Elon Musk's Hyperloop- The Faster Than Sound Transportation System

[LorenS]

Re: Elon Musk's Hyperloop- The Faster Than Sound Transportation System

Many people had been envisioning Hyperloop as something akin to a giant vacuum tube with electromagnetically-suspended capsules running inside of it – these capsules would be loaded with passengers and simply be sucked along.

According to Musk’s announcement, however, one of the problems with such a setup would be the fact that the air column within the tube would build up in front of each capsule as it traveled down the tube. He likens it to the resistance you encounter when trying to push a plunger through a syringe full of fluid. His solution? Put an electric compressor fan on the nose of each capsule, that would draw the air through it.

So are the tubes evacuated or not? If the tubes have "no air", then the air resistance is not an issue.
If there is air in the tubes, then the amount of power required just to compress the air will be more than any small battery pack can provide.

In my opinion, the only benefit to the "tube" would be the ability to evacuate it and eliminate air/wind resistance. Otherwise you may as well just use rails and let the propulsion system deal with the air drag.

[think365]

Re: Elon Musk's Hyperloop- The Faster Than Sound Transportation System

If we had the sort of tax system that would recover the growth in asset values though taxes while also adding real user fees to roads, it would certainly make some of these projects look more economical more or less the real economic reality instead of computing without the account of the road subsidies and real estate free rides.

We already do have that sort of tax system. They're called "ad valorem" (Latin for "according to value") taxes and are currently levied on real estate, business personal property, estate & gift property, and consumption of tangible assets (sales tax, use tax, etc.) in the United States. Sometimes they are also referred to as "wealth taxes". In some countries they severely tax your net worth over a certain threshold amount in addition to all the other taxes just mentioned (usually resulting in a mass exodus of the "productive class" out of the courntry, which is what is happening now in France). One of the reasons governments can't tolerate deflationary spirals (and will literally "print for their lives" to inflate nominal asset prices) is because when asset values stop growing and actually decrease in value, it puts a huge hole in their tax receipts (and becomes an even bigger problem for the asset holder who often goes bankrupt and loses everything). Owning real estate along with all the associated taxes, liabilities and risks is hardly a "free ride".

[EJ]

Re: Elon Musk's Hyperloop- The Faster Than Sound Transportation System

I just skimmed through Mr. Musk's paper.
Like any good promotional concept study, it glosses over the serious practical engineering issues to "...sell the sizzle..." of what might be technically possible.
Two items that jump out to me are:

1. Emergency egress.
Musk proposes a little tube just 4 1/2 feet in diameter filled with a passenger capsule, with passengers reclining nearly to the point of laying flat. Zero room for any door or hatch to open, or for people to pass between the vehicle and the wall. I doubt a real person could even move from the front seat to the back with the capsule closed. The seating arrangement is a lot like a bobsled, not like a city bus. If that train stops, well, you are stuck until something pulls the capsule to the nearest station so you can get out. If there is a fire, well, you've been unlucky and had a very bad day. Sorry.

This egress problem exists for more conventional elevated monorails. Years ago our research team had this conversation with some German engineers proposing an elevated monorail in Florida. The Germans kept answering that a breakdown between stations simply was not possible, and neither 80 year old aunt Mildred nor little 3 year old Bobby need worry about scrambling out of the train to a narrow catwalk 50 feet above the sidewalk, and perhaps plunging to their demise.
Outside an elevated monorail there is at least fresh air to breath. The Hyperloop has no air in the tube. Maybe toxic smoke from a burning battery pack, but no air.

2. The last mile problem.
To take the Hyperloop, one must get down to the San Francisco station; park ones car; check luggage; and wait to board and depart.
Arriving in Los Angeles, one must get off the capsule; get ones luggage; go rent a car or board a bus or taxi; and get to ones final destination a few miles from the station.
I would be surprised if that did not require at least one hour at each end. The hyperloop ride takes 35 minutes. So instead of a 6 hour drive door-to-door, we would get a 2 1/2 hour trip with two station visits.

