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Hyperloop: Pipes of Fancy

economist.com

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Re: Hyperloop: Pipes of Fancy

#81

Post by disk0 »

AlexandrB wrote: post #9

This is evergreen when talking about Hyperloop: http://www.cat-bus.com/2017/12/gadgetbahn/ The problems with building this have nothing to do with technology but with right-of-way, investment, and politics. If those factors were solved, we'd already have high-speed rail in places where Hyperloop has been proposed. The fact that we don't says that Hyperloop is unlikely to be feasible as well.

first time I heard that term was in donoteat01's video on the loop[0], haven't got around to reading that post till now though (thanks for the reminder)

[0] Elon Musk's "Loop" - It's bad, folks https://youtu.be/4dn6ZVpJLxs

Re: Hyperloop: Pipes of Fancy

#82

Post by Alupis »

ricardobeat wrote: post #79
Alupis wrote: post #64

Earlier quoted context omitted.

Without paying US prevailing market wages to the contractors. Also, all the materials used on the Hawaii rail line have to be shipped in - literally, adding expense.

You should take a second look at that. Average wages in China are $12k/year, only a third of the US, but higher in the industrial areas, and in terms of purchasing power it has surpassed every other country long ago since everything is so cheap at scale. They have half a billion people in the middle class.

When you are directly comparing how much something cost to build, such as a mile of track, in USD, Purchase Power doesn't matter, does it? This is what the Parent post was asserting.

China builds a mile of track at half the price because they literally pay their people half the price (or less). It doesn't matter that their local Purchase Power might be greater.

Taking it a step further, the Parent was comparing a mile of track in China to a mile of track in Hawaii, which literally has to ship all supplies, and likely a lot of labor, across an ocean. So it's not a great comparison even if we remove labor costs.

Re: Hyperloop: Pipes of Fancy

#83

Post by jcranmer »

TigeriusKirk wrote: post #67
ashtonkem wrote: post #63

Earlier quoted context omitted.

This seems worse than a subway in pretty much every metric, unless if you happen to be same person who's selling the cars that it's compatible with.

There are a number of metrics where it's clearly better. Scheduling and routing. Not waiting 10-30 minutes for the next train depending on time of day. Not stopping anywhere but your destination. No connections or changeovers. Personal space. Privacy, safety. Regardless of how you personally feel about this factor, it matters enough to some people to significantly impact usage. Those factors may or may not be enough…

Loop is basically a personal rapid transit system, which is an idea that keeps getting proposed for basically the reasons you cite, but the few implementations that do exist have generally underwhelmed.

Re: Hyperloop: Pipes of Fancy

#84

Post by andbberger »

TigeriusKirk wrote: post #67
ashtonkem wrote: post #63

Earlier quoted context omitted.

This seems worse than a subway in pretty much every metric, unless if you happen to be same person who's selling the cars that it's compatible with.

There are a number of metrics where it's clearly better. Scheduling and routing. Not waiting 10-30 minutes for the next train depending on time of day. Not stopping anywhere but your destination. No connections or changeovers. Personal space. Privacy, safety. Regardless of how you personally feel about this factor, it matters enough to some people to significantly impact usage. Those factors may or may not be enough…

Waiting 10-30 minutes for a train isn't a technological consequence of rail transportation, it's a symptom of a catastrophically inept transit agency.

What's stopping, say, Caltrain, from running trains at peak frequency all day? Incompetent leadership. They have the trains (which spend all day sitting idle _at_ terminus platforms), the have the crew (who also sit idle during the day), they have the capacity to run more trains off peak. They made a deliberate choice to not run the trains.

You might make the case that running more trains off-peak would increase maintenance costs. But I would wager that such maintenance costs pale in comparison to the cost of building enough platforms at your downtown termini to store trains all day. Moreover who cares about maintenance costs? It's insane to think that public transit should be profitable.

loop is an elitist perversion of transit

Re: Hyperloop: Pipes of Fancy

#85

Post by captainbland »

riffic wrote: post #65
jeffreyrogers wrote: post #5

Hyperloop has sex appeal, but it seems like Maglev or just plain old high speed rail makes more sense from an economics perspective. I can't imagine it's cheap to keep a tube evacuated. Either way, it seems good to try and build these sort of high-tech industries in the US.

common misconception. Hyperloop tubes were never meant to be fully evacuated, they operate at pressure differentials with air bearings (imagine a cylindrical air hockey table).

It may not be totally evacuated but the pressure difference between it and the outside world is still supposed to be very large isn't it? And if you want a hyperloop that actually goes anywhere that's going to represent quite a large volume of low pressure space that you need to create and maintain.

