Hypnotized by Hyperloop • Hacker News Board

Re: Hypnotized by Hyperloop

#171

Post by tintor » Sun, Jul 30, 2017, 10:38 PM UTC

grecy wrote: post #167

jonstewart wrote: post #133

Earlier quoted context omitted.

One feature of classical mechanics is that the world must abide by it. With transportation, the vehicle must start and stop at a speed of zero. The energy required to accelerate the vehicle to its top speed and then decelerate it to back to zero increases quadratically as the top speed increases. Another feature of classical mechanics is, of course, that Aristotelian concept of kenophobia, or horror vacui, or resinte…

> With transportation, the vehicle must start and stop at a speed of zero. The energy required to accelerate the vehicle to its top speed and then decelerate it to back to zero increases quadratically as the top speed increases. Don't be so sure. The vehicle could move continuously at cruising speed while individual people are brought to/from it and then "dock".

Those people still have to accelerate / decelerate.

Re: Hypnotized by Hyperloop

#172

Post by dagss » Sun, Jul 30, 2017, 10:42 PM UTC

TeMPOraL wrote: post #113

Tiktaalik wrote: post #112

The vague notion of Hyperloop is awful for cities for the reasons mentioned in this article. Municipal governments are fighting a very hard, uphill battle right now to get basic funding for proven conventional public transit services which would dramatically make life better for everyone. Musk dropping the promise of Hyperloop (with no interest on following up on the idea) has provided ammo for transit cynics and opp…

One thing I don't understand about the "induced demand" thing - surely there must be a limit to this? If you keep expanding roads, at some point you must hit the situation in which your capacity is greater than the number of people even remotely interested in traveling the road... I suppose the limit might be quite high, but I've never seen it discussed at all .

The limit is very high because it is not just the current pooulation, but all the new housing that is also induced. Where people live is a functon of transportation.

Re: Hypnotized by Hyperloop

#173

Post by SOLAR_FIELDS » Sun, Jul 30, 2017, 10:53 PM UTC

rdiddly wrote: post #86

dalbasal wrote: post #18

One feature of the transport market (from a mile high view) is that demand is almost infinite. If you can get 40kms in 45 minutes, then you can live within 40 miles of work and commute in that time. If you could go 400kms, then that becomes your commuting radius. We've seen people spread this way as earlier mechanized transport was invented. IE, average commute times didn't go down because of faster transport, distan…

Transpo wonks call this "induced demand" - the component of transportation demand caused by people reacting to the availability of transportation. Every infrastructure improvement induces a certain amount of demand, including incremental ones like adding lanes to roads. It's the reason new lane additions always seem to reach a point of being congested, faster than anticipated. In this way transportation spending is b…

It's 100% observable. I used to work for a regional transportation council that made high level decisions for where to alleviate congestion. There were many hundred-million dollar projects that counterintuitively increased congestion, because the increased availability created by the infrastructure caused even more people to move to the area. After the original project was completed, decreased congestion would be observed, but 2-3 years later it would be even more congested than before the project began.

Re: Hypnotized by Hyperloop

#174

Post by eesmith » Sun, Jul 30, 2017, 10:55 PM UTC

pas wrote: post #160

eesmith wrote: post #132

Could someone tell me how these tunnels will be cooled and vented? Sure, put a car on an electric sled. But the people want A/C (or heat), and lights, the wheels provide friction. If the car was running beforehand then the engine block is cooling off. Even if it's an electric car, the brakes, tires, and skin will be hot, dumping heat into the well-insulated tunnel. This is a well-known problem in London, where decade…

You can transport heat quite efficiently in pipes (via water), it just takes a lot of money to build a cooling network. And a lot of energy to run it (both the regular and the heat pumps).

And surface area for the cooling towers, or a convenient body of water for dumping the heat.

Thinking about it some more, I believe one way to answer my question is to look at what Helsinki has done with their underground city. But their surface density is nothing like the US Eastern Seaboard, and they have perhaps one of the best places for doing an underground tunnel system, with excellent rock, cool temperatures, and easy access to the Baltic.

Re: Hypnotized by Hyperloop

#175

Post by com2kid » Sun, Jul 30, 2017, 10:58 PM UTC

jcranmer wrote: post #105

hsitz wrote: post #34

Earlier quoted context omitted.

"I am still not clear how a pod that can carry max 12 people can compete with trains that can carry hundreds." Max persons per trip seems a metric of little relevance, if a pod is much faster and can make many more trips within the same time period. In any case, that would point to how the pod could compete: carry just as many people each day, but each person would reach his/her destination much faster than if they u…

High-speed trains are dispatched around one train per hour between major city pairs, with similar or higher frequency for local trains on the same line. Even if you ignore the low-speed alternatives, you'd have to dispatch pods in the region of one per minute to achieve the same passenger throughput. Well, there's the real problem with Hyperloop. It's not really feasible to operate switches more frequently than 45-se…

> High-speed trains are dispatched around one train per hour between major city pairs,

Which seems in itself to be a huge problem.

