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Hyperloop

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Re: Hyperloop

#451

Post by numbsafari »

RyanZAG wrote: post #143
dictum wrote: post #99

I'm impressed, but I'm afraid Hyperloop's operation is modeled after airplanes, while the actual use of the system would be closer to a city bus. >All capsules would have direct radio contact with station operators in case of emergencies, allowing passengers to report any incident, to request help and to receive assistance. In addition, all capsules would be fitted with first aid equipment >Typical times between an e…

What happens if a brawl erupts inside a moving bus or taxi? What happens if a suicide bomber boards a train or bus? What happens if a suicide bomber rents a car and crashes it into you as you walk along the sidewalk? Rather than living in perpetual fear, you could try making the world a place where people who can't get food or work aren't trying to blow you up as a last resort? Americans seem to be the most worried a…

Americans seem to be the most worried about suicide bombings out of anybody else, yet America has probably seen the least suicide bombings per capita of any country in the world.

Not that I approve of many of the things we do to "prevent" them, but...

Perhaps worrying about preventing certain things sometimes actually helps reduce them?

Re: Hyperloop

#452

Post by flomo »

rayiner wrote: post #407
flomo wrote: post #385

Earlier quoted context omitted.

> Can you please clarify why the high speed rail is likely to be a debacle ? I don't believe that high speed rail will necessarily be a debacle. But the route was largely chosen for political considerations. It was decided downtown San Jose, Fresno, and Bakersfield must have stations. (This requires an additional long tunnel, and urban construction is much more expensive.) The route takes a detour through Palmdale[1]…

Counterpoint: rail that doesn't run through urban areas is far less useful. There is a reason Amtrak is taking over the northeast corridor: it's tough to beat to convenience of being able to walk from your office in manhattan to your office in DC without ever leaving public transit.

I agree to some extent.

However, CA-HSR chose the nearly the most complex and expensive route possible (even though they don't have a funding source), so we shouldn't make a direct cost comparison with Musk's route down I-5. HSR would also be much cheaper on the mostly unpopulated I-5 corridor. Also, the right-of-ways that Musk proposes to get into SF and LA are sketchy.

(Silicon Valley business interests wanted the HSR stations in San Jose & Mountain View, and apparently quite interested in using lower-cost areas such as Fresno for back-office activities. So while they will be impressed by Hyperloop's techno-wizardry, they may actually prefer the HSR project.)

Re: Hyperloop

#453

Post by anigbrowl »

rayiner wrote: post #401
melling wrote: post #59

Earlier quoted context omitted.

So, we have "light shed" on the current "debacle" and neither system gets built. That's a win? HSR was first commerically available in 1964. Yes, it got really expensive waiting 50 years. I imagine it'll be even more expensive in another 20-30. California is going to get even more crowded.

California will get more crowded, but it will continue to be a disaster of urban planning, limiting the utility of HSR. It's mind boggling to me that the California HSR isn't being built from DC to Boston instead.

There are actually some serious efforts in place to get sanity back into urban planning, but (predictably I suppose) this is regarded as an attack on freedom and the lawsuits have already begun to fly.

Re: Hyperloop

#454

Post by lnanek2 »

evan_ wrote: post #118

I thought Musk said it wasn't an evacuated tube. Does it not count because it's very low air pressure and not a completely hard vacuum?

I think it's fair that he said that. A vacuum tube has as little air as possible to help things move. His paper explicitly says it is more cost effective to have some air and his capsule design depends on air as a levitation cushion. If he had said it was a vacuum tube, no one could have guessed the levitation method.

Re: Hyperloop

#455

Post by gsnedders »

arrrg wrote: post #170
r00fus wrote: post #82

Earlier quoted context omitted.

What happens currently on a high-speed rail system? I suppose there's a lavatory in the HSR (e.g.: France's TGV).

Fast trains are just fast trains. Inside there isn’t much special about them compared to slower ones, except that they are usually more comfortable (softer and adjustable seats, definitely wider, at least in first class, better and more tables, more storage space for luggage, electrical outlets, sometimes crappy WiFi, a crappy restaurant, relatively roomy bathrooms that don’t even look that bad). Also, they actually…

In general, most of those things vary massively between classes of trains, and there's no simple low-speed/high-speed distinction. Seat width varies massively between body shell designs, softness often depends on how long since the last refurbishment more than anything else, number of tables and luggage space are often based on the target market for the class, electrical outlets are more and more common (even on commuter trains), WiFi is something I'd expect on most inter-city trains, and on-train restaurants (sadly) are dying out though have historically been common on all inter-city trains.

Smoothness is mostly due to track quality, and is a practical result of design for high-speed running.

