Their baseline optimization focuses on 5 subsystems: Compressor Cycle Analysis, Pod Geometry, Tube Flow Limitations, Tube Wall Temperature, and Mission Analysis
Initial results indicate that the concept is still very viable. However, due to very tight coupling between the tube and vehicle size, the tube size will need to be around twice as large as originally proposed by the Tesla/SpaceX team to reach the proposed speeds.
Feel free to download the entire analysis and play with it yourself, without purchasing several expensive toolboxes from MATLAB!
As one of the authors of this work, I would like to add that our goal was to provide an open source foundation for modeling the hyperloop system. Our initial work focused on the pod itself, but we want to expand it to include trajectory analysis as well as cost modeling.
I remember hearing an interview with a civil engineer about why highways have all these "unnecessary" curves in them. Why can't engineers build highways that are more direct and straight?
After going on a bit about requirements for different kinds of terrain, the kind of strata the road needs to go on etc. and how those were difficult and expensive to surmount (so curves were often chosen to deal with it instead of a more expensive solution). He lamented that the most difficult and expensive aspect of new road construction was right of way through existing developments and other properties. Most of the curves we experience on highways are apparently the result of somebody, or a block of people, simply not wanting to give up their land.
Fatigue, boredom, and monotony are a factor, too. I watched an episode of Modern Marvels on the History Channel  which gave interesting details about the highway system. They mentioned something they called "highway hypnosis" , a trance-like state which they wanted to avoid. There's been some discussion of whether this phenomenon is to blame for the train derailment in New York about a month ago .
Most of the curves we experience on highways are apparently the result of somebody, or a block of people, simply not wanting to give up their land.
Nor should they have to, if they don't want to (or disagree on the price).
>Nor should they have to, if they don't want to (or disagree on the price).
This is a real issue in many places now; when building a transportation system the government should be able to pay you whatever the house is valued and give you no saying on that, why? because the mobility of millions is more important than your emotional attachment to the house.
I don't know how it actually works, but I would hope if the government uses its right to force you to sell your land, which the US (and likely others) does have under eminent domain, that they would pay above market price. Market price would cover the cost of you purchasing an equivelent home, it would not compensate you for moving expenses, time, possible lost wages, ETC.
The government's "market prices" and the real value of a property are two totally different things. There is downward pressure to keep the government assessments low due to property taxes. Where I live, for example, the prices are generally off by a good -10% to -20%. Then you have to add interest, closing costs, escrow, and establishment of utilities on top of that.
You also have to factor mobility into the equation. If I own property that I'm using for a special purpose (let's use an extreme example of a hazardous chemical disposal company), and I'm told to relocate for the "market price" of my property, then I'm stuck paying tons of money and dealing with regulatory hell in whatever I choose as my new jurisdiction to do this. This would quite literally put me out of business due to the insanely high cost of relocating everything.
Also, you have the legal roadblocks that often come up (this is the more common reason property can't be acquired). For example, the property might be owned by a trust, which was granted it's powers through a will. Since it's a trust, the beneficiaries are unknown. The person who maintains the trust isn't returning your calls. Who do you write the check to? You can't just take it from the trust, it doesn't work that way (for good reason, without getting into specifics). There are ways to go about it, but the legal proceedings can take years. We're actually dealing with this exact problem now trying to expand an intersection in my local town.
Unfortunately, it's not as simple as just buying the land/structure and moving the occupants. More often than not, there's a reason why this is difficult.
It seems like the price of the various measures that avoid invoking eminent domain ends up being so extraordinarily high (hundred-million-dollar bridge trusses and the like), I do not quite understand why offering market plus 100% or something isn't a solution. Not an extortionate rate, but one sufficient to make it a financially favored course of action for all involved landowners. Eminent domain is for the irrational holdouts, not for "offering pennies on the dollar" as opponents say, or for getting just-slightly-submarket-prices.
