Hyperloop: Pipes of Fancy • Hacker News Board

Re: Hyperloop: Pipes of Fancy

#281

Post by grecy » Thu, Aug 13, 2020, 5:12 PM UTC

kwhitefoot wrote: post #255

grecy wrote: post #18

Earlier quoted context omitted.

Which is why the first Hyperloop will probably be built outside the USA. Melbourne to Sydney always seemed like a good choice to me. It's one of the busiest air routes in the world[1], there is obviously tons of solar, lots of open land beside the existing road, no seismic activity to speak of and it's a good long distance to get up to speed (~1000km). [1] (actually #3 in the world by number of passengers) https://en…

> lots of open land beside the existing road, Then you can just build a conventional 300kph high speed train and track. They are 'off the shelf' commodities these days. It will still be competitive with flying.

> It will still be competitive with flying.

Flight time is 1 hr 20 mins.

At 300kph it's going to take a high-speed train almost 3 hours.

Re: Hyperloop: Pipes of Fancy

#282

Post by bagacrap » Thu, Aug 13, 2020, 5:18 PM UTC

yodelshady wrote: post #243

For "short" ( For longer journeys, I'm not sure there's a technical case for hyperloop over a plane even with zero land cost - planes at altitude are good at what they do. The challenge a plane has in enabling those journeys is that, whilst a plane doesn't need much land in total, it needs an awful lot at the terminus. So it's a last ten miles, not a last mile. However, a good shuttle service can solve that.

it's not that planes need a lot of space, it's that many airports are ridiculously large to accommodate many planes, and far away from city centers. Those are choices made perhaps due to noise or pollution, but there are exceptions where airports are inside the city and small enough to walk from end to end, such as Burbank in Southern California. Why is there a tendency to build a few huge airports instead of smaller regional ones?

Re: Hyperloop: Pipes of Fancy

#283

Post by stevep98 » Thu, Aug 13, 2020, 6:11 PM UTC

klipt wrote: post #126

privong wrote: post #118

Earlier quoted context omitted.

> the TGV is also profitable Correct me if I’m wrong, but my impression is that this is only true if one excludes the capital costs associated with the railroad (tracks, right of way, and I think also rolling stock). If you factor in the infrastructure construction costs (and reasonable lifetimes for replacing rolling stock), a high speed trail line will never be profitable without significantly higher fare prices th…

Public transit is almost always unprofitable without some way of capturing the increased land value near the stations. Supposedly some subways (eg Hong Kong?) own the land near the stations and use the rents to fund the subway, rather than just using fares. A land value tax that goes back into public transit would probably work too.

I was told that Hong Kong metro makes more from real estate rental than ticket sales.

And just look at what we put next to our Bart stations: giant parking structures. Sigh.

Re: Hyperloop: Pipes of Fancy

#284

Post by floppiplopp » Thu, Aug 13, 2020, 6:11 PM UTC

A car salesman who talks the public into investing huge budgets into a mass transportation system that will never efficiently work and is basically a huge was of taxpayer money? Why would Elongated Muskrat do that, I wonder?

Re: Hyperloop: Pipes of Fancy

#285

Post by liability » Thu, Aug 13, 2020, 6:53 PM UTC

kanox wrote: post #188

liability wrote: post #107

Earlier quoted context omitted.

> "Can someone explain me how Hyperloop is supposed to work?" 1) Mass transit competes with cars. 2) Elon Musk sells cars. 3) High speed rail projects get derailed by people saying "but if we wait N years we could build a hyperloop instead" That's how Elon Musk intends Hyperloop to work.

This is one of the sillier Elon conspiracy theories. Tesla competes with gas cars, not trains.

Occam's Razor is sharper than Hanlon's. Elon clearly doesn't truly believe that Hyperloop could work. Hyperloop's intention being the disruption of working mass transit is the simplest explanation.

Re: Hyperloop: Pipes of Fancy

#286

Post by ponker » Thu, Aug 13, 2020, 6:54 PM UTC

notahacker wrote: post #228

ponker wrote: post #54

Earlier quoted context omitted.