I am willing to speculate that this system concept for San Francisco -to-LA is the technical sweet spot for the whole idea, and trips that are much longer or much shorter results in a system design and costs that become even more absurd. Large unaffordable tubes; impossible energy requirements for air handling and propulsion; astronomical vehicle costs; requirements to move away from on-board batteries to a hard-wired system with thousand of miles of copper...
That is pure speculation by me, but I would love to see the similar study for a 50 passenger capsule with a lavatory and coffee service going from New York to LA.

If you get claustrophobic riding the Tube in London you can forget about riding in a Hyperloop pod.

Even a quick read of the plan quickly produced four false cost assumptions.

False Assumptions #1 and #2: Instances of the need to buy rights of way for a loop between San Francisco and LA will be low and the few that do occur will be on farmland and farmers are used to having power lines on their property so buying rights for Hyperloop will be no big deal.

The assumption isn't even logical. The national highway system was not designed to connect only major cities but cities in between. A casual look at the I-5 reveals dozens of instances of curves too sharp for 700MPH speed through urban or suburban areas. The path will have to be straightened and deviate from the I-5 through land rights purchases. Using lower project cost estimates of electricity transmission lines I estimate that approximately 3,000 acres of land under the loop will have to be purchased at a capital cost of $800 million to $1 billion.

False Assumption #3: The required 25,000 pylons can be built for an average of $100K apiece.

To build cheap steel pylons for power lines the cost multipliers depending on terrain are as follows.

The cheapest reinforced concrete pylon will cost $100K if it is less than 30 ft high high and is built on flat scrub land. A 60 ft pylon built on forested land will cost $300K. On average pylons will cost $200K each, doubling the cost estimated by Musk to $5 billion.

False Assumption #4: Only a few tunnels need to be built.

Hard to believe that only a few tunnels will be needed to get over 141 miles of Tehachapi Mountains between the San Joaquin Valley and LA. The Southern Pacific Railroad had to dig 18 tunnels to build the long, snaking track over the mountains in the 1870s. The mountain is the primary technical challenge for the $68 billion California bullet train project. For tunnels straight enough for the Hyperloop I estimate 10 miles of them will be needed at a conservative cost estimate of $300 million per mile. There's another $3 billion.

So far using readily available cost estimate methods we've found $9 billion in costs that Musk's plan missed. Even with the expensive tunnels and land rights purchases the pods will have to slow repeatedly along the way, bringing the ride time up to over 1 hour versus 35 minutes.

I expect that further digging into the plan will find several times as much in underestimated engineering, third party, construction, and other costs. Back-of-the-envelope the total cost is more likely to be $20 billion to $25 billion, still cheaper than the bullet train, but far less practical; the audience of travelers who will submit to sitting prone in a chair inside a tube for an hour unable to get up and go to the bathroom is too small to recoup the cost.

[thriftyandboringinohio]

Re: Elon Musk's Hyperloop- The Faster Than Sound Transportation System

So are the tubes evacuated or not? If the tubes have "no air", then the air resistance is not an issue.
If there is air in the tubes, then the amount of power required just to compress the air will be more than any small battery pack can provide.

In my opinion, the only benefit to the "tube" would be the ability to evacuate it and eliminate air/wind resistance. Otherwise you may as well just use rails and let the propulsion system deal with the air drag.

You have it right, LorenS.
The tubes are evacuated down to 1/1000 of normal atmospheric pressure for the reasons you mention.

That still leaves a little bit of air in the tube, which still wants to pile up in front of the capsule.
For those who are conversant in fluid dynamics, the remaining air forms a shock wave that chokes the flow around the capsule (mentioned as the Kantrowitz limit, though I think of it as Fanno/Rayleigh flow)
The capsule's on-board compressor (powered by the on-board battery) pumps that air from the front of the moving vehicle and discharges it out behind the vehicle, removing the choked-flow condition, allowing higher speeds.

So you are correct, LorenS, the reason for a closed tube is to hold a partial vacuum.
Given that they have that sturdy tube, they also use it as the structural weight-bearing road bed; as the guide rail for steering forces; and as the stationary part of the low friction air bearing.

