Musk mentions RAND's previous work in his paper, but he thinks the vacuum requirement is impractical: https://www.tesla.com/sites/default/files/blog_images/hype

Musk mentions RAND's previous work in his paper, but he thinks the vacuum requirement is impractical: https://www.tesla.com/sites/default/files/blog_images/hyperloop-alpha.pdf https://www.tesla.com/sites/default/files/blog_images/hyperl... > Is there truly a new mode of transport – a fifth mode after planes, trains, cars and boats – that meets those criteria and is practical to implement? Many ideas for a system with most of those properties have been proposed and should be acknowledged, reaching as far back as Robert Goddard’s to proposals in recent decades by the Rand Corporation and ET3. [...] > Another extreme is the approach, advocated by Rand and ET3, of drawing a hard or near hard vacuum in the tube and then using an electromagnetic suspension. The problem with this approach is that it is incredibly hard to maintain a near vacuum in a room, let alone 700 miles (round trip) of large tube with dozens of station gateways and thousands of pods entering and exiting every day. All it takes is one leaky seal or a small crack somewhere in the hundreds of miles of tube and the whole system stops working. (ET3 is these folks: https://en.wikipedia.org/wiki/ET3_Global_Alliance https://en.wikipedia.org/wiki/ET3_Global_Alliance)