The problem is that the only people who can say how much money is necessary is the landowners themselves. However, they have an incentive to lie if doing so would allow them to get a higher price. Additionally, different landowners would value their own land at a significantly different rate relative to the market. For example, if you live in a custom built house, with a treehouse that your kids built themselves, that is within walking distance to the school and your place of work, you would need significantly more compensation them most people to move out of your house. I don't see any solution other than letting cases where an agreement cannot be reached go to court.
Eh? That list isn't ordered, so it's not clear what you mean by 'first'. The nine cities on the list are Hong Kong, Seoul, Singapore, London, Paris, Madrid, New York, Tokyo, and Guangzhou. Six of those are in fully operational democracies, two are in incompletely democratic but non-brutal post-colonial city-states, and one is in China.
What's really not surprising, of course, is that over half of them are in cities built by the British!
Eh? When I said the first I mean like... the first; not in a ranking system but in a left-to-right top-to-down standard English reading way.
Yeah; if by the British you mean actually the Honk-kong government that is the creator of the MTRCL, the company that build the system during 1979 -which helped them to receive a little bit of land- and became a private company in the year 2000.
Most of them weren't created by the British; who creates the rail system is the one that matters, not who "creates the city".
And the fact that so few of them are in America despite being bigger than all the other countries in the list (maybe even combined) and that so many of them are in Asia should help emphasize my point a bit because cultural aspects are also in play
American: Government wants my land to build a subway? Jackpot! I better give it a high valuation to squish as much money from them as I can; they screw my with taxes now I will screw them!.
Asian: The Government wants my land to build the metro system and they even will give me money for it? It's such an honor to be able to serve my community and all our generations to come with my little property.
why? because the mobility of millions is more important than your emotional attachment to the house.
Even if you accept that principle -- and while it's not unreasonable, I can also see reasonable arguments against it -- where does this policy end?
Let's get an idea of scale here. The entire UK national rail network currently supports approximately 1.5 billion passenger journeys per year. If we make some plausible assumptions about regular commuters, then probably 5-10 million individuals benefit from travelling on the rail network's approximately 10,000 miles of track more than occasionally. In other words, when you're talking about the mobility of millions, you're not really talking about building a small part of transport infrastructure that affects the property of a few unfortunate people, you're talking about building the kind of infrastructure that supports a population of 60+ million and gets built over many decades.
Let's also consider the likely alternatives. Major projects like new rail don't just affect a few square metres of someone's land when they pass through. Again picking on the UK, just because we have lots of conveniently available data about the new HS2 proposal, the government is now safeguarding an area 60m either side of the proposed route (for the first stage) so strongly that you basically can't do anything in that zone in terms of planning permissions. Obviously in terms of noise and potential disruption to local infrastructure and local travel arrangements, the effects of a major high speed rail link go far more than 60m from the track. So this isn't the kind of project where a single person with a 3-bedroom house is going to be throwing the spanner in the works. It's the kind of thing where an entire rural community is probably under pressure, or within cities with dense accommodation, potentially hundreds of residents in a single building, multiplied out by several buildings. The alternatives that avoid these problems don't just put a slight kink in the proposed route, they probably adjust the route over several miles to go around the entire area, or they relocate the routes and stations within the city so the new path isn't so disruptive, and maybe adjust the local transport infrastructure around stations to support this.
So, your idea of the mobility of millions vs a bit of emotional attachment to a house is not really what we're likely to be talking about for any single infrastructure project. What about some numbers on a more realistic scale? Does the convenience of 10,000s of people having a station a little closer to their office in the centre of the city so they can save two minutes of walking to work every day outweigh the inconvenience to 100s or 1,000s of people whose homes must be destroyed to make way or whose communities are split down the middle by the new route? Does saving a minute or two on a cross-country journey lasting hours outweigh destroying an entire community whose rural settlement is in the way? These are the kinds of argument that compulsory purchase/eminent domain really tends to raise, and they aren't nearly as one-sided as your comment about the mobility of millions might suggest.
