Hyperloop Freight is a Joke
As the ongoing attempt to build a Hyperloop tube in California is crashing due to entirely foreseen technical problems, the company trying to raise capital for the project, Hyperloop One, is looking at other possibilities in order to save face. A few come from other passenger routes: Stockholm-Helsinki is one option, and another is the Dubai-Abu Dhabi, which looks like it may happen thanks to the regime’s indifference to financial prudence. Those plans aren’t any better or worse than the original idea to build it in California. But as part of their refusal to admit failure, the planners are trying to branch into express freight service. Hyperloop freight is especially egregious, in a way that’s interesting not only as a way of pointing out that tech entrepreneurs don’t always know what they’re doing, but also because of its implications for freight service on conventional high-speed rail.
First, let’s go back to my most quoted line on Hyperloop. In 2013 I called it a barf ride, because the plan would subject passengers to high acceleration forces, about 5 m/s^2 (conventional rail tops at 1.5 m/s^2, and a plane takes off at 3-4 m/s^2). This is actually worse for freight than for passengers, which is why the speed limits on curves are lower for freight trains than for passenger trains: as always, see Martin Lindahl’s thesis for relevant European standards. Freight does not barf, but it does shift, potentially dangerously; air freight is packed tightly in small pellets. Existing freight trains are also almost invariably heavier than passenger trains, and the heavier axle loads make high cant deficiency more difficult, as the added weight pounds the outer rail.
Another potential problem is cant. Normally, canting the tracks provides free sideways acceleration: provided the cant can be maintained, no component of the train or tracks feels the extra force. Cant deficiency, in contrast, is always felt by the tracks and the frame of the train; tilting reduces the force felt in the interior of the train, but not on the frame or in the track. At Hyperloop’s proposed speed and curve radius, getting to 5 m/s^2 force felt in the interior of the train, toward the floor, requires extensive canting. Unfortunately, this means the weight vector would point sideways rather than down, which the lightweight elevated tube structure would transmit to concrete pylons, which have high compressible strength but low tensile strength. This restricts any such system to carrying only very lightweight cargo, of mass comparable to that of passengers. This is less relevant to conventional high-speed rail and even maglev, which use more massive elevated structures, but conversely the problem of high forces on the outer rail ensures cant deficiency must be kept low.
Taken together, this means that high-speed freight can’t be of the same type as regular freight. Hyperloop One, to its credit, understands this. The managers are furiously trying to find freight – any kind of freight – that can economically fit. This has to involve materials with a high ratio of value to mass, for example perishable food, jewelry, and mail. SNCF ran dedicated TGV mail trains for 31 years, but decided to discontinue the service last year, in the context of declining mail volumes.
High-speed freight has a last mile problem. Whereas high-speed passenger service benefits from concentration of intercity destinations near the center of the city or a handful of tourist attractions, high-speed freight service has to reach the entire region to be viable. Freight trains today are designed with trucks for last-mile distribution; starting in the 1910s, industry dispersed away from waterfronts and railyards. The combination of trucks and electrification led to a form of factory building that is land-intensive and usually not found in expensive areas. Retail is more centralized than industry, but urban supermarkets remain local, and suburban ones are either local or auto-oriented hypermarkets. Even urban shopping malls as in Singapore are designed around truck delivery. The result is that high-speed freight must always contend with substantial egress time.
Let us now look at access time. How are goods supposed to get from where they’re made to the train station? With passengers, there are cars and connecting transit at the home end. There’s typically less centralization than at the destination end, but in a small origin city like the secondary French and Japanese cities, travel time is not excessive. In a larger city like Osaka it takes longer to get to the train station, but car ownership is lower because of better public transit, which increases intercity rail’s mode share. On freight, the situation is far worse: industry is quite dispersed and unlikely to be anywhere near the tracks, while the train station is typically in a congested location. Conventional rail can build a dedicated freight terminal in a farther out location (for example, auto trains in Paris do not use Gare de Lyon but Bercy); an enclosed system like Hyperloop can’t.
