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Hyperloop

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Re: Hyperloop

#511

Post by cmsmith »

jessriedel wrote: post #281
jeffasinger wrote: post #229

Earlier quoted context omitted.

The tube is not nearly as wide or heavy as a traditional train, so I don't know that it's fair to say that you can just as easily put a train up on pylons as you could this tube. It's interesting to think about, but also there are probably much higher costs associated with a completely untested system like this than estimated. I wouldn't be surprised if this system, if it actually worked at all, ended up being more e…

But why make it a traditional train? Just build a lightweight train if it gets you all of the hyperloop's cost advantages without the additional costs and complexity of a tube?

Traditional trains have wheels and engines, which are quite heavy. And with a traditional train you're trying to minimize losses due to air resistance, which is not an issue in a low pressure tunnel.

Re: Hyperloop

#512

Post by seanmcdirmid »

snogglethorpe wrote: post #492
chrismealy wrote: post #367

Earlier quoted context omitted.

Thanks. By comparison HSR in Europe carries 300-500 people with three minute headways (according to wikipedia).

... and the Tokaido shinkansen carries 1300+ passengers per train, with up to about 15 trains per hour at peak times, so about 20,000 passengers / hour (per direction). At ~850 passengers / hour, Hyperloop seems like it's operating in another realm entirely.... Ironically, at Musk's "projected" low ticket prices (which granted probably aren't anywhere near realistic) and short travel times, one would expect a huge de…

The Tokaido shinkansen serves commuters in a very dense area. Also, Tokyo to Nagoya will run you a hundred bucks last time I rode.

Why would anyone want to live in LA and commute to SF, or vice versa? Even if ticket prices are low, property prices on both sides are very high. It would make much more sense to build a hyperloop to nowhere economically, and turn that area into a bedroom community.

Re: Hyperloop

#513

Post by dragonwriter »

mladenkovacevic wrote: post #174
Matti wrote: post #63

"Hyperloop Passenger Capsule The maximum width is 4.43 ft (1.35 m) and maximum height is 6.11 ft (1.10 m). With rounded corners, this is equivalent to a 15 ft2 (1.4 m2) frontal area, not including any propulsion or suspension components." At a first look I didn't get that the proposed passenger capsule would be so small. That's pretty cramped. Edit: Isn't the the ft to m conversion for the height wrong?

Yeah that should definitely be 2.10 meters

From the pictures, 1.10m heigth with 1.35m width looks more right; in any case, there's no simple typo:

If the feet are correct, (6.11 ft), then it should be 1.86m, not 1.10m (or 2.10m as you suggest.)

If the meters are correct (1.10m), it should be 3.61 ft (not 6.11 ft).

Re: Hyperloop

#514

Post by qohen »

dragonwriter wrote: post #448
qohen wrote: post #417

Earlier quoted context omitted.

The main cost of CAHSR will be the opportunity cost of not having built it. I wonder: this is from an LA Weekly article from 2011 -- I remember it being an eye-opener when I read it back then [1]: The authority had projected that 41 million people annually would ride the train between Anaheim and San Francisco, for example. But currently only 12 million customers fly nonstop on the extremely busy air route between Lo…

> The article goes on to say that Acela gets 3 million riders in the very dense east coast NY/Washington corridor but in less-dense California they were projecting a ridership around 10x of Acela's (!). And...so? California has dense areas in the north and south and a big (relatively) empty gap between them. California HSR is designed to connect those dense areas. The overall density of the state (or the corridor) is…

I'm not so sure it's a side-issue, in that the northeast corridor train routes don't just allow people in, say, NY to go to Washington, but also people in Philadelphia and Baltimore to go there as well, since those cities are on the Acela route.

And, if your city is not on the Acela route, you may well be able, due to the area's density, to take a commuter rail or another train to get to a city that is on the Acela route.

Similarly for Acela's Boston-NY route -- New Haven is on the route, so people from Connecticut can likely get to it.

And, of course, people in NJ can easily pop into NYC and grab Acela as well.

By contrast, the lack of density in CA would mean that aside from LA - SF (and a bit of traffic to and from Sacramento), you wouldn't likely have that sort of potential passenger-base.

Re: Hyperloop

#516

Post by politician »

mjn wrote: post #475
pbreit wrote: post #471

Earlier quoted context omitted.

Uh, the number above is $70b and the TGV was built 30+ years ago so you could at least double that number based on inflation.