Yeah; you are pretty one-sided too when the example you use is "the convenience of 10.000s of people having a station a little closer" and not something along the lines of "the difference between a straight route rather than two curves on it resulting in adding 30 minutes to the traveling of every person that uses that route now, and in the centuries to come"
That example also shows why "millions" is not an understatement.
"the convenience of 10.000s of people having a station a little closer"
If the estimates that the Hyperloop would carry in the region of 3,000 passengers (either way) per hour are correct, calling it 10,000s seems reasonable.
Indeed, it seems quite plausible that constructing something like the currently proposed Hyperloop would cause severe disruption to more people than would actually save a little time travelling on it in a year. Over its entire working lifetime, the number of person-hours lost because of construction effects might still heavily outweigh the number of person-hours saved because of marginally reduced journey times.
"the difference between a straight route rather than two curves on it resulting in adding 30 minutes to the traveling of every person that uses that route now, and in the centuries to come"
I didn't give that example because nothing we're talking about for either Hyperloop or the UK-based rail network is anything close to adding 30 minutes to the journey time. You're absurdly exaggerating the effects of rerouting. Maybe if you added numerous deviations to avoid numerous undesirable land conflicts you'd get to that kind of level, but in that case you have to balance it against numerous different sets of people who lose out in all those conflicts as well.
Basically, the idea of claiming large amounts of land where people are living right now to build infrastructure like the Hyperloop is about as blatant an elitist land-grab as I can think of. If it really were severely inconveniencing a handful of people to make life significantly better for millions you might at least have a decent argument, but the real numbers don't appear to be anything like that from any of the Googling I'm doing today.
You must be bad at googling then, because the current transportation system of SF, the BART system, carries 373,945 people in average... per day!
It was just an example and I was referring to the appropriation problem not specific in this case; but even if you want to stick with this one you can see that the suggestion of the analysis is to build the hiperloop along the freeway; unfortunately many high density cities don't have one already.
Well, some napkin math: The current system travels at 110 km/h and the Hiperloop goes in a low-estimate average of 350 km/h, so it would save at least two thirds of the current time, if each one travels just 20 minutes using the BART system then let's say 190.000 people that would use the Hyperloop (instead of BART) would save 36932 years of time lost in the next 20 years (with assuming no increase in population, which is false), if it takes 10 years to be build and adds 5 minutes to the time of every car passenger (because it doesn't disrupt BART operation) and SF traffic is pretty good (meaning very low), and if SF moves ~270K cars daily and assuming one passenger it would mean 540K people so it would mean 18750 years lost. But one single lifetime is usually longer than 10 years so most of the people losing time now will be part of the people saving time later thanks to the Hyperloop. So even accounting for the time lost -in a rough estimate- people would save half the time they spend now traveling.
Many things I did not even take in account:
- This will not disrupt car because if you can take the Hyperloop and arrive in 15 minutes while you play Angrybirds or use you car but take 30 minutes you would likely choose the former every time (not just sometimes).
- Less Time save lives; if you are bleeding from a gun shoot arriving 10 minutes faster is the difference between life and death so it saved the rest of your lifetime.
We seem to be talking about completely different things here. Where did this reference to BART and carrying 300,000-400,000 passengers daily come from? How is that local transport system anything like long-distance, high-speed infrastructure like the proposed Hyperloop system? They're completely different types of transportation, so your hypothetical scenario where one is somehow replaced by the other makes no sense. And how on earth did we get from talking about compulsory purchase/eminent domain to secure land for that kind of long-distance transport infrastructure over to talking about something to do with cars?
Even if we had been talking about BART, to build a new system like that today, with around 100 miles of track and dozens of stations in urban/suburban areas, you'd have to buy up huge amounts of formerly residential land if the area was already well-developed. That would inevitably displace many thousands of people who previously lived there, as well as divide and blight the communities that remained. The social and economic costs of forcing a new system like that on a mature city would be staggering, and it would be likely that much of any new system would be built underground to avoid the damage on the surface.
