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Hyperloop: Pipes of Fancy

economist.com

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Re: Hyperloop: Pipes of Fancy

#311

Post by Skye »

_ph_ wrote: post #271
Skye wrote: post #245

Earlier quoted context omitted.

I have a few nitpicks... Making train tunnels cheaper by making them smaller is not a new idea. it is a very old idea. Have a look at the deep level tube lines of the London underground. In some ways, we regret having trains that small since it reduces capacity and makes it nigh impossible to air condition. It's possible to make normal trains go over existing roads, elevated rail is also a very old thing, a lot of it…

Normal trains are designed to support very high loads, as they are using tracks suitable for cargo transport. For urben people transport, you don't need that carrying capacity, so the rails as well as the trains are unnecessarily heavy. Also, the wagons are larger than needed. It absolutely makes sense to rethink the whole system.

There is such a thing as "light rail" though. Lighter tracks, lighter trains, and cheaper construction.

Also if you want small trains, just look at the UK. Normal trains here are much narrower than normal US trains, they are about as wide as modern trams! And the London underground has trains that are tiny and shaped to make the most out of circular tunnels.

You don't need to rethink the entire system for the points you've raised there...

Re: Hyperloop: Pipes of Fancy

#312

Post by sudosysgen »

Ajedi32 wrote: post #308
sudosysgen wrote: post #298

Earlier quoted context omitted.

You need people to drive their cars safely into the intake with an average delay of two seconds, to match a very middling subway system running at a delay of 7 minutes instead of 2, assuming that every single car is filled to the brim. This is completely ridiculous. You won't be able to make people do anything with an average delay of 2 seconds, without any mistakes. The question isn't on-ramps, it's getting people t…

Ah, I see the misunderstanding here. Nobody will be driving in these tunnels. Only fully autonomous cars running approved software will be allowed in. Those sort of problems go from "impossible" to "almost trivial" when the exact movements of every vehicle in the tunnels is being monitored and controlled by a centralized system.

They still need to get somewhere in order to enter the system, unless you're banking into full self driving. And they need to get there at a pace of one car every two seconds, or there needs to be a buffer.

Re: Hyperloop: Pipes of Fancy

#313

Post by ashtonkem »

welterde wrote: post #306
_ph_ wrote: post #270

Earlier quoted context omitted.

Yes, he claims to have found a way to drastically reduce construction consts. First of all, reducing the tunnel diameter, as the digging speed is constrained by volume. Second, he tries to improve the technology of tunnel boring machines. With the smaller tunnels, there is the requirement for smaller vehicles. You can't run standard trains through these tunnels. For now, he is using Teslas (quite obvious choice) to d…

If I am not mistaken the boring co test tunnels are actually slightly larger in diameter than the London tube tunnels (3.8m vs 3.6m), so you could actually run "standard" trains through those.

Ah, that is a very interesting detail. A compelling argument to stop with the whole “we’re going to zip around teslas” and just promise to make subways cheaper.

Re: Hyperloop: Pipes of Fancy

#314

Post by dmitriid »

Ajedi32 wrote: post #309
liability wrote: post #297

Earlier quoted context omitted.

How many amusement parks can load a ride car once every two seconds? Even continuously moving ski lifts aren't anywhere close to that and that's basically ideal conditions where the seat is delivered straight to your butt, and most users can reasonable be expected to be fit and coordinated. In the real world, people dawdle. You'd probably need dozens of loading lanes to reach .5/s, which means the stations are very l…

You mean stations like this? https://www.boringcompany.com/chicago

>> which means the stations are very large and expensive caverns.

> You mean stations like this? https://www.boringcompany.com/chicago

Yes. This is a very large and a very expensive cavern.

Re: Hyperloop: Pipes of Fancy

#315

Post by agumonkey »

liability wrote: post #302
agumonkey wrote: post #258

Earlier quoted context omitted.

come on, have you forgot VW recent scandal ? CO2 emission was solved partially by cheating, not making EVs

You're mistaken, VW was caught cheating nitrogen oxide emission standards in America, not CO2. There have been some allegations they may also have been cheating CO2 emissions, but that's not nearly as clear and the nitrogen oxide emissions is really what the big fuss, and arrests, were about.

You have a point, although I thought NOx were a side effect of using particle filters and catalytic converter for CO2 emission reduction.

Re: Hyperloop: Pipes of Fancy

#316

Post by nick_kline »

ashtonkem wrote: post #268
andbberger wrote: post #216

Earlier quoted context omitted.

The crews can absolutely be paid all day to do nothing.

They often are already. Besides, capital costs of construction and vehicle acquisition absolutely dominates the cost of operation. The problem isn’t that running constantly available service isn’t affordable, the problem is that we lack the political will to make mass transit a meaningful alternative to cars.

