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Hyperloop Freight is a Joke

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Re: Hyperloop Freight is a Joke

#81

Post by nickparker »

Animats wrote: post #73

Vactrains might work out. There's nothing wrong with maglev in an evacuated tube. A system where the thing runs on open track until it gets out of the city and can switch to a vacuum tube might work. Then you can get someplace useful. Most of the "hyperloop" proposals, including the MIT demo, are really maglev vactrains. If you're already a maglev, a tube doesn't add much. Japan's maglev has already reached 600 Km/h.…

Hypothetically, the vacuum tube gives you energy efficiency.

Drag power is proportional to the cube of velocity, so drag energy losses over a fixed distance are proportional to the square.

In an ideal world you're paying a fixed cost per unit time to pump the tube down then you shove as much stuff as you can through it at transsonic speed, catch it all with regenerative brakes at the other end, and pay an energy per kg payload cost lower than electric road vehicles.

Of course in practice that fixed cost may turn out astronomically high, but that's the idea.

Re: Hyperloop Freight is a Joke

#82

Post by D_Alex »

LordHumungous wrote: post #62

Of course the hyperloop is a joke. Elon Musk has zero experience or training in transportation infrastructure, but we are supposed to have faith in some idea he farted out in a white paper, why? Because he has skillfully cultivated his image as a "genius", and we bought it? The hyperloop was nothing more than a (savvy) PR move to cement his image as a "visionary". That it actually got funded only goes to show what gu…

Elon Musk had zero experience building cars, yet he made Tesla happen. Perhaps a high intellect and a good general purpose engineering training can accomplish more than you think.

You, on the other hand, are overwhelmed by the challenge of maintaining vacuum in a tube that spans a mere 17 miles. At the very least, you should restrain yourself from using language like "...some idea he farted out...".

Re: Hyperloop Freight is a Joke

#83

Post by LordHumungous »

Omniusaspirer wrote: post #68
LordHumungous wrote: post #62

Of course the hyperloop is a joke. Elon Musk has zero experience or training in transportation infrastructure, but we are supposed to have faith in some idea he farted out in a white paper, why? Because he has skillfully cultivated his image as a "genius", and we bought it? The hyperloop was nothing more than a (savvy) PR move to cement his image as a "visionary". That it actually got funded only goes to show what gu…

Would you be able to tell us about some of the problems the LHC faced? Hyperloop aside, this is an interesting subject.

The tolerances on each part must be very tight. If there is a single flaw in one part, the whole vacuum fails. The challenges become exponentially greater as you scale up the diameter of the pipe, since the force on the pipe is proportional to the square of the radius. The LHC had a 50mm diameter pipe, the hyperloop proposes an 8+ foot diameter. You do the math.

Re: Hyperloop Freight is a Joke

#84

Post by agumonkey »

D_Alex wrote: post #82
LordHumungous wrote: post #62

Of course the hyperloop is a joke. Elon Musk has zero experience or training in transportation infrastructure, but we are supposed to have faith in some idea he farted out in a white paper, why? Because he has skillfully cultivated his image as a "genius", and we bought it? The hyperloop was nothing more than a (savvy) PR move to cement his image as a "visionary". That it actually got funded only goes to show what gu…

Elon Musk had zero experience building cars, yet he made Tesla happen. Perhaps a high intellect and a good general purpose engineering training can accomplish more than you think. You, on the other hand, are overwhelmed by the challenge of maintaining vacuum in a tube that spans a mere 17 miles. At the very least, you should restrain yourself from using language like "...some idea he farted out...".

I don't think he was alone in this, if he says it was hard, I'd assume it was hard for a whole team of world class physicists and engineers.

Re: Hyperloop Freight is a Joke

#85

Post by bertiewhykovich »

D_Alex wrote: post #82
LordHumungous wrote: post #62

Of course the hyperloop is a joke. Elon Musk has zero experience or training in transportation infrastructure, but we are supposed to have faith in some idea he farted out in a white paper, why? Because he has skillfully cultivated his image as a "genius", and we bought it? The hyperloop was nothing more than a (savvy) PR move to cement his image as a "visionary". That it actually got funded only goes to show what gu…

Elon Musk had zero experience building cars, yet he made Tesla happen. Perhaps a high intellect and a good general purpose engineering training can accomplish more than you think. You, on the other hand, are overwhelmed by the challenge of maintaining vacuum in a tube that spans a mere 17 miles. At the very least, you should restrain yourself from using language like "...some idea he farted out...".

Given that the Hyperloop is failing spectacularly, "a high intellect and a good general purpose engineering training" seem empirically to not accomplish quite as much as you think they do -- although, in fairness to high intellect and good general purpose engineering training, there was never any real reason to think that they'd be able to accomplish magic.