If you can make a 1000 km straight road somewhere in Nevada, it'll be cheaper and more efficient to do exactly that. Neither drivers nor investors would like increased travel time and costs because of the fatigue and boredom. The real improvement would be to make wider lanes and allow driving 200 mph. Or even better, put a high-speed train or a hyperloop.
60 mph is not safe on narrow streets of Paris either. Does it mean 60 mph should not be allowed where it's safe?
If you have wider lanes, more lanes, better tarmac and smooth road with safety lanes, people can drive 150 mph without a problem. Like in Germany, for instance. If the road is not safe for 150 mph, then you should drive slower.
Geez I remember my dad's Toyota Camry would start shaking at just 140 km/hr (87.5 mph.. holy crap maybe I was about to time travel). Many cars, and especially most drivers, just can't go that fast safely..
My first car (an '87 Subaru DL, which I had in 2000-2002 IIRC) started shaking between 70 and 75 MPH. My parents regarded this as a feature, because as a new driver I really had no business going faster than that. They were probably right.
Right, why shouldn't people give up their homes and businesses to make this guy's job easier? Talk about a sense of entitlement! The truth is in a civilized society the interests of different groups of people must be accommodated. Next time it might be your house they want to flatten so people from one place you've never been can get to another place you've never been one minute quicker.
Because, it is not really their land. If they are paying property taxes to anyone, or other taxes based on it, or rent , it is not theirs. The hammer that I bought at Home Depot is mine. Nobody can come and take my hammer away after I paid money for it.
Nevada has tried allodial titles but they are largely a sham you basically pay your property taxes ahead, and yes, you can win if you start developing the land quickly, and then don't get into an accident and die somehow.
Basically, the land belongs to those who have the military power to defend it from others who might come and take it. Then that owner leases /doles/rents/sets-up-a-title-system+tax to whoever it wants. This is not different from the Medieval times. It is just wrapped in nice (or not so nice) laws and terms and so on, but at the bottom it is what it always was.
So in some state or countries, government can and will take your land away. Sometimes it will let other come and extract natural resources from it. In some places it will take it and give it to bigger companies to build malls or factories.
> to make this guy's job easier?
The road is not built for this guy to use, it is built for everyone else to use. One can turn that question on its head and say why can't all the citizens drive in a nice straight direct way saving time, gas, money because someone's farm is in the way? Talk about a sense of entitlement...
Guess what. Someone with an army can come and take away your hammer as well. That money you got paid last month, someone can tax that too.
Things aren't perfect but I think individuals (in-duh-viduals :-) ) have more power than ever.
I'm also not sure that making straighter roads is the most important problem facing humanity. More often than not, governments will take that farm in the way (and they just did this over here in British Columbia for a new road they've built). The sense of entitlement is really that guy out in the suburbs who thinks it's his god given right to drive his SUV to the city every day on the straight or not so straight road and the people who want that cheap piece of plastic from China in their local shop driven by trucks on some straight or not so straight road...
> Guess what. Someone with an army can come and take away your hammer as well
It is true but at least there is no legal cover and language that make me think that I "own" it while I really don't. They would have to march in, beat me up and take my hammer. It would be rather unambiguous what is happening. Land "ownership" doesn't work that way. There are enough legal ways for one to be deprived of the "owned" piece of land.
Property taxes, land ownership is veiling in "ownership" language but in reality to me it seems if you have to pay someone yearly "rent" for it then you don't really own it.
> The sense of entitlement is really that guy out in the suburbs who thinks it's his god given right to drive his SUV to the city every day on the straight or not so straight road
Alright, what if the road was a bike path? Would that make it better ;-)
The general argument is whether something that is a public good should trump the needs of land owners. And I was just pointing out there are a few hairy details the way I see it.
