He doesn't properly address thermal expansion of the entire system. A long straight steel tube from SF to LA will expand a total of 300 meters over a 40C temperature change. Where does it go?
How does rail address this?
Hyperloop Alpha [pdf]
121–130 of 202 posts
Re: Hyperloop Alpha [pdf]
#122So what happened to section 5? Is that redacted by the NSA?
Re: Hyperloop Alpha [pdf]
#123Earlier quoted context omitted.
The bar to malice is important to consider. If the bar is "high explosives or shaped charges", then you are probably okay. If the bar is "a redneck who is bored with shooting stop-signs", then that might be a problem.
Bored people don't shoot guns at trains today. Why would they start?
Because there's no possibility that shooting at a train would result in a fireball a thousand yards high, whereas...
Re: Hyperloop Alpha [pdf]
#124How would you rescue when pod breaks down mid tube?
Re: Hyperloop Alpha [pdf]
#125Earlier quoted context omitted.
The bar to malice is important to consider. If the bar is "high explosives or shaped charges", then you are probably okay. If the bar is "a redneck who is bored with shooting stop-signs", then that might be a problem.
Bored people don't shoot guns at trains today. Why would they start?
Because the tube isn't a train?
Re: Hyperloop Alpha [pdf]
#126Location is a primary reason why Musk can claim Hyperloop will be cheaper than high speed rail. As the paper correctly points out, right-of-way acquisition is very expensive. Bypassing major population centers is an easy way out of using eminent domain or expensive tunneling to build the system. The HSR project is required by Proposition 1A to pass through several population centers in the state and have a couple doz…
For example, the "San Francisco" station appears to be located in the East Bay and the "Los Angeles" station is closer to Burbank. This is quite significant from an urban planning perspective as it means that short haul transit or car trips have to be accommodated for a majority of those people who want to use the system. It also adds to the total travel time needed to get from door to door for a greater number of people than does HSR.
I'm not an urban planner but it seems to me that accommodating one station in each city's boondocks might actually be easier than accommodating transit to several stations in the most central areas. San Leandro has a lot more room to build than SF and a lot of people will be coming to the SF HSR station if it's built there (even with a San Jose station).
Re: Hyperloop Alpha [pdf]
#127Cool concept, but a 500 mile bridge? Elevated transportation routes are expensive [1,2,3]. The utopian dreams tend to give way to an ugly reality [4,5]. The $1 billion budget for land and rights of way also seems wildly optimistic for razing a path through multiple heavily populated metropolitan areas with astronomical real estate prices. And let's not underestimate the tenacity and ingenuity of a determined oppositi…
In Singapore all short haul trains (called MRT) are either underground or on Pylons. Seems to work out well enough there.
Re: Hyperloop Alpha [pdf]
#128How would you rescue when pod breaks down mid tube?
The pods have something similar to landing gear for use at speeds less than 100 mph. Still, what happens to pods that are sandwiched between two malfunctioning/mangled pods? I think they should have contingencies where sections of tubes may be excised safely.
Re: Hyperloop Alpha [pdf]
#129Re: Hyperloop Alpha [pdf]
#130I worry that the necessary straightness of the tube will be difficult to achieve. The pads float 0.5 to 1.3 mm from the inside of the tube, so deviations from straightness on that scale will cause the pads to crash. Any contact at 760 mph would probably damage the pad, plugging the air holes.
Isn't there some kind of inverse square law affecting the force between the walls and capsule? The closer you get to contact, the harder it pushes back?
It should be largely self-correcting.