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Hyperloop

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Re: Hyperloop

#881

Post by anigbrowl »

saalweachter wrote: post #849
gojomo wrote: post #582

Earlier quoted context omitted.

I can believe that's a good plan for the US NE corridor... which already has usable (but improvable) Amtrak. The California coastal cities (and connecting areas) are still pretty sparse, comparatively. And the marquee High Speed Rail project takes a big inland detour to the smaller interior cities, for political reasons. If ever finished, that will hurt its price/time attractiveness compared to flying.

The US NE corridor is arguably the only place it makes sense to build a high speed train network. You'll notice that Elon Musk's plan for the Hyperloop includes an option for shooting automobiles through the tubes . That's because the mass transit within the cities on that coast is shit. Inter-city mass transit only makes sense once you've solved intra-city mass transit. Unless you really, really love hanging out wit…

That's because the mass transit within the cities on that coast is shit.

As someone who uses only mass transit, I think that's untrue.

Re: Hyperloop

#882

Post by jholman »

6ren wrote: post #862
Anechoic wrote: post #789

Earlier quoted context omitted.

Vibration from trains is proportional to the unsprung weight of the vehicle (basically the axle, wheels and traction motors) rather than the vibration of the whole vehicle (which is isolated by the primary and secondary train suspensions). For a heavy rail transit vehicle (NYC transit, MBTA Red Line, CTA vehicle, etc), you're talking about 2,700 kg. I don't have numbers handy for HSR trainsets.

The air cushion isolates the entire vehicle... perhaps making the "unsprung" weight 0?

The plan uses an air bearing partly because an air bearing is exceptionally stiff. It's not like a hovercraft, with all that ability to squoosh up and down. So the unsprung weight might be the weight of the entire vehicle.

edit: though, mind you, the whole capsule also has mechanical suspension

Re: Hyperloop

#883

Post by anigbrowl »

thrownaway2424 wrote: post #689
jarek wrote: post #643

Earlier quoted context omitted.

> CA HSR replaces/upgrades two metropolitan rail systems (Caltrain/Metrolink) in addition to connecting SF (as opposed to Oakland!) and LA, requires no R&D, is supposed to handle significantly greater ridership, has detailed cost estimates which include things like take into account electrification costs (because it does get cloudy), support facilities (because there is maintenance of these cars), administrative buil…

To be fair, Oakland is a much more sensible location of the initial terminal for any rail system. It's very well-connected to SF, has a complete lack of powerful, moneyed NIMBYs, and it would be easy to punch the line through to SF once it's proven.

Ahahaha no. I live in Oakland, you're quite wrong. On the upside I do like that I can walk a short distance to catch a train that will take me to LA :)

Re: Hyperloop

#884

Post by jholman »

ricardobeat wrote: post #518
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/…

> it doesn't seem to require tight tolerances for operation

Well, it's true that the top and sides of the tube don't get too close to the capsule, so those parts seem relatively low-tolerance, as you say.

But the load-bearing skis ride on an air bearing of 0.5mm to 1.3mm (see page 20), moving at over 1000km/h. As rossjudson notes, the skis are on mechanical suspension, to smooth out shocks to the riders, but it's not clear (to ignorant me) how much of a bump those skis can glide over. 0.1mm, no problem. What about 1.0mm?

On a related note, Musk seems sanguine about the sag you'd get in any structure supported by pylons (see e.g. page 27). Even with inch-thick steel walls, with pylons an average of 30m apart (100'), you'll see some sag, right? Any engineers want to comment on the deviation in 30m of inch-diameter-wall steel tubing? Let's see, 1200kph, 30m, so you pass a pylon 11 times per second. So in 0.09 seconds, you have to go from the top of one pylon, to the valley between two pylons, and back to the top of the next pylon. I guess that's all absorbed by the mechanical suspension?

Re: Hyperloop

#885

Post by anigbrowl »

rayiner wrote: post #578
hyperbovine wrote: post #410

Earlier quoted context omitted.