Even the most expensive TGV lines, have a per-km cost of around $20m/km in present dollars, and that's high enough to cause controversy. The bulk of the network was built for prices of $2-4m/km at the time, which is about $3-5.5m/km if you adjust for inflation. For a 700-km line like SF-LA, even the $20m outlier cost would work out to only $14 billion. Where's the 8x multiplier coming from? No TGV line has cost >$100…

I'd just like to plug the Dictionary of Numbers chrome extension at this point which provides context for all of the numbers in this thread. For example, did you know that $14 billion [≈ net worth of Steve Ballmer, CEO of Microsoft]?

Re: Hyperloop

#517

Post by robryan »

rossjudson wrote: post #502
slacka wrote: post #290

Earlier quoted context omitted.

“The man who moved a mountain was the one who began carrying away small stones.” -Chinese Proverb I've lived in China for over 3 years, and spend countless hours riding the HSR system. HSR combines the speed of a plane, with the cost and convenience of a regular bus. Traveling through the countryside of China at 380km/h made me feel like I was in the future. Coming home and seeing the the sad state of our infrastruct…

I've been on one of the Chinese high speed trains and they are really impressive. The most striking thing about them is how smooth they are -- very little vibration at all, and very quiet. Far more pleasant than air travel, conventional trains, or anything else I've been on. Sadly, I think the first place a Hyperloop will be built is China. Chances are there are engineers there looking it over now, and figuring they…

That would be great, all you need is 1 country somewhere in the world to prove viable and it becomes a much safer political prospect elsewhere.

Until a major accident at least like with Fukushima and nuclear.

Re: Hyperloop

#518

Post by ricardobeat »

krschultz wrote: post #459

This is very serious first proposal. As a professional mechanical engineer I have worked on high quality steel tubes (nuclear submarines) before. The immediate thing that sticks out to me in this proposal are the tight mechanical tolerances that have to be maintained. Talking about tens of thousandths of an inch tolerances on a 10' diameter tube is not to be dismissed lightly. That is going to be tough to maintain -…

> I would image the tubes will be joined with automated friction stir welding or something similiar, but that will still require a fair amount of post weld machining which has its own pitfalls

The document mentions standard orbital seam wlelding, plus specialized machining equipment that travels along the tube to smooth out the gliding surface.

The capsules are only 60% the diameter of the tube, or 36% it's area (68/47% for the vehicle-carrying version), it doesn't seem to require tight tolerances for operation. I got the idea that tube distortion and movement is taken into account into the system.

Re: Hyperloop

#519

Post by MRSallee »

protomyth wrote: post #374
ewoodrich wrote: post #275

Earlier quoted context omitted.

It was approved by a ballot measure, so in this case it may be the "idiocy" (or will) of the voter. http://ballotpedia.org/wiki/index.php/California_Proposition...

They approved it at a much lower budget ($9.95 billion). It would be interesting for the voters to get another vote based on the current cost projections.

I honestly doubt the higher cost projections would change the vote -- when talking about that much money, most voters -- myself included -- can't really discern the impact of the difference between $10 billion and $70 billion.

The only hope would be that the anti-rail side could point to the growth of projections as either incompetence or out of control budgeting, which could both sway the vote. But I think if you go back to 2008 and say, "This will cost $100 billion," the vote would be the same.

Re: Hyperloop

#520

Post by marshray »

Turing_Machine wrote: post #347
asmithmd1 wrote: post #345

Earlier quoted context omitted.

Sure - but that is happening dozens of feet away inside a can designed to contain it. This extremely high temperature and pressure air will be flowing right under your butt. Serious question, Is any kind of breakthrough in insulation needed?

Well, if the can fails you're toast either way. :-) The pressure ratio for the compressors in the CFM56 engines in current model 737-800 models is 32.8:1, so somewhere in the neighborhood of 400-500 psi (will depend a lot on altitude). Seriously, we've been building machinery to operate safely in this pressure and temperature range for a long time.

Yes, and it involves a lot of the considerations we're bringing up here.

Engines do fail on passenger jetliners from time to time. There are numerous stories of planes landing safely after an engine catches fire. But the plane is travelling at a good speed through the atmosphere. How would things be different in a much smaller vehicle sitting stationary in a mild vacuum?

How would passengers escape a battery fire? (as has been seen multiple times on very modern jets)

If the tube had to be repressurized in an emergency, how long would the tube be out of service to be pumped back down again?

Is it worth building a three tube system for such a possibility?

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