Hyperloop is a pipe dream


See what I did there…“pipe dream”…lol…Ahem. Sorry.

Here’s a little snippet for those that haven’t seen the promise of 30 min cheap transportation between LA and SF:

Anyway. Hyperloop will never ever be safe or cost-effective. I cannot for the life of me figure out why media organizations on ALL sides are being duped into believing this fantasy. It really demonstrates the severe lack of simple science knowledge in the media and the public in general.

To create a hollow tube made of steel several hundred miles long (a single peice of steel welded together) that runs above ground and pump almost all the air out of it is beyond ridiculous.

There are a few technical problems and a few practical problems that will prevent it from ever happening.

Problem #1

First, unlike pipelines that carry liquids the tube will be empty and exposed to the sun. The sun will heat the steel on the side it faces. This will create expansion on the hot side that will cause it to swell, Since the heating will only occur on the hot side, it will want to bend and curve (as opposed to stretch uniformly). In a tube with liquids, the liquid helps to cool the walls of the pipe and absorbs the heat and makes heating of the pipe by the sun more uniform. Pipelines are smaller tubes and larger tubes don’t have anywhere near the pressure of a near vacuum.

Train tracks are a good example of what happens when steel gets hot (Remember that SoCal can be crazy hot at times).

Take this article from Business Insider

An 1800-foot length of rail will expand almost one foot with an 80-degree change in temperature, for example.

The tube will be hundreds of miles long and even if it expanded 1 foot for every mile between LA and SF (one-quarter of what a railroad track would expand) that’s still just shy of 400ft of expansion. If it expands at the same rate as a railroad track, we’re talking 1000’ of expansion.

A railroad track is comparatively strong and is more uniformly heated than a tube with an 8-10’ diameter. The problem for the tube is it will have large temperature gradients between the hot and cool sides. If the prototypes I’ve seen are any indication of how it’s made, the bottom of the tube will be filled with concrete, creating a flat surface for the vehicle to ride on inside the tube. The concrete will act as a sink for heat making the gradient problem even worse.

Problem #2

The tube will be close to a total vacuum. There’s talk of building them between LA and SF and DC and NYC.

Now, the LA to SF idea will effectively create the largest vacuum chamber in the world. The idea is to put several hundred, perhaps even thousands of people in these vacuum chambers and send them at close to the speed of sound through them.

A single failure in the tube would result in everyone in the tube being killed as a wall of air rushes into the tube and the cars inside slam into it. It would become an undefendable target for terrorists. Assuming “1/2 thick steel walls a .50 caliber Green (if I remember this round is M903 SLAP), a black or red tip could easily penetrate. The Green tip can penetrate over 1”@500yrds depending on the hardness of the steel. Homemade tannerite or fertilizer explosions could also breach the tubes if set up correctly.

When you cut a train track or blow up a plane, you don’t kill everyone on the same track or everyone in the air. Everyone in the tube would likely be killed or severely injured. And if they did survive, the tube would have to have escape ports, but the ports could only be opened if the tube were pressurized. Creating pressure doors through the length of the tube would be cost prohibitive, create points for vacuum leaks and stress points.

Musk is either an idiot or if you read the fine print on the competitions he holds, a genius. When teams build “pods” for test tracks. Musk get’s to keep all of the technologies that engineering teams around the world bring and compete with. So if someone does come up with something groundbreaking, he get’s to keep the idea and owes no one anything.

Any thoughts?


Interesting info…allow me to add this:

There seems to be only one public transportation system that breaks even or even makes slight profit is the Hong Kong transit system, the rest the world over are losers, especially so in the US. Most of the US ones need both local, state and federal taxpayers money to stay afloat at all. And never pay back even the cost of the build out or ongoing maintenance.

All public transportation does is foster more people to rely upon the govt to take care of them at taxpayers expense…hyperloop is just an Obama idea to help his liberal buddies get rich off.


I believe there may be other, harder to quantify benefits of public transport, but not anything I want to argue about.

I knew it wouldn’t be long before this was framed as a “Liberal” idea…lol

Though you are right, liberals on the far left eat this s*** up. They can’t help themselves. Anything that sounds green.


“Sounding green” and BEING green are two entirely different things.


We don’t agree very often, so let me enjoy this moment.


I think Musk is mostly a con man with dumb ideas and a sales pitch but a few thoughts from a layman on this idea.

  1. I thought a vacuum would remove heat and make the tube uniform in temperature?

  2. I thought very little vacuum would be required to get a free moving object going (Nullifying concerns over a breach beyond just stopping the transport)?

