Sadly, none of the stuff I've seen on Hyperloop addresses the civil engineering problems brought up by Alon Levy and others (https://pedestrianobservations.wordpress.com/2013/08/13/loop...). In short:

- The Hyperloop paper doesn't mention how trains would cross San Francisco Bay, or include a cost estimate for doing so. A new bridge? A new tunnel? Both would add greatly to the $6 billion cost estimate.

- That $6 billion estimate also assumes that elevated concrete pylons can be built for much cheaper than any other project, with no mention of how.

- The proposed track doesn't go to downtown LA; it ends at Sylmar, which is still ~25 miles from downtown and even further from most of the LA area. A 30 minute ride becomes much less exciting when it takes another hour or more to reach your real destination.

- With the proposed 30-second headway, the system's capacity is only about 25% of a high-speed rail line, and 30 seconds still violates the crap out of typical safety standards (you can't run trains too close together without risking a collision if you can't brake quickly enough).

- There are no intermediate stations; this is obviously a problem for the Central Valley, but it makes life inconvenient for plenty of other people too. Eg. someone in San Jose (pop. ~1 million, greater than SF's) would need to spend an extra hour or more getting to San Francisco vs. a station in San Jose itself.