And if industry is difficult to centralize, think of farmed goods. Agriculture is the least centralized of all economic activities; this is on top of the fact that of all kinds of retail, supermarkets are the most local. Extensive truck operations would be needed, just as they are today. And yet, outside analysts are considering perishables as an example of a good where Hyperloop could compete.
With that in mind, any speed benefits coming from high-speed freight services vanish. There are diminishing returns to speed. Since the cost of extra speed does not diminish, there’s always a point where reducing travel time stops being useful, since the effect on door-to-door travel time is too small to justify the extra expense. The higher the total access plus egress time is, the sooner this point is reached, and in freight, the total access and plus egress time is just too long.
In passenger service, the problem of Hyperloop is that it tries to go just a little bit too far beyond conventional high-speed rail. The technical problems are resolvable, at extra cost, and in a few decades, vactrains (probably based on maglev propulsion rather than Elon Musk’s air bearings) may become viable for long-distance passenger rail.
In freight, the situation is very different. Successful freight rail companies, for example the Class I railroads in North America, China Railways, and Russian Railways, make money off of hauling freight over very long distances at low cost. Quite often this is because the freight in question is so heavy that even without substantial fuel taxes, trucks cannot compete on fuel or on labor costs; this is why Western Europe’s highest freight rail mode share is found in Sweden, with its heavy iron ore trains, and in Switzerland, Finland, Austria, with their long-distance freight across the Alps or toward Russia. Increasing speed is not what the industry wants or needs: past US experiments with fast freight did not succeed financially. The fastest, highest-cost mode of freight today, the airplane, has very low mode share, in contrast with the popularity of planes and high-speed trains in passenger service.
None of this requires deep analysis; in response to Hyperloop One’s interest in freight, an expert in logistics asked “why do we need to move cargo at 500 mph?“. The problem is one of face. The entrepreneurs in charge of Hyperloop One cannot admit that they made a mistake, to themselves, to their investors, or to the public. They are bringing the future to the unwashed masses, or so they think, and this requires them to ignore any problem until after it’s been solved, and certainly not to admit failure. Failure is for ordinary people, not for would-be masters of the universe. The announcement of the grand project is always more bombastic and always reaches more people than the news of its demise. It’s on those of us who support good transit and good rail service to make sure the next half-baked idea gets all the skepticism and criticism it deserves.
Pedestrian Observations 
I would say that cant is not really a problem. You could add a second support at each pylon towards the outside of the curve at the angle of the force vector caused by the dynamic loads – sort of the opposite of guying a utility pole. However that doesn’t solve the much larger logistics problems you identify. I’ve heard hyperloop proposed for moving freight from the ports of LA & LB to distribution in the Inland Empire, which just doesn’t make sense compared to rail or trucks. If you move a container 60 miles by truck it will take an hour; if you move it 60 miles by hyperloop at 500 mph it will take 8 minutes. For all your hyperloop expense, you save 52 minutes on moving a container that spent 2 weeks on container ship coming from China (http://www.cosco-usa.com/omd/schedules/CCC.htm) and will spend days or weeks in a distribution center before being sent out to a consumer.
Like passenger hyperloop, the only thing freight hyperloop will be competitive with is air travel. By its very nature air freight serves a small portion of freight traffic – freight that is very high value and very light weight. So yeah, if hyperloop can ship lobsters from Maine to Chicago or oysters from British Columbia to Los Angeles faster/cheaper than air, maybe it will compete. But even if it works it’s not going to be a significant portion of freight.
I agree with you but then playing a bit of devil’s advocate, what about the issue of space in the Inland Empire or Bakersfield being available for distribution versus places closer to the port. Then you also have the issue of particulate matter being especially high from the truck traffic along major freeways. I can see some sort of high speed freight being an instant connection between inland freight distribution centers and the ports opening up more land for redevelopment with limited exposure to pollutants for residents while also reducing truck and rail freight traffic in the urban region. Just want to think outside the (big-box) for a second while also realizing that reality is much different than fantastically hopeful ideas.