[thriftyandboringinohio]

Re: Elon Musk's Hyperloop- The Faster Than Sound Transportation System

If you get claustrophobic riding the Tube in London you can forget about riding in a Hyperloop pod.

Even a quick read of the plan quickly produced four false cost assumptions.

False Assumptions #1 and #2: Instances of the need to buy rights of way for a loop between San Francisco and LA will be low and the few that do occur will be on farmland and farmers are used to having power lines on their property so buying rights for Hyperloop will be no big deal.

The assumption isn't even logical. The national highway system was not designed to connect only major cities but cities in between. A casual look at the I-5 reveals dozens of instances of curves too sharp for 700MPH speed through urban or suburban areas. The path will have to be straightened and deviate from the I-5 through land rights purchases. Using lower project cost estimates of electricity transmission lines I estimate that approximately 3,000 acres of land under the loop will have to be purchased at a capital cost of $800 million to $1 billion.

False Assumption #3: The required 25,000 pylons can be built for an average of $100K apiece.

To build cheap steel pylons for power lines the cost multipliers depending on terrain are as follows.

The cheapest reinforced concrete pylon will cost $100K if it is less than 30 ft high high and is built on flat scrub land. A 60 ft pylon built on forested land will cost $300K. On average pylons will cost $200K each, doubling the cost estimated by Musk to $5 billion.

False Assumption #4: Only a few tunnels need to be built.

Hard to believe that only a few tunnels will be needed to get over 141 miles of Tehachapi Mountains between the San Joaquin Valley and LA. The Southern Pacific Railroad had to dig 18 tunnels to build the long, snaking track over the mountains in the 1870s. The mountain is the primary technical challenge for the $68 billion California bullet train project. For tunnels straight enough for the Hyperloop I estimate 10 miles of them will be needed at a conservative cost estimate of $300 million per mile. There's another $3 billion.

So far using readily available cost estimate methods we've found $9 billion in costs that Musk's plan missed. Even with the expensive tunnels and land rights purchases the pods will have to slow repeatedly along the way, bringing the ride time up to over 1 hour versus 35 minutes.

I expect that further digging into the plan will find several times as much in underestimated engineering, third party, construction, and other costs. Back-of-the-envelope the total cost is more likely to be $20 billion to $25 billion, still cheaper than the bullet train, but far less practical; the audience of travelers who will submit to sitting prone in a chair inside a tube for an hour unable to get up and go to the bathroom is too small to recoup the cost.

Mr. Musk has also completely ignored all the ancillary systems required to actually operate the thing.
Items like:

- giant air-tight gate valves every so often to isolate tube sections for maintenance and repair
- roadway along the track for maintenance and repair crews
- specialized capsule moving and lifting cranes
- hatchways or ports into the tube to repair and inspect
- enormous depot servicing shops and garage areas
- sidings and switches
- The trackside (tubeside?) sensors, controls and signals, and the dispatching control center (these controls alone may be twice his cost estimate for the whole system)
.
.
.
P.S. It occurs to me that a smart guy like Musk might visit iTulip or even be a subscriber.
If so, no offense intended, Elon.
Your enthusiasm for new things and breakthroughs is inspiring, and it's fun to think about your concept.

[dcarrigg]

Re: Elon Musk's Hyperloop- The Faster Than Sound Transportation System

Mr. Musk has also completely ignored all the ancillary systems required to actually operate the thing.
Items like:

- giant air-tight gate valves every so often to isolate tube sections for maintenance and repair
- roadway along the track for maintenance and repair crews
- specialized capsule moving and lifting cranes
- hatchways or ports into the tube to repair and inspect
- enormous depot servicing shops and garage areas
- sidings and switches
- The trackside (tubeside?) sensors, controls and signals, and the dispatching control center (these controls alone may be twice his cost estimate for the whole system)
.
.
.

Frankly, if the California High Speed Rail Authority is saying $13 billion for tunnels, I don't know how Musk expects to have fewer tunnels. Tunnels are the single largest cost in the project, followed by Viaducts:



It's not the train or the train track or the electrification that's so expensive. It's everything else:



I'm not sure how a tube would need many fewer or much cheaper viaducts, tunnels, land, or other support structures than a train.