  3. As to the concerns over tube shape changes, I thought the concrete track would alleviate any concerns of stability so as long as the tube was of adequate size it could alter in shape with impunity?

  4. Escape hatches could be made relatively cheap like airplane doors without leaking being much of an issue?

  5. Popping a hole in the tube with a high caliber munition would certainly create a leak but if the round did not strike the transport directly what would be the significant risk?

  6. I am pretty sure there are external coatings that can provide a seal in the event of a breach (like a gunshot)?

  7. A tube could be constructed with slip joints every so often (using lubed O-rings) and still seal adequately to maintain vacuum, wouldn’t this alleviate concerns over growth and contraction due to ambient temperature?

  8. Automatic brakes deployed in the event of vacuum dropping to zero would seem like an adequate safety measure in the event of a Terrorist type attack on the tube, unless the timing was so perfect as to destroy the tube at the precise moment the transport was passing I don’t see the concern for total loss of life?

I am not at all qualified to build or design such a beast but these problems seem manageable from a layman’s perspective.


Hey! Ret, thanks for joining in. I’m no engineer, but I have researched this quite a bit and, quite frankly, was initially hopeful that something like this was possible, though the skeptic in me started to question of few things and my opening post was a little bit of what I uncovered.

So let me address your points as best I can…

Vacuums definitely wouldn’t transfer heat through the tube, but wouldn’t do anything to prevent uneven heating on the outside.

Here is a pic of the scaled-down prototype. It was about 1000m (1km)’ long and about 1/2 the diameter of the planned full-scale version.

Now here are a couple of thermal imaging pics taken on an average 75 degrees F day:

Here is a shot of the bottom where the temp near the bottom was about 66F

And here is a shot of the same area close to the top where the temps near the top reach about 86F (the pic shows 28C)

Now, obviously, the gradient between the top and the bottom is about 14F. now given the expansion properties of steel, given the thermal gradient, in this case, the top of the tube over 1km would stretch about 4" longer than the bottom. Probably not even noticeable. However, 381miles long and the difference will be about 300’ (though again, that’s just a 14F difference between the top and bottom).

Not sure I understand this…?

If the passenger module is traveling at 700mph (150mph faster than a 737), a shift of just a few inches would likely be felt as several G’s of force. I mean, it’s not like a passenger plane where the wings act like springs and absorb most of the shock when buffeted by pockets of dense air. The car will be moving through a steel tube.

Perhaps, this I’m really not sure of…But, I would argue that a 381-mile long tube, if it had escape doors, what, every 100 yards would mean 6705 doors and 6705 chances for leaks? I mean a plane might have 2-3 doors over it’s 100’ length?

The other problem is that passengers would be a vacuum tube. Unless the entire tube was pressurized (or it could be sealed up in separate sections) and smaller sections pressurized, you wouldn’t be able to open the doors anyway.

It’s not that this problem cannot be overcome, it’s just that the simplicity of the idea is getting increasingly more complex and expensive.

Presumably, the passenger “cars” would be light, so they could float on the mag-lev rail. With almost no air in the tube, the car wouldn’t have to be built like a plane as the car would’t experience air friction. If it flew at 700 miles an hour into a pocket of air, it would be like driving a car into a pool at high speed. Compared to the vacuum, air would be incredibly dense.

Obviously a 1/2" hole created by something the size of a .50 caliber round wouldn’t lead to a catastrophic failure. I think we can say that sensors in the tube would detect changes in pressure and the cars in the tube would stop (though at 700mph one would think that a safe stop would take several miles). So, you may be right, as long as there wasn’t a car near the breach of a newly created bullet hole, the cars could be brought to a stop.

However, a catastrophic failure, say from an explosive could potentially kill everyone in the tube, or at the very least injure everyone. Remember it’s a vacuum. If the tube were breached air would rush in at extremely high speed to fill the void all the way down the length of the tube, in both directions from the breach. Given the cars would fill the tube, they would likely be pushed into each other by incoming air.

The cars wouldn’t even have to be moving. The air rushing in would, and I just guess now because I really don’t know, but I’d guess that air would travel down the vacuum tube at incredible speed. Sort of like water rushing into a submarine deep underwater.

Perhaps, we’ve solved more difficult technical challenges as humans…However, I think you underestimate the incredible pressure that would exist in a tube of that size with no air in it…

This is what happens when the atmosphere pushes down on a railroad car.

