known as the ‘bullet train.’ Its official top speed is 361mph, although it usually travels closer to 300 mph. Jim Powell, co-inventor of the bullet train and current director of Maglev 2000, thinks that’s as fast as open-air rail lines will ever go. ‘Air drag becomes too much of a problem after 300 mph, just from a power point of view,’ Powell says. ‘And then that air drag starts to generate noise. You wouldn’t want an airplane flying past your house at 600 mph.'”