It's the difference between "ownership in fee simple" and a "freehold lease" or "freehold tenancy". I'm not aware of any ownership in fee simple in the US or Canada; it's usually the sort of thing that a Marquess or Duke has in a feudal sort of arrangement (you own the land outright rather than merely at the pleasure of the sovereign, be that a monarch or The People writ large, but you're required to defend it in turn). Smaller fee simple properties exist in England as well, often as the result of the grant of peerage in ye olde dayes (the Norman and Angevin periods mostly). For the most part, though, in the english-descended world, the most you can have in a property is freehold tenancy.
I believe you're creating a distinction that doesn't exist. What is the difference, in your mind, between a hammer or other object being seized by authorities and a piece of real estate being seized by authorities?
Your perspective seems very specific to California's tax structure. I wonder how you incorporate "use tax" into your theories.
> What is the difference, in your mind, between a hammer or other object being seized by authorities and a piece of real estate being seized by authorities?
The distinction is that to seize my hammer they would have to turn violent, attack, assault or threaten. In that whoever did this would basically expose what is really at the heart of the issue. With land there is a legal framework to disguise pretty much the same thing but using "ownership" language. In reality, to me it seems, it is not much different or not much different from land owners in medieval times giving land to their subjects.
> Your perspective seems very specific to California's tax structure.
I think it pertains to most states in this country. I don't know of many states that don't charge property taxes. Most countries have something similar.
In Great Britain (from what I understand from marginal discussions I've had) this is more obvious. All land belongs to the Crown and it doles it out to tenants who dole it out to sub-tenants and so on. These are often Lords and Ladies from medieval times and their heirs still collect "taxes" based on that ownership.
The exact same force is used in seizing a hammer or other object as in seizing a house. In both cases law enforcement will eventually arrest you, put handcuffs on you and take you to jail if you do not comply.
I mentioned the use tax, and that California does not have one. Do you know what a use tax is?
>>The general argument is whether something that is a public good should trump the needs of land owners.
You talk like there are these super wealthy land lords with nearly unaccountable real estate not willing to yield an inch.
The reality is, its some ones home. Just like I and you have. If you are destroying that, you better pay up good compensation. Which in most cases never paid. In my country(India) compensation paid is some thing like 5% of the actual land value.
Imagine some one just walking up to your home in full police gear, bulldozers and then just asking you to leave or get killed in the process of demolition. They will have the necessary legal documents and police support. You will be given some peanuts while you watch your property razed to ground. All in the name of 'public good'.
In New Delhi, the son of a judge used his connections to first acquire a land to build a mall inside a area which had very narrow roads. He built the mall, then figures out no one wants to visit the mall due traffic and parking problems. Guess what he does next? He further bribes officials and gets them to demolish a lot of homes to broaden roads, so that traffic and parking issues go away to help his real estate grow.
There was a massive uproar, as to how the whole system works. The supreme court of India, has now said no land can be acquired unless the owners of the land give a explicit permission and agree that fair compensation has been paid.
> You talk like there are these super wealthy land lords with nearly unaccountable real estate not willing to yield an inch.
You talk like they are not. My hypothetical people in front of the future straight highway are richer than your hypothetical people in front of your hypothetical highway. I set up my hypothetical situation the way I want, sorry ;-)
> The reality is, its some ones home. Just like I and you have.
We have a home? That is still more than a lot of people have.
> Imagine some one just walking up to your home in full police gear, bulldozers and then just asking you to leave or get killed in the process of demolition. They will have the necessary legal documents and police support.
Ok, imagining that. Wasn't that my point? One doesn't really own the land unless they can defend it from violence. You'd have to be a country with military in order to have a proper allodial title. In countries with lots of corruption the abuse is worse, I can see that, it is obvious. I was pointing out that even in "law abiding" countries that law is written to hide the underlying brutal fact that people don't really "own" the land. Someone else owns it and they just pay rent (disguised as "property taxes" in our case).
> He further bribes officials and gets them to demolish a lot of homes to broaden roads, so that traffic and parking issues go away to help his real estate grow.