If Hyperloop can dispatch pods at shorter intervals, then high speed transit becomes a lot more user friendly. For the same reasons buses that run every half an hour are not the solution to mass transit, but put buses out that run every 5 or 10 minutes and the usefulness shoots way up.

Re: Hypnotized by Hyperloop

#176

Post by zootam » Sun, Jul 30, 2017, 11:26 PM UTC

jcranmer wrote: post #164

pas wrote: post #157

Earlier quoted context omitted.

Only cost is important for tunnels, because there's still space sufficient for hundreds of layers of tunnels below cities.

Only if you build tunnels that no one can get to. Road tunnels still need to obey grade and (horizontal and vertical) curvature restrictions. For example, every story down you push a tunnel, every city block longer an access ramp needs to be. And the deeper you make tunnels, the more difficult ventilation and pumping becomes.

theoretically one could avoid vertical curvature issues by connecting the tunnels with large shafts, similar to elevators in skyscrapers.

Re: Hypnotized by Hyperloop

#177

Post by nickparker » Sun, Jul 30, 2017, 11:28 PM UTC

jonstewart wrote: post #133

dalbasal wrote: post #18

One feature of the transport market (from a mile high view) is that demand is almost infinite. If you can get 40kms in 45 minutes, then you can live within 40 miles of work and commute in that time. If you could go 400kms, then that becomes your commuting radius. We've seen people spread this way as earlier mechanized transport was invented. IE, average commute times didn't go down because of faster transport, distan…

One feature of classical mechanics is that the world must abide by it. With transportation, the vehicle must start and stop at a speed of zero. The energy required to accelerate the vehicle to its top speed and then decelerate it to back to zero increases quadratically as the top speed increases. Another feature of classical mechanics is, of course, that Aristotelian concept of kenophobia, or horror vacui, or resinte…

The energy required only grows quadratically if you stay on one technology.

Simultaneously switching from internal combustion to linear electric motors with efficient regen. braking and bumping the speed up 10x turns out to be a wash.

Re: Hypnotized by Hyperloop

#178

Post by isostatic » Sun, Jul 30, 2017, 11:55 PM UTC

fiatjaf wrote: post #135

isostatic wrote: post #117

Earlier quoted context omitted.

City parks wouldn't be economically beneficial, who would pay to go to a city park? Could that really justify the land use. However the fact those parks are there does make life better. Measuring that though is tricky. How much is a child's laugh worth?

You've never lived in a place without city parks.

I can't think of any city or even town without a park. The hamlet my sister lives in doesn't have a shop, but it does have a park.

The village my children go to school in has a population of about 300, no park, but it does have common open ground.

Re: Hypnotized by Hyperloop

#179

Post by logir » Mon, Jul 31, 2017, 12:01 AM UTC

maxerickson wrote: post #107

ardit33 wrote: post #27

Earlier quoted context omitted.

Yes, but it creates huge economic positive impacts 1. You can live in a less expensive area, (i.e. miles away), and work in a major center. This makes both possible of talent being able to live cheaper, and be able to work where they want (less geographical restrictions), which unlocks greater efficiency of the work place. 2. The alternative? Most people living with few tens of miles of workplaces, prices of living r…

The housing pressure from San Francisco looks like it currently extends at least as far as Gilroy to me (houses going for 1/2 million dollars). That's without it being a viable commute to the peninsula. http://www.caltrain.com/schedules/weekdaytimetable.html

It's presumably a viable commute to the south bay?

Re: Hypnotized by Hyperloop

#180

Post by zaroth » Mon, Jul 31, 2017, 12:03 AM UTC

kome wrote: post #99

methodin wrote: post #85

Earlier quoted context omitted.

It definitely seems problematic to put your entire foundation of travel in the hands of government or companies, though. They especially do not represent the concerns of all people. A car on the other hand is complete freedom. I would have expected to hear that driverless cars are the future since it's not contingent on an non-existent infrastructure, rather on the roads that already exist.

> It definitely seems problematic to put your entire foundation of travel in the hands of government (...) They especially do not represent the concerns of all people. A car, on the other hand, is complete freedom. Well, car needs roads and roads are public goods. And, of course, they need a lot of public funding, planning and maintenance. All with public money. Governments pushed for cars as a mean of transportation…

The utility of a car is hard to overstate. Our entire modern economy rests upon it. Self-driving only magnifies the awesome utility of cars even further, and will drive even more automation throughout the system.

Self-driving pickup of my groceries? Check. Self-driving pickup of my dry cleaning? Check. Self-drive me overnight to next vacation? Double check.

The future is bright, and it's chock-fucking-full of (self-driving) cars.