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Comment by ye | Hacker News Reader

Building the structure is the least of the Hyperloop's problem.

How about supporting near-vacuum on such a large scale?

How about dealing with earthquakes, erosion, landshifts, where even a small shift in a section of a tunnel would mean instant death for the travelers.

How about obtaining the land rights to build it between SF and LA?

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Pretty much all of which were addressed in the whitepaper. Any specific reasons why you believe the treatment in the whitepaper doesn't hold water?

Regarding ground changes, we can look to current bullet-train rail systems. Nobody has ever died on a bullet train in Japan due to earthquakes. I saw on a documentary that Japan feed seismic sensor data into train control centers where any dangerous seismic event would trigger automatic stopping of the trains.

I never said it's impossible, I think it's a much bigger problem than building a machine to build the tunnel walls.

How is it a bigger problem if it has already been solved today?

The original paper attempts to deal with all of these problems, pressure, safety, land rights, it's a very interesting read.

First of all, it hasn't been solved in the US, and not for these speeds, which are at least double of the fastest bullet train in the world.

No passenger has ever died on the Japanese Shinkansen, but a train was derailed during an earthquake. The safety of high-speed trains, both in Japan and elsewhere, also relies on safety during a derailment by keeping the train rigid and having steel cars. In contrast, it seems to me that a breach of the integrity of the hyperloop tube would probably be fatal. Also, the higher speed of a hyperloop makes automatic stopping take longer.

In all, the hyperloop as it's currently being presented is much more dangerous than high-speed rail during an earthquake, and this is a legitimate concern.

I don't think the hyperloop requires near vacuum. As far as I understad it is filled with moving air.

It does require a near vacuum. At high speed, the tiny amount of air in the tube gets compressed to the point where it plays a significant role in the dynamics of the train's motion. So, both are true.

According to their specs, it's 1/1000 of normal air pressure.

http://www.spacex.com/sites/spacex/files/hyperloop_alpha.pdf

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