Again, neither of us are engineers, but given the research I’ve done, I can’t imagine it would be possible given a tube of this size, temperature gradients involved and the precision fit necessary to maintain a vacuum.

It would be one thing if we were talking about a tube 1000m long tube. That would be hard. But LA to SF is 613,000m!

Again, air rushing in would likely push all the cars in the tube towards each end causing collisions. If the cars become stuck (or held in place with braking systems, and there were air on one side and a vacuum on the other, air squeezed past the cars would likely be rushing so fast it would tear the cars apart.

Any engineers here?

What do you think, am I wrong?


I misunderstood the vision, my former comment was based on the assumption that Musk wanted to propel the transport via vacuum from point to point; I see now that he wants an electromagnetic propulsion and the vacuum and pressure concerns were rooted in the massive air displacement that the transport would create at speed.

So yes I share your concerns, but I wonder if my incorrect assumption about how the transport was propelled would be a more plausible design?

Creating a small vacuum to suck the transport from point to point would eradicate the pressure concerns, the transport would still have to be pressurized in the cabin but no part of the structure would be exposed to extreme amounts of vacuum or pressure?


Ohhhhhh… Now I understand. Like the old bank vacuum system in the drive through. Have to give it some thought, but at first glance, you might be on to something!


Actually, I don’t think the transport would have to be pressurized in a vacuum propelled system; there would also be no need for the transport to be constructed to withstand extreme pressure so it could be much lighter.

Leaks would not render the system unsafe or inoperable, they would just require more effort to maintain the vacuum and if they became too large the only consequence would be a slower moving transport until the leak/leaks were repaired.

The transport could be attached via a monorail from above which could not detach due to the altering shape of the tube as temperatures varied.

There is already O-ring tech that is designed to handle far greater temperature variations and pressures than this system would be subject to.


RET: Your opening line says it all.

His suck tube sucks. I won’t even bother to address the engineering challenges. From a practical standpoint there is little practically involved. The cost to build and maintain would simply solely depend upon Federal level taxpayer support and IMO that makes it a nonstarter over existing tech.

The cost to buy a ticket to ride will not make a dent in the cost to support, so again we have ME buying the rich a ticket for them to ride…kinda like every time I see an electric car go down the street I know I own a part of that as my tax money gave him the subsidy it took for him to buy it…

Anyone take note of the GM announcement that by 2023 they believe 100% of all the cars they make will be all electric. Electric cars simply fail the economic test of can I afford this without the taxpayer helping me? NO! Now you understand why the auto makers are jumping on the electric stupid train, because the taxpayer will be subsidizing them. Wait till you hear the sucking sound of the Suck Tube…

Proposed Missouri hyperloop would forge 25-minute connection across the state


Much like most here the man is a con artist/genius. He knows his ideas area no-gos but the tech that he can get from R&D are a millions times more valuable than if it actualy panned out.


That’s five years from now. With gas prices this low, it makes no sense. Electric cars are like 3% of the market. And that’s with the tax credit… which if 100% of GM sales were electric, almost no one would qualify for(it’s capped at 200k credits per manufacturer).

Edit: My bad. It’s not 3% EV, it’s 3% EV+Hybrid with Hybrids making up 2/3 of the 3%. EVs are less than 1%.


So California alone has more sales than the entire rest of the US combined. Left-wing green culture, or does California further subsidize EVs?


Now I don’t follow this issue that closely, but I suspect that the rest of the world is going to drag the US into the electric age as India has announced that petrol cars will be illegal by around 2030 with Germany, Netherlands, Scotland, and Norway to follow suit. I’ve seen reports that China will be close behind, banning petrol cars by 2040. California, the nations largest state, may also do the same and I suspect other states will follow California’s example.

I predict this will put a sizable strain on the nations electrical grid as a large and reasonably fast shift to electrics will begin to increase the demand for electricity.

Much of the rest of the world is taking electric seriously. We have the capacity to lead the world, but instead, our President is focused on pandering to the perception that coal has a future as an energy source long term and taking away incentives to renewables.

The fact that the US has so much coal is all that more a reason for those that oppose the US to do whatever they can to move out of coal.

The future is in renewables.


Electric cars are more expensive tomake and maintain, and don’t offer any additional utility. So it works for me if foreign countries ban petrol. Lower oil consumption means cheaper gas. And cheaper gas means we’re spending less money for the same utility as other countries. More competitive advantages.

The future is renewable energy eventually. Solar in particular, as the others just don’t scale. But that time is a few decades off. For now, coal and ng rule and nothing is going to replace them. There’s just no reason to spend trillions of dollars converting from coal to solar. When solar becomes cheaper, of course it makes sense. That will be a long time from now.