I’ve been thinking about this for a little bit now, we think of housing + transportation costs for people but what if we also used that formula for shipping affordability. Smart growth at ports is kind of an opposite to the Hyperloop idea. The idea would be to reduce the number of trips to distribution centers in the central valley by building up districts around the ports themselves, lowering VMT. There’s a professor at Berkeley named Leachman who has been looking at supply chains from China for big box stores which bring in a lot of the goods. It’s interesting some of his recommendations…
1. Ports, governments and railroads should wake up to the fact that push-pull (a.k.a. Consolidation – Deconsolidation) supply chains are more efficient, and we must plan to accommodate them.
2. Local control of land-use policies for supply-chain infrastructure has bad consequences. National interests need to be weighed against local ones.
3. Increased logistics land use near the ports can avoid the need for costly transportation infrastructure and can reduce environmental impacts.
Not sure I agree with #2 as there are more issues at stake with land use that wouldn’t be considered in a national frame.
But my take away from this is that we can have more “smart growth” for freight at the ports that accommodate that consolidation – deconsolidation model. Or we can figure out a way to ship faster to the inland ports without creating more VMT/Particulates. That would be the value of a hypothetical “hyperloop” solution that doesn’t seem reasonable from Alon’s analysis.
It’s also interesting to note how much of the container traffic is from Big Box Stores like Wal-Mart and Target
Leachman Presentation – http://bit.ly/2e258i2
You can find more of his work here:
http://ieor.berkeley.edu/people/faculty/leachman
This is not my area of expertise so there might be holes, but its interesting to think about it nonetheless.
There is a good case for freight rail to the Inland Empire. But it would be low-speed conventional rail, not Hyperloop.
I wonder if the easier thing to do would be to reduce truck & train pollution between the ports and the IE by electrifying RRs and going toward alternate fuel trucks (CNG, fuel cell, electric, whatever). The price per square foot that people pay for warehousing & logistics space in the IE is an order of magnitude less than what’s paid for housing & offices in the LA Basin & OC. Converting land near the ports to logistics would probably mean someone would have to accept much lower land values. Industrial space in LA is already under development pressure from residential development, though some warehousing facilities have been built/upgraded to serve very time sensitive goods. The industrial market in the LA Basin is extremely tight; vacancy is something like 1%. Nowhere to build though…
Do you know what percentage of pollution in the LA Basin comes from trains and trucks vs. cars? Cars don’t run on diesel over there, but they still dominate fuel consumption. Might be worth it trying to chase diesel transportation away from the basin if it’s a major contributor. (If not, lol at California banning cars the way Norway is and the Netherlands might.)
It looks like a fairly significant amount on freeways close to the ports. 12% of traffic on 110 Freeway is heavy duty trucks and 25% of 710 according to this 2014 research – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3910024/
The SCAQMD has a plan for attainment by 2025 (perhaps pending Trump dismantling the EPA), but it shows that even with zero emission technologies in cars and trucks, a large portion of the emissions will still come from “Federal sources” aka trains, planes, and ships. SCAG has put together a study on electrifying all the mainlines in the Basin, but the railroads have resisted because they claim that it would be too much of an operational burden for them to switch locomotives to enter the Basin even though they already add/remove locomotives to enter/exit the region due to the grades.
It’s not going to compete with air. Air spreads the cost of the very expensive airport and all the support an air system needs with passengers willing to pay extra to save time. . . well willing to pay less than the full cost of their automobile and save time.
Air has the aditional advantage to need no right of way. If you start flying fresh Maine lobsters to Iowa city and don’t make enough money, you try another destination. If this happens with Hyperloop, you’ve already sunk all the cost for a tube from Maine to Iowa. Not the best technology to try out new markets.
Would British Rail’s “Red Star” parcel service be considered high speed freight? From what I have read it was very successful but fell apart when the intercity rail network was balkanized after privatization. Instead of running special dedicated trains, every train including the HST “Intercity 125” had a luggage van space for such express freight, similar to airliners or even ocean liners and passenger trains of days gone by with their RPOs. No dedicated vehicle (train-set) or overall infrastructure (stations or mainline tracks), it utilized like today’s airlines assets (airliners, airports and air traffic) used primarily for other means, including the mass transport of passengers.