It uses a much smaller tunnel.

But that's offset by it managing much lower peak passenger throughput, so you need more tunnels...

You don't need more tunnels -- you just limit your passengers to your most profitable, and make a luxury transit system rather than a mass transit system.

This is what Tesla did by starting with the Tesla Roadster then Model S then Model 3... and it's what the Hyperloop aims to do. Launch as a small throughput luxury product and if it's profitable then it doesn't matter if it ever expands beyond that or not.

Re: Hyperloop: Pipes of Fancy

#287

Post by masswerk » Thu, Aug 13, 2020, 6:58 PM UTC

johnwalkr wrote: post #248

masswerk wrote: post #88

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…

No problem, 2.5G was mentioned as an acceptable value for experienced acceleration. Do you like roller coasters?

It's about roll counteracting the parallelogram of (lateral) forces and resulting orientation in space, not linear acceleration.

Re: Hyperloop: Pipes of Fancy

#288

Post by Ajedi32 » Thu, Aug 13, 2020, 7:02 PM UTC

sudosysgen wrote: post #122

Ajedi32 wrote: post #119

Earlier quoted context omitted.

That's still 2 to 7 minutes longer than a Loop tunnel. And that also only addresses half of the GP's comment (scheduling).

Yep, except that in order to match the capacity of the Montreal metro system you would need to have a car departing every 2 seconds, which is impossible.

One car every 2 seconds sounds totally plausible. In fact, that number actually seems pretty low to me. A single lane/tunnel should be able to handle automated cars traveling at a 2-second following distance no problem, so that just leaves loading/unloading as a potential bottleneck. How many on-ramps do you think it would take to reach a capacity of 0.5 cars/second? I'm really curious as to what sort of problems you're envisioning which would make that "impossible".

Re: Hyperloop: Pipes of Fancy

#289

Post by liability » Thu, Aug 13, 2020, 7:02 PM UTC

jbay808 wrote: post #163

Robotbeat wrote: post #151

Earlier quoted context omitted.

There are multiple ways to solve this problem. It’s not a showstopper. 1) Bury the lines. Basically isothermal at depth. 2) insulate the tube and maintain stable temperature 3) use materials that don’t drastically change length with temperature 3) allow the tubes to change length. Put them on rollers. 4) use vacuum expansion joints just like us common in vacuum engineering. People act like vacuum is this new thing. P…

Good point. A little hyperloop is nothing compared with CERN.

It's puzzling how you could get this so backwards. Just how big do you think CERN is? Or are you comparing to to the 'Hyperloop test tracks which are mere hundreds of meters long and have enough problems already?

Re: Hyperloop: Pipes of Fancy

#290

Post by dongvsascript » Thu, Aug 13, 2020, 7:15 PM UTC

privong wrote: post #118

owenversteeg wrote: post #47

Earlier quoted context omitted.

That "Gadgetbahn" article is great, but I do have one criticism. From the article: "If the idea is viable and the people behind it are competent, it should have attracted private investment, as there should be a potential to make profit selling the technology. After all, the proposal has been around for 23 years." High speed rail on a large scale is really something that has to come from the government. While there a…

> the TGV is also profitable Correct me if I’m wrong, but my impression is that this is only true if one excludes the capital costs associated with the railroad (tracks, right of way, and I think also rolling stock). If you factor in the infrastructure construction costs (and reasonable lifetimes for replacing rolling stock), a high speed trail line will never be profitable without significantly higher fare prices th…

libed there a bit and have this to say: to cover thise extra costs, they would have to charge a ridiculous amount per ticket. like double the cost if a flight to those destinations. and they do. $300 for a 5 hour train ride. so i can totally see this being profitable all costs uncluded.

here's why i think they get customers. people don't like airports and plane travel, so they'll pay more for rail. car travel is unpleasant. cars are tiny and uncomfortable. their tolls are insane. like $50 in tolls for that same drive. less people have cars, and getting an license is a big expensive thing. they don't do roadtrips.