Surely this has to be quite energy intensive and generally difficult to maintain, especially since you have to get people in and out of it all the time. I'm not saying these problems are physically insurmountable but they sure sound expensive.

Re: Hyperloop: Pipes of Fancy

#86

Post by jcranmer »

shajznnckfke wrote: post #78
ponker wrote: post #54

Earlier quoted context omitted.

It uses a much smaller tunnel.

Why does a hyperloop fit in a smaller tunnel than a train? Doesn’t it need to do everything a train does, plus it’s wrapped in a vacuum tube?

As far as I understand, the original proposal relies on a) no safety egress walkways in the tunnel and b) a more cramped vehicle profile.

I don't know how as-actually-built hyperloop compares to rail tunnels.

Re: Hyperloop: Pipes of Fancy

#87

Post by vwat »

brunoqc wrote: post #3

https://youtu.be/2h6Cz4hwuEI How legit is that video and YouTuber?

It’s not legit at all. I’ve always been a fan, and all his busted videos in the past featured one very important feature: the violation of thermodynamics. He always showed why a product was physically impossible. But he doesn’t do that with a hyperloop. And ultimately, if you see through the repetition and downright nastiness, you see that his argument is essentially “hyperloop is very expensive, it would be unsafe and render artists don’t know science.” I wouldn’t have minded if he hadn’t taken that low shot at Elon when a rocket blew up on the pad. Honestly, I don’t think it’s a coincidence that he started targeting Elon, with the sudden and notable lack of violation-of-physics, around the same time he started pushing his channel to have more engagement and make more money.

TLDR: I’ve seen all his videos and his hyperloop videos basically lack substance. Scott Manley is a much better source of opinions on such things.

Re: Hyperloop: Pipes of Fancy

#88

Post by masswerk »

What I'm failing to understand about the Hyperloop concept (apart from all the issues with thermal expansion, maintaining a near vacuum, safety consideration and passenger capacity):

In real life tracks will have to include curves, as there's already terrain, existing buildings, etc. Trains have to lean into curves, just like motorbikes. With high speeds, anything exceeding a more traditional maglev train, the angles required will become rather extreme with the track climbing up the sides of the tube. What is supposed to happen, if the train has to decrease speed below the planned cruising speed for the given section or even to halt? What about passengers inside? How could this pass any safety checks for mass transport operations?

(Notably, this was the only new thing addressed by Musk's original "air hockey puck", front fan driven air cushion concept, as this could have avoided any fixed installations, like rails or guards, (at the cost of other stability issues) and could have allowed a variable leaning angle. But, since this feature has been universally dismissed, how is this supposed to work?)

Re: Hyperloop: Pipes of Fancy

#89

Post by jcranmer »

andbberger wrote: post #84
TigeriusKirk wrote: post #67

Earlier quoted context omitted.

There are a number of metrics where it's clearly better. Scheduling and routing. Not waiting 10-30 minutes for the next train depending on time of day. Not stopping anywhere but your destination. No connections or changeovers. Personal space. Privacy, safety. Regardless of how you personally feel about this factor, it matters enough to some people to significantly impact usage. Those factors may or may not be enough…

Waiting 10-30 minutes for a train isn't a technological consequence of rail transportation, it's a symptom of a catastrophically inept transit agency. What's stopping, say, Caltrain, from running trains at peak frequency all day? Incompetent leadership. They have the trains (which spend all day sitting idle _at_ terminus platforms), the have the crew (who also sit idle during the day), they have the capacity to run m…

> You might make the case that running more trains off-peak would increase maintenance costs.

Alon Levy has done the math [1] and found that providing extra off-peak service is about 20% the cost of providing extra peak service, since the capital costs and labor costs dominate the actual operational costs.

[1] https://pedestrianobservations.com/2018/01/22/base-train-ser...

Re: Hyperloop: Pipes of Fancy

#90

Post by liability »

TylerE wrote: post #56
jengleton wrote: post #55

Earlier quoted context omitted.

You might not want to pop the emergency hatch when you're surrounded by vacuum.

Hatch in the tube, not the car.

Heh, look up "vacuum cannon" on youtube. The tunnel would need to be slowly depressurized, otherwise anything in it would turn into a bullet when the atmosphere rushes in.

This also applies to any sort of failure that compromises the vacuum. A dipshit with a rifle could kill anybody in the system in a fraction of a second. Burying the tubes is probably the only way to avoid this, but thankfully the whole thing is vaporware anyway.

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