Well there are 2 issues. Bribery and corruption and taking from people to build roads. Well the first one seems more pressing. It covers all areas of life not just imminent domain.
> All in the name of 'public good'.
Isn't there or shouldn't there be a 'public good'? What is your alternative to say everyone just building on top of all the public roads that access the city so there is simply no way to enter or exit the city because there are buildings in the middle of the road? Is that acceptable.
>>Isn't there or shouldn't there be a 'public good'?
Yes, but why does that always have to be at some one else's expense or by making some one suffer?
>>What is your alternative to say everyone just building on top of all the public roads that access the city so there is simply no way to enter or exit the city because there are buildings in the middle of the road?
Sound city planning.
It doesn't take much to make this happen. In my city atleast(Bangalore), I can tell you so many areas of the city that are developing even now don't have sound planning. Its totally reckless, and chaotic at its best. Absolutely no space for public parks, lots of open drains, narrow roads, badly planned water supply and sewage lines.
If you know for sure something is really going to grow, you might as well plan for it. Nothing really prevents governments from enforcing regulations even for private builders.
When your money is stored in "your" bank account, or "your" mutual fund ... do you really own it?
This is where contract law comes into play, to protect vulnerable citizens from large entities with good or bad intentions. You are correct that how / whether such contracts are honored and the legal system is fair is quite variable from country to country.
It's not about making the engineer's job easier. It's about the millions of man hours that will be lost over the lifetime of the road, and the additional safety issues that arise because the road has unnecessary turns.
As we're also seeing with this project, roads are not just for cars. The pre-negotiated right-of-way is also used for utilities, mass-transit and who knows what else in the future? It has negative effects on safety, the economy, work efficiency and other factors.
Because somebody doesn't want to be inconvenienced by a move that they'll have years of notice to make, or some farm doesn't want to shave off some fraction of their road-side property, lives will be lost, work will be wasted, pollution will increase, maintenance costs on keeping the roads and other right-of-way inhabitants will be magnified and more.
A new road isn't about just going someplace you've never been a minute quicker. Most roads are about making the time it takes from getting to a place I already go faster or at higher capacity. It drives development, decentralizes and spreads around economic activity, increases national productive output, stimulates the economy, it can increase educational and employment opportunities, make consumers of productive output more accessible and efficient to reach. A good road can be the difference between abject poverty for a region, or a new city.
In some cases, what you say is true. In some cases not. I don't know if anyone actually had their land seized to build any of these http://www.bbc.co.uk/news/magazine-18855961 but shouldn't the land now be returned to its rightful owners?
If you are in the UK, consider the debate raging over HS2, or the Heathrow expansion.
True. In some places, they overbuild and seize property for reasons other than the natural expansion of the population. Japan is notorious for growing GDP through endless useless road construction and river paving, often at the expense of local landowners.
Its more about bandwidth and you know it. The system needs to transport thousands of people per hour, and Hyperloop (as designed) only has 40 pods carrying only 28 people each.
We're looking at a (theoretical) $8 Billion system... that is probably grossly underestimating costs at that... that can only support 1120 passengers at a time, max. On the entire system.
Hyperloop may be fast, but it transports very very few people. A single-train will transport more people. Frankly, when looking at mass-transit, the #1 concern is moving people, lots of people and quickly.
Just like people today care about the "bandwidth" of their internet connections, I guarantee you that city planners are more interested in the "bandwidth" of a high-speed system.
The Hyperloop, if it were possible, would have about three times the current capacity of the Acela.
At an 80min round trip running 20hr a day that's 15 trips per pod per day. So we have 40x28x15 = 16,800 daily round trips.
The Acela holds 360 people per train with 16 round trips per day. That's 360x16 = 5,760 daily round trips.
A high-speed system with dedicated track could run more often, and you could use longer trains than the Acela does, so the potential maximum bandwidth of high-speed rail is higher. But 16,800 daily round trips is large enough to be taken seriously.
