We've covered Elon Musk's proposed Hyperloop before, including some speculation on what kind of system he might propose. The mass transit concept unveiled today is similar, in some respects, to the evacuated vacuum tube first proposed by the Rand Corporation in 1972, but varies in a number of key areas. It doesn't rely on maintaining a full vacuum, but instead offers an atmosphere roughly 1/6 pressure found on Mars, or equivalent to cruising Earth at 150,000 feet.
As expected, the initial LA - SF proposed run would accelerate passengers to trans-sonic velocities, but they wouldn't do it using maglev. Instead, a linear induction motor is used to provide the necessary acceleration and deceleration, with a compressor mounted on the front of each passenger vehicle. The compressor is an important part of the system because it prevents the air in front of each pod from building up too much pressure, heat, and friction across the front of the craft. In order to travel inside a closed tube, the distance between the pod and the tube walls must be small enough to allow air pressure itself to act as a skid and balancing force.
Obviously we're covering the craft at an extremely high level. The major takeaways are this: Musk's Hyperloop wouldn't require a total vacuum (these are extremely difficult to maintain). It could be built in sections, following preexisting travel lanes, and wouldn't require much room. It's designed to sit on pylons, which means the need to clear land and secure property rights for a full installation, the way the proposed high-speed rail lines would do, is not an issue. It could be self-powered, with enough solar panels mounted on the Hyperloop's external body to power the linear induction motor inside.
Passenger capsule schematic
In the event of emergency, capsules inside the pod would contain sufficient emergency oxygen reserves to pressurize breathing masks for all the occupants. Capsules would also contain battery backups that could run the lights and provide radio contact with the end station. Because LA - SF transit from launch to walk-off is estimated at 30 minutes, the vast majority of emergencies could be best attended to by finishing the trip at the destination and notifying the authorities to stand by. In the event of a serious breach of the tube itself, the pods could deploy conventional wheels and make the trip by battery power.
The total cost of the Loop, according to Musk's estimate, is about $4.06 billion. That's a fraction of the estimated $68 billion to build Phase 1 of the California High-Speed Rail network. A version capable of transporting both passengers and vehicles could be built from roughly 25% more money, with cars capable of leaving up to every two minutes in both versions of the system.
Musk's interview with Bloomberg, with more details on the project
Will it get built? I'm inclined to think not, given that it took almost eight years for the California Rail project to get started and is still in the very early stages of construction (I'm not sure if track has been laid at this point, but some terminal construction has been done). Still, Musk's Hyperloop could fire the imagination of private developers that could conceivably help kickstart the project with personal funds.
Musk himself doesn't plan to lead the charge but clearly put a great deal of work into developing the system. Hopefully someone will put it to use.