Re: Hyperloop

#456

Post by Turing_Machine »

clebio wrote: post #84

> 4.5.6. Human Related Incidents Hyperloop would feature the same high level of security used at airports. However, the regular departure of Hyperloop capsules would result in a steadier and faster flow of passengers through security screening compared to airports. Ugh. That only seems feasible if back-scatter scanners are the only option (but would you still have to take your belt off and put all metal in a little b…

You'd really only have to scan for explosives.

Knives or even guns would only pose a problem to the few passengers in the capsule with you (yeah, you might be able to shoot a hole through the tube, but it would take a LONG TIME for a bullet hole to let in enough air to affect the pressure in a LA-SF-sized tube).

It's not like you can hijack the thing. :-)

Re: Hyperloop

#457

Post by apendleton »

jessriedel wrote: post #389
apendleton wrote: post #350

Earlier quoted context omitted.

You can't just make lighter trains; heavy rail is heavy because it has high capacity. These vehicles can be much lower-capacity per vehicle because the speed is very high, which means you get equivalent throughput even with much smaller per-vehicle capacity. It's just like how you can get the same amount of water through a high-pressure, low-diameter pipe as through a low-pressure, high-diameter pipe. So yes, you cou…

I would be very surprised if the numbers really work out the way you claim: that the weight for carrying a passanger is similar for trains and a tube, and that the weight advantage of a tube comes essentially from 3x speed allowing for a one third the linear density of passengers. Do you have a cite?

No, this is just back-of-the envelope, admittedly. But the three factors that determine how many people you can move past a given point per unit of time are the frequency of the vehicles, the capacity of the vehicles, and the speed of the vehicles, so if you want to match the throughput of the proposed Hyperloop, but with rail traveling at 164mph, you have to either make the vehicles more frequent or higher-capacity, or both. I would expect rail to be much less frequent, at least if typical rail conventions are followed, meaning you'd need much higher-capacity vehicles, combined with the engines to bring them up to speed (which move along with the train). It doesn't take that much weight to get past what you could reasonably support on a pylon in a median... there's a reason inter-city rail isn't built this way.

Re: Hyperloop

#458

Post by jfb »

mcintyre1994 wrote: post #424
jfb wrote: post #379

Earlier quoted context omitted.

Well, fast trains or no new trains. It is still technically possible to get on BART in San Francisco and get off from a train in Los Angeles. You wouldn't choose to do this -- nobody would choose to do this [1] -- but it is possible. [1] http://www.nytimes.com/2009/06/14/magazine/14Train-t.html?pa...

I see, fair enough, cheers for pointing that out. I'm in the UK and we're pretty well connected by rail, I wasn't expecting the alternative to be that ridiculous, just normal slower trains.

Rail in California is sadly a total joke.

Re: Hyperloop

#459

Post by krschultz »

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 - especially with welding heat distortion. 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. Not to mention simple thermal expansion and contraction as the temperature changes could change the circularity and inner diameter.

I would be more interested to see a tolerance stack up of those considerations than an FEA model of the concrete pylons. I can gaurentee that we can build concrete pylons capable of holding up a steel tube, that is done all over the country dozens of different uses cases. But can we build a multi-hundred mile long steel tube to the required tolerances?

I would be inclined to trade off efficiency for manufacturability. I.e. maybe a higher internal pressure or larger diameter to make it less sensitive. There should be plenty of power from the solar panels so it doesn't have to be perfectly efficient.

I'm also surprised that the I-5 plan is cheaper than buying private land. I may be naive here, but the pylons really do take away most of the objections from farmers and installing tubes over farmland has to be a lot cheaper than doing construction above a highway. I just look at boondoggle that was the SkyTrain in NYC (tram running over a highway out to JFK airport) and wonder if that is a great option.

Re: Hyperloop

#460

Post by jfb »

dnautics wrote: post #436
jfb wrote: post #404

Earlier quoted context omitted.

It seems to me that to really force the issue, you'd need to be talking an order of magnitude difference in cost. For $20 r/t, ears would perk up -- even people who aren't making a $1/yr salary could conceivably afford that. But $120?

you speak as though it needs to be run as a charity to be a game changer. I only mention that price point because that is just underneath the cost of flying, and that's how economics works. The operator will likely want to make as much profit as it can, while still sucking customers away from the airports. In the beginning, the operator will likely charge MORE than the airplanes, because the customer will be liable t…

You have to get the thing built before you can start charging a premium for it. Without a strong constituency, you can't get a giant infrastructure project off the ground. If your constituency is people like me, who can afford to fly, you've already lost the game.
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