Acela is the elite service for the northeast corridor. It isn't your typical consumer train, but more like the "business class" train. You get more leg room and space to move about. Of the 8 trains on Acela, two are engines, and one is a cafe car. Acela shares its tracks with the Northeast Regional system, which is what your typical consumer is going to take.
Really, Hyperloop needs to be compared against the entire Northeast Corridor... a single rail-line between Washington DC and Boston... but this single-rail serves many many more trains than just the Acela.
Or at very least, the comparison needs to be against Northeast Regional, a much slower train but is the one that your typical consumer is going to take. After all, Acela trains share its tracks with Northeast Regional... and most people prefer the cheaper prices.
The typical consumer doesn't take the Northeast Regional or the Acela. People take Airplanes for speed, or cars/buses for cost. The Hyperloop, as proposed, would compete primarily with airplanes because it's so much faster than other ways of getting between those two cities.
(Between Boston and NYC, the link I'd most likely take, the Acela is only marginally faster than the Regional. The improvements planned in CT look like they would help, but actually cut similar amounts of time off the two routes.)
I call Northeast Regional "much slower" because its top speed is slower than the Acela. But at the end of the day, I think it ends up only being a 30 minute difference, because rarely do the trains actually go at their top speed (especially as they near NYC).
IIRC, Northeast Regional is considered to be at capacity around NYC (where it services on the order of 100,000+ daily commutes).
Anyway, the reason why this is being compared to railroads, is that the investment here is not measured only in dollars. When you build ground-based transportation of any kind, it necessitates blowing over some people's property... period. That is a real cost in people's livelihood, as the government forces people to move out of their homes to make room for the new road / railroad / hyperloop.
So when we're talking about an entire "Hyperloop" system that can only service ~16k / day in theory (and probably much much less in practice), these numbers have to be weighed against the costs.
True, both Railroads and Hyperloop suffer from this problem. But I bet you that the proposed California rail system will have significantly higher capacity... especially when the Rail system is going to connect up to the local metro systems.
In fact, the High-speed rail system goes directly to Union Station in the heart of LA. Hyperloop doesn't have such plans.
Airplanes are magic stuff though, because they don't have these costs associated with them, and in practice Rail isn't much more efficient than Airplanes anyway. But the airways are crowding up between the cities, so building alternative means of travel is necessary now.
We have a better idea of what the high-speed train is going to cost than Hyperloop however.
When you have two garbage estimates, you cannot compare the two systems. The solution is to ignore the bad estimates, and recalculate the costs more realistically.
The fact that Hyperloop is modeled as a three-pylon design, and totally ignores some basic physics (such as Thermal Expansion: http://www.leancrew.com/all-this/2013/08/hyperloop/). So it is clear that the Hyperloop cost numbers are just straight up irrelevant garbage.
Granted, that is to be expected from an unbuilt, untested system. So I don't want to hate on Musk on this one. The nature of proposing an experimental design is that you won't have good data on it: costs, problems, theory... etc. etc. No one really knows how Hyperloop will _really_ work.
The benefit of High Speed Rail is that the systems have been built around the world. They have a better grasp of how much it is going to cost by nature of building their systems in other locations... and having experience with the problem.
That's really neat. Thanks for posting the link. Regarding the parent post about Edith Macefield, that's a neat story, too. It doesn't always turn out that way ... in Asia, there are many homes which have been cut off from all services (water, electric, sewer) and then the actual land is removed such that the occupants can barely get in or out of the house. "Nail house" is what they call it in China.
Hmmm; maybe in some parts of the world. Around here (NH/VT) the curves are pretty obviously imposed by geology (if they didn’t follow narrow valleys, they would constantly be going up and down 1-2k ft ridges, and river valleys are not straight).
There is the concept of eminent domain which lets the government force-purchase land for this purpose. However it's typically only done in cities or where the geography / geology requires it. Out in California's central valley where it is flat as far as the eye can see, it's sometimes better politically to do a curve to follow edges of property lines than to piss off some big wig ranchers.
