> "Tubes located on pylons would limit access to the critical elements of the system." is meant to mean in §4.5.6 I'd be grateful...

You don't have to worry about cows wandering into oncoming vehicles like you do with cars and trains. It's also harder for non-determined people with malicious intent to interfere with operations.

A determined attacker can, of course, scale pylons. But you don't have to worry about stuff like kids lobbing bricks from overpasses, or people pushing others onto subway tracks.

Thanks–I think it was the fact that the pylons could presumably be scaled that was making the sentence difficult to parse (I wasn't sure how they were meant to prevent access). That, and that the pylons themselves are also presumably "critical elements" of the system.

the pylon could be the target to disrupt the operation

Yes, but so could tracks on any high-speed rail, and in that case with considerably greater ease. In this case, the actual railway is sealed off from all but the most determined external forces, who would be able to do just as much damage to a conventional train.

Indeed, I started getting giddy when he was discussing how to get the best power factor from the stator of the linear induction motor. It's obvious there's been a lot of thought put into this.

On the other hand even with a recommendation to use something similar to TSA doing something similar to airport security, his response plan to a terrorist attac--, er, a "human related incident" is basically to say that the system will have redundant power and vacuum pumps.

I suppose this isn't his area of expertise and so it's better to say little, but this is the kind of thing people are going to worry about before they board a small tube hurtling at 700 mph while 100 feet above the ground.

For instance, does a HRI impact his plan for rapidly handling luggage pods at all? Just one thing to think about...

He does mention luggage would be 1) handled by hyperloop employees 2) removed from the pod all at once to be handled at a different time. Probably more like these pods, which are mostly "blast resistant" http://www.freepatentsonline.com/6918501.html

The big benefit of being "not a plane" is that your emergency measures can be built around that concept. There's also a big benefit to only moving 30 people at once - terrorism looks for mass casualties or mass hostages. Blowing up a hyperloop is basically like bombing a bus - no one really bothers to try.

The big benefit of hyperloops over planes would all depend on how quickly you could brake those pods and re-pressurize the tube to let people escape. Because that's something you definitely can't do on a plane and it governs most of our thinking about them - if anything happens, you're possibly over an hour from being able to land anywhere and no one is able to get off quickly.

> Blowing up a hyperloop is basically like bombing a bus - no one really bothers to try.

Oh, bus-bombing happens; mostly in the middle-east, but it did happen in London once. You can google it.

I also expect that an explosion inside a depressurised pipe would shut the whole thing down in a way that an explosion above a road surface would not.

I'm really impressed to see the entire thing out in the public. They showed the designs, proposed routes, stress analysis, cost analysis... It's quire clear that this isn't just some "Hey I thought of an idea", they really put a lot of work into this.

I was worried this was going to be some pie-in-the-sky idea that was nebulous on a lot of basic details with quite a bit of "we can figure that out later".

> I was worried this was going to be some pie-in-the-sky idea

Sure, they put a lot of theoretical analysis into it, but its still pretty pie-in-the-sky. From the last page, note that

  The authors recognize the need for additional work,   
  including but not limited to:
    1. More expansion on the control mechanism for 
       Hyperloop capsules, including attitude thruster or 
       control moment gyros.
    2. Detailed station designs with loading and unloading 
       of both passenger and passenger plus vehicle 
       versions of the Hyperloop capsules.
    3. Trades comparing the costs and benefits of 
       Hyperloop with more conventional magnetic 
       levitation systems.
    4. Sub-scale testing based on a further optimized  
       design to demonstrate the physics of Hyperloop.

It's not a current competitor to high-speed rail, its more in the position that high-speed rail was in in the 1930s.

American high speed rail was more advanced in the 1930s than it is today. The Zephyr diesel passenger engine was faster than Amtrak's Acela speeds today.

I believe it means that the electrical components are not accessible from the ground where they might be vulnerable to vandals or animals.