Red Star Parcels
Red Star TV Advert
In my mind for a TGV style freight service to be successful, it would have to be relatively long-distance like Spain to Germany, Rome to Paris, otherwise you would just send it by truck for a direct door-to-door deliverer. You would have to probably created dedicated freight terminals where transshipment would occur, and dedicate freight sets would be serviced and marshaled.
From what I know from American freight railroading, the key to a successful intermodal or perishable service is primarily running you trains on-time, and it’s not the top speed but the average speed that is important. And excellent example is Railex…
Wikipedia: Railex LLC
https://en.wikipedia.org/wiki/Railex
Railex Corporate Website
http://railex.com/
Sorry, I didn’t know the website would blow up the YouTube video that big! I also seem to have doubled posted, here is the Wikipedia page for Red Star, a few books I have on British Rail cover it.
Red Star Parcels
https://en.wikipedia.org/wiki/Red_Star_Parcels
My own take on Hyperloop (the concept not the company Hyperloop One) was that it was an attempt to create a home-grown, ie. USA, alternative to the established High-Speed Rail players, namely France’s TGV, Germany’s TransRapid maglev, Japan’s Shinkansen and Chūō-Shinkansen (ie. maglev) and China’s copies of all of the above. If this is the “cost” of getting HSR built in the US I would even applaud it.
In addition to being a blatant scam, its half-baked nature quickly was revealed:
and …
One of the most obvious reality-checks was a change from the “riding on a air cushion” concept to effectively maglev. And reduction in speed.
When one considers that the Chūō-Shinkansen is planned to run in a tunnel for more than 60% of the entire line, and 40 m underground (deep underground) for a total of 100 km in the Tokyo, Nagoya and Osaka city areas, the differences to Hyperloop is not so great. The main limitation on maglev trains is the squared-law of increasing air-resistance with speed. This is the reason why the only customer-carrying operating maglev, the Shanghai Transrapid operating 30km between the city and its airport, does not operate at its top speed except at peak hours. To save on electricity costs. I imagine the Japanese engineers would have looked at the practicality of reducing the air pressure inside those long tunnels. (The main issue is entry/exit just as it is for Hyperloop.)
Anyway even if it continues to evolve into a more conventional maglev, that is not necessarily a bad thing. of course the problem is that the $190 million or whatever, raised for Hyperloop One is not going into anything really technological but into management, PR and corporate lawyers pockets.
“As the ongoing attempt to build a Hyperloop tube in California is crashing due to entirely foreseen technical problems, the company trying to raise capital for the project, Hyperloop One, is looking at other possibilities in order to save face.”
that was never stated as Hyperloop One’s goal, that was Elon Musk’s goal, they are different entities and have different goals hence Elon not even being an investor, media doesn’t know how to parse that
The rest of the article may be correct but Hyperloop One has never really committed to passenger transportation…
can the font be changed to something that’s easier to read?
your posts are completely illegible because of the typography. i implore you to try these settings:
– font-weight: 400
– font-family: lato
– font-size: 18px
– line-height: 1.2em
Also reduce column width by 50%
The reason my column width is what it is is to make sure that when people comment, the column width doesn’t end up like on Tumblr 5 levels down.
I don’t have a problem with the concept in general. I can go to a bank drive-thru, and watch the pneumatic tubes throw my paycheck over my car and into the teller booth. The problem is, how do you effectively seal a vacuum in a tube that is 50 to 100 miles long? Particularly in areas with high diurnal temperature spreads. The “vomit comet” arguments are valid as well, but I think that problem can be overcome with seat dampers to mitigate the g-forces. And for freight, a Hyperloop friendly container system could be developed, as well as an Uberized last mile solution for shipping and delivery. IMHO, the biggest hurdle is the economics. Land acquisition costs for these lines (especially in places like California) would be insurmountable without partnering up with heavy rail, and using their corridors. Having been a past victim, er, employee, of major railroads, I don’t see the kind of open-mindedness to play with the new technology taking hold at 150+ year-old companies. And it is also true that freight doesn’t have the delivery pressures that require this kind of speed, and the perishable freight that might, doesn’t deliver the shipping value to pay for it. In short, the problem isn’t the technology itself, but the market that would use it.