That’s true of any burgeoning technology, what matters is, will that always be the case?

As far as maintenance?

When we eliminate the parts that petrol and electrics have in common, I’d disagree. Electrics have fewer moving parts and fewer parts that “rub together” causing friction.

Right now, the biggest technical challenge is batteries. There are more efficient ways to store energy on the horizon and when companies see the increase in market share, money dedicated to development will increase increasing efficiency and decreasing costs.

Simple economics will drive the demand for electrics eventually as they will simply be more cost effective to own and operate.

Sure they do. If you have solar at home you can charge your car each night. Electric motors are much more efficient than gas engines as they supply of there power and torque from the moment you step on the “gas” (a term that will die hard).

They make less noise

The gas station will disappear, there will be charging stations in the same places you park.

Zero emissions from the car itself meaning that places, where there are lots of cars, will be cleaner.

The actual amount of emissions will depend on the sources of electricity, but finding technical solutions to containing pollution in 100’s of power plants (that emit pollution) is much easier than trying to control emissions from 100’s of millions of cars.

Increased power for less money. Today the P100D is the fastest non-modified production car built even when accounting for cost. With perhaps the exception (arguably) of Chystlers street legal dragster, which has very, very little utility compared to the P100D.

You operate on the assumption that oil supply will remain the same. The economy of scale will work backward as demand falls. Meaning each unit of oil will increase.

It also makes the assumption that electrics, like other new technologies, won’t decrease in price over time. VCR’s, LCD’s, computers, cellphones? Really?

Remember that to get about 280 miles of range in a Tesla P85D (a car I have stats for) costs less than $9 at about.11 cents /kWh.

Even if fuel decreases in cost, the demand for electricity has the potential for decreasing the cost via economies of scale and increasing efficiency of renewables.

By 2040 at least 1/4 of the world’s population will live in places where electrics are the only choice. Other nations near China will be heavily influenced and I suspect that 1/3 of the world would live in places where electrics are the only choice.

That will drive innovation in the methods used to create the energy to supply them and lower the cost. Now having said that, I think sheer economics will be in play. Coal and NG and oil will simply be more expensive and financial decisions not political ones will drive the markets. The only real question in my mind is will the US lead or follow. Given the dogmatic devotion to oil, coal, and NG, it’s looking like follow.


If your argument is “Some day, something will replace combustion engine cars”, then of course. But if your argument is “In the next 20 years, electric cars will be cheaper and better than combustion engine cars” I am extremely skeptical. It’s possible of course. But it’s not likely.

I’ve been extremely skeptical of a lot of hot new technology that amounted to nothing. I was practically a one man force on my team beating back suggestions that we recommend stores outfit their facilities with iBeacons.

MOST new tech dies. Why did dvds replace vhs? They were: higher quality picture, cheaper to make and buy, smaller and easier to store, and allowed easier skipping and no need to rewind tapes.
How many potential VHS killers were there? Betamax, laser discs, and a host of crap you probably haven’t even heard of. None of them were much better.

Has BluRay replaced dvd? Nope, it still hasn’t. Dvds are over 80% of movie sales. Why? Because blurays lack 3/4 components. Yes, they have higher quality picture, but they’re more expensive, they’re identical in terms of storage space, and aren’t especially more convenient.

HDTVs did not become the norm until they were priced under $500. And they too had numerous advantages. They were higher quality, usually larger, and until they were only moderately more expensive they didn’t become mainstream.

I’ve been in tech for a while… and I remember many, many industry experts back in the early 2000s predicting that by 2010 pc and laptop sales would be smaller than tablet sales. That never happened and I knew it never would. To what limited extent people are now buying tablets, they buy them as a portable movie device and gaming system. They’re not replacing computers, they’re replacing Play Station Portable. And the tablets being sold aren’t power tablets for $300+. They’re cheap Amazon tablets for $50.

I almost never see a new technology displace an old technology unless it is MUCH better. Electric cars are not only not much better, they’re actually worse than traditional cars. Maybe in 20 years they’ll be better and cheaper. Maybe tablets will still replace pcs and laptops. But I certainly wouldn’t bet on it. And I certainly wouldn’t bet my entire community’s future on it.

For longevity…


No, that’s not my argument.

