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Hyperloop Alpha [pdf]

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Re: Hyperloop Alpha [pdf]

#151

Post by jhaglund »

fludlight wrote: post #115

Cool 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…

http://en.wikipedia.org/wiki/Overseas_Railroad

In 1905, they built 128 miles of railroad connecting the Florida keys. Since then, engineering has advanced significantly. Overland is still easier than overseas.

Re: Hyperloop Alpha [pdf]

#152

Post by justinpombrio »

jlgreco wrote: post #143
simonebrunozzi wrote: post #134

Earlier quoted context omitted.

Only 50-100? I would go as far as 200! :)

Well, I probably would too, but depending on the airline, that is nearing first class levels. Of course on many/most planes "first class" does not get you isolation from children... (certainly not for that low a price) but at least you get unlimited liquor and legroom. I'd be willing to pay more for a flight without children but I would want some unlimited liquor once I go over 200 or so. On this note, what would be…

Don't worry -- once the hyperloop is built and running and we still don't have a practical supersonic airliner, Musk will sigh and design one of those for us too.

Re: Hyperloop Alpha [pdf]

#153

Post by jlgreco »

count wrote: post #148
kingkawn wrote: post #123

Earlier quoted context omitted.

Because there's no possibility that shooting at a train would result in a fireball a thousand yards high, whereas...

How thick are propane tanker cars?

Back of the bar napkin calculation with Barlow's formula, assuming 200psi (about what bbq tanks are at iirc?), somewhere around half an inch.

Re: Hyperloop Alpha [pdf]

#154

Post by jlgreco »

justinpombrio wrote: post #152
jlgreco wrote: post #143

Earlier quoted context omitted.

Well, I probably would too, but depending on the airline, that is nearing first class levels. Of course on many/most planes "first class" does not get you isolation from children... (certainly not for that low a price) but at least you get unlimited liquor and legroom. I'd be willing to pay more for a flight without children but I would want some unlimited liquor once I go over 200 or so. On this note, what would be…

Don't worry -- once the hyperloop is built and running and we still don't have a practical supersonic airliner, Musk will sigh and design one of those for us too.

IIRC, he's actually talked about electric airliners a few times, though I'm not sure if those ideas were for supersonic electric airliners. I suspect not, but at the least it seems to be an industry he has thought about.

Re: Hyperloop Alpha [pdf]

#155

Post by tod222 »

eco wrote: post #121
tlb wrote: post #39

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?

Prior to the use of continuous welded rail there were gaps between each 39 foot section of rail.

Nowadays with welded rail, careful compliance with construction standards is required. Slow orders are issued during heat waves and frequent track inspections are conducted to look for potential or actual sun kinks.

A good summary of the issue can be found in the Heat Orders FAQ from Virginia Railway Express. [1]

[1] http://www.vre.org/feedback/frequently_asked_questions/faq_h...

Re: Hyperloop Alpha [pdf]

#156

Post by RyJones »

toomuchtodo wrote: post #142
RyJones wrote: post #94

Earlier quoted context omitted.

perhaps you can pour sections and truck those in, but there's no way in hell you're moving a precast that size on anything that doesn't float. For scale, you know those 4' by 4' by 8' blocks of cement you see all over the place, used for erosion control and the like? They're called ecology blocks, they're about $20 each FOB the cement plant. You want them shipped? A lowboy can carry two or four at a time without exce…

Pretty sure you can truck pylons if you can truck in precast bridge decks: https://www.google.com/search?q=precast+bridge+deck

Concrete is about two tons per yard. The legal limit on most trailers is about 20 tons (40,000 pounds, the trailer is about 40,000 for the legal limit of 80,000 pounds). So you can get about 10 yards of concrete in one go; you can use specialty trailers to get higher numbers, but even if you double it to 40 tons, that's still only 20 yards.

a 4' x 4' x 8' ecology block is about five yards. So let's picture the pylon having a 4' x 4' base that sits on granite, requiring no foundation. The pylon is going to max out at 16 or 32 feet tall if we're required to stay within the load limits.

furthermore, when you see those ribs moving around, they're moving around on interstates or state roads of solid construction. If there was an interstate running directly from San Francisco to Los Angeles along this route, we wouldn't be having the discussion. Building such a road to deliver precast sections is quite the endeavor.

I stand by my original claim that these would need to be cast-in-place.

Re: Hyperloop Alpha [pdf]

#157

Post by ianb »

resu wrote: post #21

If the U.S. doesn't take this on, I hope another country with a big appetite for enormous public transit projects takes this on. Japan, Korea, and China, I'm looking at you...

China seems set on a different path, but I guess you never know. Korea seems too small to benefit. And Japan perhaps too mountainous?

Looking at California: http://bit.ly/1eFevxA And Japan: http://bit.ly/19ZXwbJ I don't see any roads in Japan that are nearly as straight as I-5.

The places where this would make sense have destinations fairly far apart, but not too far apart, with somewhat amenable landscape between them. The Midwest would work, Australia, Russia. Probably Brazil, Argentina? Probably a bunch of connections in Africa or maybe the Mideast... but that wouldn't work for other reasons. East coast seems a bit cramped.

Re: Hyperloop Alpha [pdf]

#158

Post by kerneis »

bwaldrep wrote: post #150
Niten wrote: post #145

Earlier quoted context omitted.

Well it's not just a matter of bathrooms. Even on a commuter bus or plane, if someone has a medical emergency and needs to get off right now , the bus will pull over or the plane will land. In this design you'd have to just sit there, helpless, until the vehicle reaches its destination. Heck, even if you're a doctor in the next seat you wouldn't be able to get up and help your fellow passenger.

They discuss this in the paper. In the event of a medical emergency the pod will proceed to the destination as normal, and paramedics can be waiting at the end. In the absolute worst case you are looking at ~30 minutes before you can get to medical attention. That's not obviously worse than the time it would take a plane to descend from cruising altitude to the nearest airport, land, and taxi to a gate.

Except you can get first aid assistance in a plane (they ask if a doctor is here, and they have a number of drugs on board). Keeping the person alive until paramedics arrive is key to handling emergency situations, and I don't see how you do it with the Hyperloop.

Re: Hyperloop Alpha [pdf]

#159

Post by LockeWatts »

Niten wrote: post #145
orofino wrote: post #17

The focus from people on bathrooms is puzzling to me. I've been on buses, without facilities, that go for hours without stopping. This is a 35 minute ride with restricted movement, if you greatly fear being able to hold it for that long, there are other, less efficient methods of transport to accommodate you.

Well it's not just a matter of bathrooms. Even on a commuter bus or plane, if someone has a medical emergency and needs to get off right now , the bus will pull over or the plane will land. In this design you'd have to just sit there, helpless, until the vehicle reaches its destination. Heck, even if you're a doctor in the next seat you wouldn't be able to get up and help your fellow passenger.

Landing a plane will guaranteed take more than 35 minutes. With the hyperloop, it's simpler and more efficient to just have EMTs called and on station when the car arrives.

Re: Hyperloop Alpha [pdf]

#160

Post by LockeWatts »

ianb wrote: post #75
sylvinus wrote: post #70

IMHO Musk (or anyone who follows up) should drop the "passenger" version and go with the "passenger plus vehicle" version only. Because right now what people and the press are going to focus on is how small the cabins are, why there are no toilets, etc. On the other hand if you can imagine putting a car in there the claustrophobia argument disappears and you can think straight again...

It would seem to make the stations a lot more complicated – they'd need to handle the car loading, the accompanying traffic, and the security would be really challenging.

Can we not be thinking about adding the inefficiency of the TSA to such a nice system? The security theatre needs to end.
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