You bring up a good point in the economics and it has been something I have been heavily researching the past weeks. It may be hard to get my whole point across, but hopefully you will understand. A group I work with has actually spoken to train companies as well as air travel and they are both interested in the Hyperloop. The train companies we have spoken to are interested due to the lack of high speed passenger rail options in the area we are researching. They would be willing to give access to their rail ways because they want to see faster travel options as well as bring back excitment to the rail industry in the United States (they see Hyperloop as another train system). Also, train companies invest heavily in real estate. If Hyperloop used the current rail stations that are not highly used, that land surrounding those stations would jump in value once Hyperloop was up and running. This would make for a highly profitable land grab by the train companies. The air industry is interested because they tend to lose money on short distance air travel (between 0-400 miles). These companies would partner with Hyperloop to sell tickets for shorter distance travel options, thus not wasting their own money for that travel. Also, the air industry is going to have a pilot crisis soon due to the high volume of forced retirees that will happen soon, so they do not wish to use their dwindling supply of pilots on low profit short distance travel. Overall, partnerships with these industries is plausible and is something we are looking into.
The problem is that airlines can’t really abandon short-haul feeder routes to a system that doesn’t feed the major airports. In Texas, one of the older HSR proposals, the T-Bone, reacted to this by saying the system would run directly to airports; based on low-resolution maps, the only DFW-area stop was DFW the airport, to the exclusion of service to Dallas and Fort Worth’s centers. In California, there’s no direct service to LAX, which I think is a fixable mistake, but there are plans for an HSR stop at Millbrae, close enough to SFO for government work.
Providing multiple stops in one metro area is a big advantage of conventional HSR. It can use legacy rail and legacy rights-of-way to access destinations, as on the SF Peninsula and even on the Harbor Subdivision in LA. It also travels at a lower top speed, compensating by not requiring any security theater, so the cost of multiple stops is reduced, while the benefit in reduced access and egress time is substantial.
Finally, re real estate, the proposed location for California HSR’s San Francisco station is Transbay Terminal. That’s not a lightly used location; that’s the middle of the central business district. At the LA end, Union Station is also pretty heavily used, right on the edge of the CBD. Tellingly, real estate development is not important to the portfolio of HSR providers: JR Central, whose revenues and profits are dominated by the Tokaido Shinkansen, has little to no involvement in real estate; in Japan it’s the commuter railroads that invest in real estate, mainly the private ones but also increasingly JR East, whose transportation revenue is about 68% Tokyo commuter rail and only 27% Shinkansen.
JR Kyushu is reportedly heavily invested into Real Estate, it was widely mention in the news of their recent IPO. The All Aboard Florida “Brightline” project also as a big Real Estate component. JR Central also redeveloped Nagoya Station including a big new tower complex called JR Central Towers. This was part of a strategy of diversification in business activities by the railway and was touched upon in Christopher Hood’s book “Shinkansen: From Bullet Train to Symbol of Modern Japan”.
JR Central Towers
https://en.wikipedia.org/wiki/JR_Central_Towers
When I look at the vast surface parking lots and empty land around the Albany-Rensselaer Station, the 9th busiest Amtrak station in the country, one half of Amtrak’s busiest city pair off the NEC (Albany-NYC), the station located directly across the river from the state capital, in the heart of “Tech Valley”… I know there is something wrong with the way most Americans think about intercity transportation and urban development!
Interestingly while several Japanese international airports have excellent rail connections, none, as far as I know are served by the Shinkansen. In the 1980s the failed “California Bullet” HSR project was to connect San Diego with both LA Union Station and LAX, utilizing a new elevated viaduct over a local Santa Fe freight branch line. That project might have succeeded with more state support (actual financial grants in return for ownership stake?) and they scaled some of it back, less Shinkansen and more a modern electrified double-track line shared by both freight and passenger trains, utilizing a Americanized version of Japan’s Class 381 tilting EMU train, with a top speed on standard gauge track of 125-mph. For the short distance (128 miles) that would have been good enough, and had reduced costs and need to acquire significant new ROW beyond the existing Santa Fe Surf Line.