I imagine that when it is all said and done, the cost may be quite comparable to the train, only the train is a relatively proven and mature technology. I imagine the potential for cost overruns for some technology that is completely new would be significantly higher.

Amtrak proportions look similar in the new dedicated high speed line plans for the Bos-Wash corridor at $151 billion. Since the population's denser, the project becomes much more complicated on the east coast. Why would a tube be cheaper?

[thriftyandboringinohio]

Re: Elon Musk's Hyperloop- The Faster Than Sound Transportation System

....I imagine that when it is all said and done, the cost may be quite comparable to the train, only the train is a relatively proven and mature technology. I imagine the potential for cost overruns for some technology that is completely new would be significantly higher.

Bingo.
Sometimes associates complain about the high price of an item or system and suggest we design and build our own for less. I tell them it's always cheaper to buy something that exits than to try to figure it all out from scratch.

That's especially true for big civil system like aircraft, roadways, trains, power grids, cargo ships...
Those things exist within a whole established ecosystem of tools, standards, regulation, support services, mating equipment....really a little economy of goods and services and thousands of people who know what to they are doing.
Those ecosystems don't spring up overnight, and the Hyperloop would wish for them every hour of every day.

[photon555]

Re: Elon Musk's Hyperloop- The Faster Than Sound Transportation System

Perhaps it would be viable in shorter lengths where there are no terrain difficulties. The average speed would be less, but the passengers would not be confined for so long either. In fact, in could be marketed not only as a transportation service but as the world's longest, fastest "amusement park" ride. People are willing to pay the better part of a hundred dollars in order to stand in line for hours waiting for a 30 second ride, so why not a similar amount for a 10 minute ride with little waiting. Add a few lights and gizmos and give the passengers a game controller so they can participate. At the end of the line give a printout with the passenger's score and post the 10 highest scores. It might be feasible to keep the "ride" going 24/7 for the younger generation. Books of rides limited to off hours could be marketed as gifts, and there could be prizes for the highest score every month and year.
I don't see it succeeding just as transportation. There has to be a thrill factor, like riding the Concorde to justify a large premium that would make it profitable.

[thriftyandboringinohio]

Re: Elon Musk's Hyperloop- The Faster Than Sound Transportation System

Perhaps it would be viable in shorter lengths where there are no terrain difficulties. The average speed would be less, but the passengers would not be confined for so long either. In fact, in could be marketed not only as a transportation service but as the world's longest, fastest "amusement park" ride. People are willing to pay the better part of a hundred dollars in order to stand in line for hours waiting for a 30 second ride, so why not a similar amount for a 10 minute ride with little waiting. Add a few lights and gizmos and give the passengers a game controller so they can participate. At the end of the line give a printout with the passenger's score and post the 10 highest scores. It might be feasible to keep the "ride" going 24/7 for the younger generation. Books of rides limited to off hours could be marketed as gifts, and there could be prizes for the highest score every month and year.
I don't see it succeeding just as transportation. There has to be a thrill factor, like riding the Concorde to justify a large premium that would make it profitable.

That's good thinking, photon555. Our group once spent a few days with engineers (Imagineers!) at Disney World in Orlando.
They told us the park has a history of installing ride attractions that morph into unintended transportation systems widely used by guests.
The monorail. The steam trains. The riverboat ride. The big paddle wheel boats across the lake.

You might have found a way to jump-start the hyperloop as a smaller attraction that could scale into a bigger, more robust transportation system.

[photon555]

Re: Elon Musk's Hyperloop- The Faster Than Sound Transportation System

That's good thinking, photon555. Our group once spent a few days with engineers (Imagineers!) at Disney World in Orlando.
They told us the park has a history of installing ride attractions that morph into unintended transportation systems widely used by guests.
The monorail. The steam trains. The riverboat ride. The big paddle wheel boats across the lake.

You might have found a way to jump-start the hyperloop as a smaller attraction that could scale into a bigger, more robust transportation system.