And this is what Japan does to build high speed rail in a mountainous country where all the land that's possible to grow or build on is already owned. On some Shinkansen routes you spend half your time going in an out of tunnels
My hometown in Indonesia has a lot of such unnecessary merging and widening. And they are because some guys don't want to sell their land / the government not offering them enough money (depending on whose side you're on)
Passengers are much more sensitive to vertical acceleration than horizontal. Repeated 1g swings from -0.5 to 0.5 g would make this thing a vomit comet. Would be interesting to see this analysis done with normal limits for high speed rail design, instead of Elon's chosen 0.5g limit.
Edit: HS2 in Britain, for instance, is being designed with a maximum of around 0.01g vertical acceleration. If Elon's has figured out how to get passengers to handle 50x that much, he could save them a lot of money.
Vertical acceleration refers to acceleration in the direction of the tracks, right?
Some other figures I could find:
Shinkansen: 2.6 km/h/s = 0.07g
ICE (German HSR): 0.5 m/s2 = 0.05g
S-Bahn (metro transport): 1 m/s2 = 0.1g
Makes sense that metro transport has higher acceleration, as high speed rail spends a lot of time "cruising" at certain speeds, while metro transport is basically always either accelerating or decelerating. I'd guess subways also feature relatively high g-forces.
It would, but not for the reason you think: lying on your back activates the mechanism you still have from when you were a baby that stopped you getting motion sickness when you were being carried by your mother. We advise people suffering from seasickness that one thing they can do is lie on their backs, and it often is enough by itself.
Is there a source for left/right acceleration being more comfortable than down? My subjective/uneducated guess would actually be that acceleration is most comfortable in the order of: forwards, up, backwards, left/right, down.
Include that in the calculations. There's a certain absolute sideways g-force (decreasable by slowing or straightening), and a certain absolute downwards gravity. These add up to a single total force. So long as the magnitude is at least 1g, there exists a seat orientation such that the passenger feels 1g toward the seat and something on the back.
How much you can spin the seat without those movements causing problems is an open question.
Airplanes are an encouraging precedent. They often make quite sharp turns at extremely high velocity, but tilt into them such that there's almost no perceived lateral acceleration.
However from the article chart, there would be more than 50 peaks at +/-0.5G in 35 minutes, that would definitely feel more like a huge roller coaster ride than anything else, so my bet is that it's just unbearable except for astronauts and fighter pilots.
Quoting from the Hyperloop alpha paper: "To further reduce the inertial acceleration experienced by passengers, the capsule and/or tube will incorporate a mechanism that will allow a degree of ‘banking’."
A banked turn transforms lateral acceleration into vertical within the passengers' frame of reference.
Okay, sure. But that's not anything analyzed by the article at the top of this thread. And further:
1. Presumably, if lateral acceleration proves to be preferable to vertical acceleration, you just turn off the banking.
2. You control the precise amount of vertical acceleration by the size of the bank, so if there's some amount of vertical acceleration that's desired and some that isn't, you only bank hard enough for the desired acceleration. You also to at least some degree control the jerk (change in acceleration) so you can smoothly slide into the acceleration change as you bank slowly harder.
3. Importantly, this is only increased-acceleration in local "down," not decreased acceleration in local down. I don't have any scientific data to back this up, but it's the drops (ie, reduced vertical acceleration compared to gravity) that seem to nauseate people on roller coasters, not the climbs.
But most importantly, I think that people were badly misinterpreting this article (not the original hyperloop paper) in thinking that its charts were about vertical rather than lateral and longitudinal acceleration.
In a car max lateral acceleration is typically 0.3g for safety and 0.2g for comfort I think (and usually road design are even more conservatory).
I think 0.5g lateral is way to high, especially if you can't look at the outside. People are gonna puke or going crazy from the discomfort. Probably < 0.1 might be a good target, maybe even < 0.05g
Maybe the capsule should rotate during turns so that most lateral translation is translated to vertical (like in most trains at nominal speed).