Another big miss of a opportunity, there is a “out-of-service” in reality abandon double-track grade separated LIRR line that runs directly from the LIRR Mainline to the doorstep of JFK… its just sitting there… in Europe or Japan by now you would have by now seen that railway rebuilt and the airport served by a local “Heathrow Express” to Penn Station and now with East Side Acess to GCT or intercity “TGV” type service connecting with the NEC. In America trees grow up between the ties and the rails and many are advocating for this line the LIRR Rockaway Beach Branch to become a bike path/linear park. (Sigh)
Maybe the ROW a future Hyperloopy Line!? To LaGuardia!
My recollection of Hood is that he specifically contrasts the different levels of real estate investment by the JRs, and JR Central isn’t that invested (it’s instead investing in a maglev).
Rensselaer… yeah. I think it’s less about intercity transportation failure and more about local transportation failure. A European city would’ve developed it as a new central business district, the way Lyon developed Part-Dieu, and made sure to connect it to local transit well rather than turn it into a giant parking lot. Generally, European cities, whatever their other development failures are (see e.g. the giant exchange in the sewer socialism thread about Paris), tend to be pretty good about town centers; US cities overprovide parking even when there are sidewalks and such.
Re LA-SD, a lot of people hope for something like what you’re proposing to materialize once HSR opens. HSR trainsets are expensive, but it would still be worth it to electrify and double-track LA-SD and then run HSR trains through at lower speed. Since the proposed California HSR alignments from LA to SD goes via the Inland Empire, the time travel savings over an upgraded legacy route running fast trains are small.
Albany’s CSA is a little over a million people. Half of Lyon’s. With much lower gas prices.
Unless you want to ban cars it’s never going to have a robust mass transit system. Cars are too cheap, congestion – to some who has tried to get to the loading dock at a building in Manhattan – doesn’t exist, there is parking everywhere and cars are cheap. Did I mention cars are cheap? And there’s no congestion? Extend one or two of the higher frequency bus lines the few blocks across the river or run a fairly frequent shuttle. That’s as good as it is going to get. Because almost everyone has a cheap car.
That is easy to use because there’s little congestion and lots of parking.
There are a lot more good transit systems in metro areas in the 2 million area (Prague, Stockholm, and Vienna are really good, and Lyon and Hamburg are good) than in the 1 million area, but Geneva, Strasbourg, and Basel all have pretty good transit. Basel did in fact ban cars from the center.
The parking in Albany is cheap, but that’s a political decision made by the region. Can’t have state legislators taking transit, that’s only for the working class.
Fuel cost a lot more and their core wasn’t designed to keep the horse pollution away.
Albany’s loss came when the streetcar system was ripped out and not replaced. Like so many other cities.
What was lost in the Capital Region of NY:
http://alloveralbany.com/archive/2013/04/05/riding-the-trolley—-everywhere
Would have made quite a difference.
Lyon has a metro population of 2.3 million, and from the point of view of its TGV stations (and airport) probably services closer to 3m catchment. (It also services Geneva.) This is why it could support Europe’s first TGV (Lyon-Paris), as well as being halfway to the Med coast.
It doesn’t really make much sense in having HSR service airports as they are really substitutes/competitors to flying. And of course any major airport will have its rail link to its city’s downtown where HSR usually terminates. Building HSR track in metro areas is v. expensive and you don’t do it without very good reason. And as Alon has pointed out, the speed difference, time saving over such distances is not worth it.
The only exception I know of is in Paris CDG airport which now has a TGV station. Of course it doesn’t connect with Paris but is a way to bypass central Paris. But this wasn’t until about 25 years after introduction of that first TGV and almost 2 decades after the Eurostar. It arises because of the constraining geography–the land route to the south from a lot of northern Europe goes thru here; also special Eurostars service Marne-la-Vallée for Disneyland; and some summer direct services London to Avignon and probably eventually points further south (there is direct TGV to Barcelona now from Paris). Many people flying long-haul into CDG with other final destinations can use the TGV. Also it is part of a long-term strategy to take pressure off the TGV stations in central Paris. There are several other TGV stations planned in the Ile de France (IIRC, one is planned for La Defense? Hah, of course, especially for Alon so he doesn’t have to transit thru Chatelet-Les-Halles!).