I only know about Seattle where they were not paying for no work in the middle of the day. They had a last 2 mile transit van that would take you from your house to the P&R and back for a while. It was because the park and ride was filling up earlier and earlier and so people couldn't get to the bus to ride it. In this case, I know because I asked them how the pay went. They only got paid in the morning and the afternoon, there was no service and no pay in the middle of the day, only during rush hour.

The drivers I spoke to about this didn't like this because there wasn't enough time in the middle of the day to get a different job so they ended up getting a longer than 12 hour day to get 2 4 hour work periods.

Re: Hyperloop: Pipes of Fancy

#317

Post by woodandsteel »

The article presents the expert case for why hyperloop is doomed to fail. Normally in this sort of situation, I assume the experts are correct, but not in this case. Let me explain why.

The reason is that we have been in this situation several times before with a Musk idea. The experts all said it was completely crazy, but nonetheless it succeeded spectacularly.

The reason the ideas succeeded is Musk is a genius and as a consequence he thinks things out much better than the experts, who are not geniuses, do.

I am not saying that hyperloop will succeed. No one succeeds all the time, and perhaps this time Musk will fail. I am just saying it seems to me virtually certain he is quite aware of all the factors that the experts say would cause hyperloop to succeed, and has developed surprising solutions to them, and there is a good chance these solutions will succeed.

Re: Hyperloop: Pipes of Fancy

#318

Post by Robotbeat »

ashtonkem wrote: post #313
welterde wrote: post #306

Earlier quoted context omitted.

If I am not mistaken the boring co test tunnels are actually slightly larger in diameter than the London tube tunnels (3.8m vs 3.6m), so you could actually run "standard" trains through those.

Ah, that is a very interesting detail. A compelling argument to stop with the whole “we’re going to zip around teslas” and just promise to make subways cheaper.

The Boring Company And Musk said they’d be willing to make Subway tunnels, too.

Turns out Teslas are cheaper per passenger seat than a subway car plus have less requirement for specialized infrastructure (rails, etc). So if TBC is gonna be doing the whole project, they intend to use Teslas. It’s not a bad engineering choice. With automation (not hard in a tunnel), can achieve similar throughput as a Subway.

Re: Hyperloop: Pipes of Fancy

#319

Post by richardw »

ashtonkem wrote: post #265
richardw wrote: post #221

Earlier quoted context omitted.

I never mentioned bulk goods. I mentioned items that are time sensitive. Most e-commerce is latency sensitive. I recently started getting groceries on an hour delivery. It’s a game changer. Amazon could probably power a network like that by itself. What would a 2 hour Amazon delivery to most cities do? What markets does it enable access to? How do you compete with that? It’s too easy to think of why something won’t w…

> Don’t use my examples, make your own. That’s ... not how arguments work. You’ve got to provide your own examples. I’m not going to do your work for you. > Saying “no” to that question is to bet against human desires and ingenuity This is genuinely a bad way to approach these things, as you’re presuming that it’ll work based on enthusiasm and not evidence. This exact same logic would’ve led you to advocate for flyin…

I said let’s think it out. That’s an invitation to consider possibilities that might work, not a declaration that I’ve found the perfect example. Brainstorm, not argue.

But hey, argue gets your rocks off, go right ahead. Feel smarter pointing out that something very hard probably won’t work? We knew that already.

Re: Hyperloop: Pipes of Fancy

#320

Post by welterde »

Robotbeat wrote: post #318
ashtonkem wrote: post #313

Earlier quoted context omitted.

Ah, that is a very interesting detail. A compelling argument to stop with the whole “we’re going to zip around teslas” and just promise to make subways cheaper.

The Boring Company And Musk said they’d be willing to make Subway tunnels, too. Turns out Teslas are cheaper per passenger seat than a subway car plus have less requirement for specialized infrastructure (rails, etc). So if TBC is gonna be doing the whole project, they intend to use Teslas. It’s not a bad engineering choice. With automation (not hard in a tunnel), can achieve similar throughput as a Subway.

There is no way you can get even close to the same capacity as a subway.. not even for a point to point setup.

Minimum train space with pretty standard signaling can be as low as 90s. With modern moving block systems that can be pushed even lower. The tube trains have a seating capacity of around 250 people and 800 people can be standing. This gives a capacity of between 3 and 12 people per second.

How are you going to inject 1 car per second (to reach the lower level) into the tunnel in a safe way? And even if you could do it - Consider how huge the stations must be. They have to contain 100+ cars plus space to enter/exit them (couple seconds to come to a stop, 10s of seconds to leave the vehicle - with some people quicker than others -, 10s of seconds for other people to enter the vehicle, couple seconds to accelerate and synchronize to the flow..).

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