Electric cars, despite your numerous instances of examples of failed tech (sort of a trip down memory lane as I am also in the tech business) electric cars aren’t a novelty. They are here to stay. Now, how long before there are more electrics than petrol engines…That’s a good guess, but if I were a betting man, I would bet sooner than “someday”.

Interestingly according to consumer reports:

Despite these problems, CR reports that Tesla owner satisfaction is still very high, with a full 97 percent of owners [1,600+ owners survated] saying they would definitely buy their car again. Surveyed owners also commended Tesla’s quick response when cars developed problems: “Almost every survey respondent made note of Tesla’s rapid response and repair time, despite the lack of a traditional dealer service network.”

Few thoughts on your other comments:

Killers? I’d call most of those competitors as they are all developed about the same time. VHS started development about 3-4 years before laserdisc and it was thought for a long time that VHS would never reach the consumer level because of how quickly the tape had to be dragged past the read/ write head. Just a few minutes of video would take 1000’s of feet of tape. a problem that was considered insurmountable until the invention of the spinning tape head.

The death of Beta had as much to do with industry alliances as anything else.

Not sure what you mean when you say the “lack 3/4 components”.

As far as storage space., DVD’s hold 4.3gb and Duel layer Blu-ray disks hold more than 10 times more or about 50gb. Even a single layer disk (used for most movies) hold 25gb.

However, there are some Blu Ray disks that hold more than 2 layers, some up to 16, but the players for those are different than average consumer devices.

As far as sales figures, I don’t think the raw numbers tell the story. DVD’s are cheap, but steaming is killing both formats, especially Blu-ray. If you can afford the TV to watch it on and the player to play it and the format itself, chances are you can afford to have a broadband connection wide enough to stream high bandwidth content from the internet. It’s more convenient and allows you to watch movies from multiple devices.

There we can agree.

They will and if companies like GM want a piece of that action, they better start working on the R&D yesterday.

With respect to the article.

the survey size was 327 people. A rather small sample size, however, I’m not suggesting that’s insignificant. Interestingly though, the article correct itself stating that the motors didn’t fail, rather some began making noise and were proactively replaced.

As far as being better, the biggest complaints I’m aware of from my 3 friends that own Tesla’s is the lack of charging stations and the time it takes to charge if the cars run out of juice. However, they point out the only time that waiting to charge becomes a real issue is if they are driving more than the car can go on a single charge in a single day as they all charge their cars at home overnight and if they travel, find the car is usually good for several days before charge becomes a real problem. How often does the average eprson travel more than 250 miles in a day?
They rave about the other convinces that cannot be found in any other car at its price point. They also give Tesla service 11 stars out of 10. Not to mention is’s mind numbingly fast (if you own the D) if your into that sort of thing.

To each there own I guess.

I just bought a car and considered an all electric, but I would tend to agree, the maturity and competition isn’t there yet. I’ll probaly keep my current car 6-7 years and imagine that by then there will be several viabile opinions. Time will tell.


The four things that allowed dvd to replace VHS. Bluray only has superior image quality. It isn’t cheaper, it isn’t physically smaller to store, and it’s not more convenient(dvds already have chapters, skip to X minute, etc which VHS obviously did not have). It would probably have needed at least 3 of those things to replace it.

Streaming is winning because it’s cheaper, and more convenient. Its main limitation is lack of universal content. If you had every dvd movie on Netflix, dvd sales would be nearly zero in a couple of years.

But none of those things have anything to do with an electrical engine. You could slap literally any of those features in a car with a combustion engine.

Nah, I’m not really into the D :stuck_out_tongue:


Ahhh…I see, not enough innovation. I can agree with that.

I will argue that it could be made much smaller and hold the same content as a DVD, but size really isn’t that big an issue. Another thing you forgot is that Blue-Ray is less prone to scratching and hold a lot more content, but I take your point.

As far as the Electric engine vs the Petro engine, let’s see if I can come up with some significant advantages and you tell me what you think.

Despite Tesla’s implementation, Electric motors have better reliability.

Electric motors have much greater efficiency as they have fewer moving parts and do not waste as much energy in friction (80-90% compared to 20-30% for ICEs).

Electric motors don’t require a car to have a transmission at all. Thus, have a very wide range of operating speed, so need no gears, or fewer gears, to move through their full speed range

Electric motors have full power and torque available through their entire range (just another aspect of efficiency)

Use less energy (largely the result of fewer friction losses).

Oh, and it makes less pollution at the source.


The greatest limitation IMO is that range is limited when normalized for the cost.

Lack of charging infrastructure

Widespread adoption of electrics will put intense pressure on the supply of lithium.