Isn’t it possible to imagine some sort of springs or shock absorbers between the top of concrete pylons and the tube? A suspension system that would take care of canting through curves?
That takes care of the effects on the guideway, at extra cost, but the effects on the passengers remain. No matter what the cant is, there’s a gravity force vector pointing downward in the horizontal plane, and a centrifugal force vector pointing outward from the direction of travel; cant and tilt can rotate the vehicle so that its floor is perpendicular to the resulting force vector, but they can’t make the force vector different. At low lateral acceleration, typical of a conventional train, the difference in magnitude between gravity and the combined vector is small, so canting and tilting are highly effective at reducing passenger discomfort; if anything, a residual sideways vector is desired to avoid motion sickness. The outer limit of this is around 4.5 m/s^2 in the horizontal plane, which at Hyperloop speed requires a curve radius of 25.5 km. At higher lateral acceleration, which is required if the curve radius is reduced to reasonable levels, the magnitude of the combined vector is sufficiently different from that of gravity alone that passengers would feel a strong downward force every time the vehicle took a curve; at a curve radius of 10 km, lateral acceleration would be 11.5 m/s^2 in the horizontal plane, and even with perfect canting, downward force would be 15.1 m/s^2, or 5.3 excess m/s^2 over gravity (0.54 g). A plane takes off at 0.3-0.4 g. This is why I said it’s a barf ride.
There is a lot of mistaken engineering in the discussion throughout this thread about cant and support. A shock absorber still transmit force through its supports. All it does is reduce high frequency vibrations – it spreads the energy out through time.
The theory for all of this is simple geometry plus Newtonian physics. You are using the reaction supports and ground to accelerate the train or hyper loop cars in a new direction (i.e. left or right). The cost is friction and the strength necessary to support the reaction.
The discussion in the original post about strength in the support structure is also mistaken. The pylons, made out of reinforced concrete have plenty of tensile concrete (hence the reinforcement). I’m doing all of this without even preliminary calcs. But it is extremely unlikely the force imparted by the hyper loop itself, even with full-weight freight (e.g. trucking style freight not iron ore), would overwhelm the support’s capacity. Anyway the solution is not complicated, you make the supports angled with respect to the vertical plane. The supports would look like a un upside-down W or U-V combination. The real problem is uplift or overturning of the foundations. The limitation will be on the width of the W supports in transverse or the curve radius of the track (or as lastly the weight of the train).
The comment about seat dampers to mitigate passenger forces, again, you can only remove the high-frequency accelerations. You are accelerating the passengers sideways, that is the point, to force them to the left at a high rate of speed. You can not ‘damp’ or ‘absorb’ this force.
JonS (2016/12/31 – 11:56) wrote:
Is it not the point that more or most of the force of a turn, via cant, is put into the vertical dimension (ie. w.r.t. the cabin) and thus the passenger is simply pushed into their seat, rather than thrown sideways. Exactly what happens with roller-coaster rides being able to make sharp turns. Implemented properly on a mag-lev system it could be perfectly smooth and barely noticeable; even glasses of water would be perfectly stable on tables etc. Of course since the track has to be fixed (hmm if you have it in a tube?) then there will only be specified speeds at which it works well. Naturally there will still be limits with respect to speeds and curvature and degree of cant.
When I heard of Hyperloop, I did start trying to think of applications for faster-than-air-freight. All I could think of was moving extremely time-sensitive medical supplies like organs for transplant, and I suppose unless you’re going across tremendous distances, you could just use a helicopter for that.
Given Musk’s actual behavior in practice — he’s a master of using existing technology and cutting costs — if he seriously started working on Hyperloop, he’d end up replacing the expensive gimmicky tubes with ordinary self-stabilizing conical wheels on rail tracks, and figuring out a way to make cheaper high speed rail.
I wish he would.
(Example: he talked about fully reusable rockets, then backed off and only made the first stage reusable. Example: he talked about a new-age electrostatic powder system for painting cars, then backed off and built a completely standard paint shop. Example: he talked about “Autopilot”, then built a fairly low-key driver assist system.)