Uhm, LA alone has more people than DC and Boston combined. Plus another 9 million living in the Bay Area. This is far and away the most obvious candidate for direct HSR in all of North America.

The core cities on the DC BAL PHL NYC BOS route total 11.5 million, while LA + SF is only 4.5 million. Thats arguably the more important figure because the relative advsntage of rail diminishes if you have to drive in from the suburbs. Also, four of those five cities have well developed public transit systems centered around the rail station. Metro area total for the five cities is not including any other regions in…

Ah, our light rail network is a bit more extensive than you seem to imagine.

Re: Hyperloop

#886

Post by anigbrowl »

jacoblyles wrote: post #355
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…

My bet is that Elon could build the Hyperloop closer to budget than the state of California could build a traditional train. Leadership matters.

My bet is that people in the middle who don't get any benefit from it will prove just as obsrtuctive as they are towards any other large scale infrastructure project.

Re: Hyperloop

#887

Post by Aloisius »

thrownaway2424 wrote: post #689
jarek wrote: post #643

Earlier quoted context omitted.

> CA HSR replaces/upgrades two metropolitan rail systems (Caltrain/Metrolink) in addition to connecting SF (as opposed to Oakland!) and LA, requires no R&D, is supposed to handle significantly greater ridership, has detailed cost estimates which include things like take into account electrification costs (because it does get cloudy), support facilities (because there is maintenance of these cars), administrative buil…

To be fair, Oakland is a much more sensible location of the initial terminal for any rail system. It's very well-connected to SF, has a complete lack of powerful, moneyed NIMBYs, and it would be easy to punch the line through to SF once it's proven.

The estimated ridership of even the Hyperloop is high enough that it would crush the Bay Bridge even if a majority used BART. Not to mention add an hour to the transit to people going to San Jose.

Oakland was chosen to make this thing look cheaper, not because it makes sense from a civil planning perspective.

Re: Hyperloop

#888

Post by jarek »

Aloisius wrote: post #887
thrownaway2424 wrote: post #689

Earlier quoted context omitted.

To be fair, Oakland is a much more sensible location of the initial terminal for any rail system. It's very well-connected to SF, has a complete lack of powerful, moneyed NIMBYs, and it would be easy to punch the line through to SF once it's proven.

The estimated ridership of even the Hyperloop is high enough that it would crush the Bay Bridge even if a majority used BART. Not to mention add an hour to the transit to people going to San Jose. Oakland was chosen to make this thing look cheaper, not because it makes sense from a civil planning perspective.

The capacity of the proposed system at 28-person capsules every 30 seconds is 3360 pph at peak. Three thousand more people per hour would crush the Bay Bridge?

Re: Hyperloop

#889

Post by warfangle »

iamjustin wrote: post #507
javert wrote: post #428

Earlier quoted context omitted.

> Musk should do what the Germans did with the TR0x series of maglev vehicles Musk has already given more than enough for the world and done more than enough. Somebody should do it, but we should not expect him to do it.

We shouldn't expect him to demonstrate his idea?

He noted (just today!) that he'll be working on a subscale demonstration of the technology.

Re: Hyperloop

#890

Post by saalweachter »

anigbrowl wrote: post #881
saalweachter wrote: post #849

Earlier quoted context omitted.

The US NE corridor is arguably the only place it makes sense to build a high speed train network. You'll notice that Elon Musk's plan for the Hyperloop includes an option for shooting automobiles through the tubes . That's because the mass transit within the cities on that coast is shit. Inter-city mass transit only makes sense once you've solved intra-city mass transit. Unless you really, really love hanging out wit…

That's because the mass transit within the cities on that coast is shit. As someone who uses only mass transit, I think that's untrue.

I was going to make a flippant comment about "Congratulations on living in San Francisco!", but hilariously, there's a better chance you live in Los Angeles (lower ridership percentage, but significantly higher population).

Even in Oklahoma City, where only ~1% of people commute via mass transit, there are still thousands of people who can live happily without a car because mass transit serves them fine. That does not mean that Oklahoma City has a great transit system.

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