Thank you. That's an interesting bit of recent history about the rides morphing into transportation infrastructure. Another plus for starting small with the idea of installing units in multiple locations is that the R & D can be amortized. The first install can be publicized as a demonstration project which would take the pressure off meeting a strict timetable and having everything work perfectly as designed at first. In fact, it might be advantageous to use the NASA approach of scaling up and meeting discrete way points along the path to the goal.

[rlskaggs2003]

Re: Elon Musk's Hyperloop- The Faster Than Sound Transportation System

Your mention of the Tehachapi Mountains compel me to comment. I develop wind farms in the Mojave Desert and am very familiar with the region. I really do laugh at the thought of attempting to permit and construct something such as Hyperloop at an economic cost over a time period under 1,000 years through this neck of the woods. I am not sure what routing Musk would anticipate, but with the patchwork of federally owned lands in this region (administered by BLM) connected section by section not unlike a checkerboard, good luck with avoiding NEPA review. When it takes, in some instances, years to permit the right to install something as benign as a temporary meteorological tower on BLM property, I'd love to see how long the NEPA process would take for a project of this magnitude should it have the unfortunate necessity to cross even 1" of BLM land. Let's not forget CEQA, either. Oh, and all the other local and county governments and state agencies (including CDFW, regional water quality control boards, etc.) that would have a say in the permitting of the development. Incidental Take Permits, streambed crossings, etc. etc. Man, that would be fun. Of course, even if you thought you'd be successful with the permitting there is the private land issue as EJ mentions. You'd have a gazillion transmission lines and gas pipelines to cross. Underground aqueducts, too. The kind that supply water to millions of southern Californians. If all of this doesn't scare you, imagine trying to gain control of private lands in the way of the project that may have existing infrastructure on top. Like a wind farm, for example, that's leased the underlying land and encumbered it with financing provided by 100's of participating lenders.....Good fun.

[gwynedd1]

Re: Elon Musk's Hyperloop- The Faster Than Sound Transportation System

We already do have that sort of tax system. They're called "ad valorem" (Latin for "according to value") taxes and are currently levied on real estate, business personal property, estate & gift property, and consumption of tangible assets (sales tax, use tax, etc.) in the United States. Sometimes they are also referred to as "wealth taxes". In some countries they severely tax your net worth over a certain threshold amount in addition to all the other taxes just mentioned (usually resulting in a mass exodus of the "productive class" out of the courntry, which is what is happening now in France). One of the reasons governments can't tolerate deflationary spirals (and will literally "print for their lives" to inflate nominal asset prices) is because when asset values stop growing and actually decrease in value, it puts a huge hole in their tax receipts (and becomes an even bigger problem for the asset holder who often goes bankrupt and loses everything). Owning real estate along with all the associated taxes, liabilities and risks is hardly a "free ride".

I am incredulous . I have never so much as heard of a "tax on property". Do other people know or are you just so precocious from the very day you were born?

[Verrocchio]

Re: Elon Musk's Hyperloop- The Faster Than Sound Transportation System

Hmm... Passengers recline in a capsule that travels at a high rate of speed in a tube that has no egress between LA and SF. The tube runs more or less on top of the San Andreas fault.

Elon, you can't be serious.

[wayiwalk]

Re: Elon Musk's Hyperloop- The Faster Than Sound Transportation System

Hmm... Passengers recline in a capsule that travels at a high rate of speed in a tube that has no egress between LA and SF. The tube runs more or less on top of the San Andreas fault.

Elon, you can't be serious.

+1

But based on a list of his ideas (I think the last one was to start a colony for 80,000 people on Mars) I read through today on some website, maybe his alternate career is along the lines of magazine publisher?

Popular Science archive">

[wayiwalk]

Re: Elon Musk's Hyperloop- The Faster Than Sound Transportation System

Wait, this one is better, it has the "fan"....


Popular Science - April 1935
via | buy on eBay | read | add



Popular Science - April 1938
via | buy on eBay | read | add

I love big ideas too, but agree there are just too many flaws in what he is throwing out there.