Re: Hyperloop Freight is a Joke

#86

Post by Someone »

LordHumungous wrote: post #62

Of course the hyperloop is a joke. Elon Musk has zero experience or training in transportation infrastructure, but we are supposed to have faith in some idea he farted out in a white paper, why? Because he has skillfully cultivated his image as a "genius", and we bought it? The hyperloop was nothing more than a (savvy) PR move to cement his image as a "visionary". That it actually got funded only goes to show what gu…

The LHC has lower pressure than Hyperloop is supposed to have (1E-7 pascal, reading http://www.lhc-closer.es/taking_a_closer_look_at_lhc/0.high_... versus 100 pascal, reading https://en.m.wikipedia.org/wiki/Hyperloop#Theory_and_operati...)

Still quite challenging, but not in the same league, even considering that hyperloop requires way longer tunnels.

Re: Hyperloop Freight is a Joke

#87

Post by LordHumungous »

Turing_Machine wrote: post #79
LordHumungous wrote: post #62

Of course the hyperloop is a joke. Elon Musk has zero experience or training in transportation infrastructure, but we are supposed to have faith in some idea he farted out in a white paper, why? Because he has skillfully cultivated his image as a "genius", and we bought it? The hyperloop was nothing more than a (savvy) PR move to cement his image as a "visionary". That it actually got funded only goes to show what gu…

"The challenges of maintaining a closed vacuum pipe that spanned a mere 17 miles were vast and expensive." The vacuum level required for a particle accelerator (10^-11 torr or something like that) and the one posited for the Hyperloop (0.75 torr) are so far apart that they have virtually nothing in common.

That is actually a valid point, Musk only proposes a partial vacuum which is a lot different from a pure vacuum. However, I think that is still a lot to ask for heavily used transit infrastructure.

Re: Hyperloop Freight is a Joke

#88

Post by Turing_Machine »

LordHumungous wrote: post #83
Omniusaspirer wrote: post #68

Earlier quoted context omitted.

Would you be able to tell us about some of the problems the LHC faced? Hyperloop aside, this is an interesting subject.

The tolerances on each part must be very tight. If there is a single flaw in one part, the whole vacuum fails. The challenges become exponentially greater as you scale up the diameter of the pipe, since the force on the pipe is proportional to the square of the radius. The LHC had a 50mm diameter pipe, the hyperloop proposes an 8+ foot diameter. You do the math.

The Hyperloop will operate at about 15 psi pressure differential maximum (i.e., one atmosphere).

The Alaska Pipeline is certified to operate at 1,180 psi.

It's not a problem, and minor leaks are not a problem, either. A leak that would stop a particle accelerator dead in its tracks will just make a hyperloop operate at slightly lower efficiency. Plus you can always just run the pump (any practical design will doubtless have the pumps running continously to make up for leakage, just as many ships and buildings have continuously-running bilge and sump pumps).

Re: Hyperloop Freight is a Joke

#89

Post by bigger_cheese »

toomanybeersies wrote: post #66
bigger_cheese wrote: post #57

One thing the article misses is inflexibility. One of the big disadvantages of rail is that once the track is deployed it is very costly and difficult to upgrade it. One thing I'd want in any "futuristic" freight hauling method would be ease of scaling I don't think Hyperloop offers anything over rail in this regard once track is installed you are more or less stuck with the installed capacity forever. A computer ana…

> A computer analogy I'd give is to think of freight handling like information communication Unsurprisingly, a lot of the theory for transport networks maps extremely well to computer networks. Transport is essentially a literal packet switched network. You have routers (depots), routes (roads, rails, etc), packets (in many cases, literally packets), MTUs (twenty foot containers, or truckloads). Queuing theory equall…

Anecdotally one of my Engineering lecturers at university was an expert on human logistics. (i.e the physical queuing of people) I remember talking to her about a project she was working on with a large retail chain advising them on how to funnel people through store checkouts more efficiently.

Re: Hyperloop Freight is a Joke

#90

Post by mangeletti »

kinofcain wrote: post #54
mangeletti wrote: post #48

Earlier quoted context omitted.

I don't mean as a means to maximize efficiency, but to avoid a lot of the problems (e.g., the risks of a vacuum, the cost of engineering one, etc.).

Instead of the air resistance of a train-sized object (about a quarter mile long) you'd have air resistance equivalent to a train 300 miles long (think of the tunnel as an inside out train). It's inefficient by several orders of magnitude.

Ah, I see what you mean :/

EDIT:

Wait, if the walls were made to be near frictionless, then the aggregate energy, minus what's lost to hear from turbulence, would be used for motion, right?

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