Today Elon Musk has detailed plans of his Hyperloop that would get passengers to San Francisco to Los Angeles in under 30 minutes in almiumium pods that travel 800 miles per hour in huge steel tubes. The pods will be spaced five miles apart for safety, and a total of 70 could could operate at the same time.
The Hyperloop system would use a low air pressure environment that is easily maintained with regular compressors. It would also implement an electric compressor fan on the nose of each pod that would transfer high pressure air from the front to the rear of itself. The compressor fan would also provide an air bearing around the pod to keep it in the middle of the tube. Power would come from an external electric motors positioned 70 miles apart.
You can read more about the Hyperloop at spacex.com/hyperloop