It's 2020. SF to LA for $25 on Elon Musk's Hyperloop - Are you buying it?

[PlainName]

but you missed the point of his vide

I don't think so. I am sure he achieved what he set out to do.

I have been on that train that runs under the English Channel and couldn’t see any fish out the window.

And yet there are windows. So perhaps having windows doesn't invalidate the entire tunnel design after all, eh.

Another is it didn’t transport the riders anywhere.  They got on, where they got off.

Sorry, you've lost me there - should they have been made to walk back or something?

[EEVblog]

The Hyper-loop test was a scam.
https://youtu.be/VrbstnzbhZA

I don't read eevblog to follow youtube links. If you can't take the time to present whatever argument you believe from the video, you'll just have to fail to communicate.

You are free to ignore all video links, you don't have the click on them.
Going out of your way to tell everyone that you don't follow video links says more about you than it does the person posting the link.

[EEVblog]

I don't see any technological reason that the hyperloop could not be implemented, but to say that I'm skeptical of it ever being practical or economical would be an understatement. I just don't see much advantage over traditional high speed rail. It could be faster for the energy used, but any savings are likely offset by the much higher cost of the construction and maintenance.

^^^ This.

[wraper]

The Hyper-loop test was a scam.

https://youtu.be/VrbstnzbhZA

Frankly that video consists from a lot of rambling and barely any proof it's a scam. Same information could be easily presented in less than 5 minutes instead of 25.

[hans]

I think thunderf00t's sceptism is well in place. I don't really care that much about the speeds this test run has achieved.. that's a limitation of the test track length and reasonable acceleration forces. It's hilarious, that's all. But the whole look and feel of the program is so dumbed down. Look, we have a pod in a tube and it moves! Okay, and what about the rest? So many key points or details unanswered..

I think the potential hazards of a sudden decompression are real. If a tree or some other big object (helicopter, recreational airplane, etc.) falls onto a hyperloop, is it going to suddenly decompress? What is going to happen with the pods in that section of the loop? Is it technically even *feasible* to create multiple vacuum sections for added safety? Are there vacuum doors that can seal well and fast enough for pods to enter the hyperloop or sections of loop? What if those doors fail? Are suddenly all pods of the loop in danger because of a vacuum leak?
I haven't seen any mention of doors. There is freaking train track *inside* the door after all. Maybe a small section of discontinuity is fine for the pod near a station.. but maybe it is not at full speed.

Then is the potential energy of the created vacuum. Just look at the scale of those numbers; multiply them by 10s or 100s of km and you have a ticking bomb on the ground. For that reason I'm actually quite happy planes fly at >30kft. If an airframe decompression happens at that altitude, pilots will deploy oxygen masks and descend the plane rapidly to 10k ft or so to regain a survivable atmospheric pressure. (See Helios Airways Flight 522 to read what happens if you don't). What's the backup plan in a hyperloop if the loop or a pod suddenly decompresses? I can't think of many options. Are passengers going to be stuck on that journey (possibly with an oxygen mask)? What if some passengers didn't get the mask-memo and are unconscious after 30 seconds for the whole journey? Normally I'm not claustrophobic, but I think many people would suddenly be in that case..
That is... assuming that oxygen masks even work. After all we're in a near complete vacuum. Maybe people will just die within a few seconds because your body cannot contain the air within your lungs because of the expansion. I wouldn't get into a hyperloop if it doesn't have multiple redundant backup systems to be honest..

I think that latter point is alone to be skeptic about the Virgin test being actually performed at low pressure. Have they put those redundant safety systems in place at the test loop? Or have they tested without them, risking the lives of their highly positioned staff of the hyperloop project? Doubtful.

[Nusa]

You are free to ignore all video links, you don't have the click on them.
Going out of your way to tell everyone that you don't follow video links says more about you than it does the person posting the link.

Fair point. I allowed myself to become annoyed. Usually I am more tolerant.

[EEVblog]

I think thunderf00t's sceptism is well in place. I don't really care that much about the speeds this test run has achieved.. that's a limitation of the test track length and reasonable acceleration forces. It's hilarious, that's all. But the whole look and feel of the program is so dumbed down. Look, we have a pod in a tube and it moves! Okay, and what about the rest? So many key points or details unanswered..

I think the potential hazards of a sudden decompression are real. If a tree or some other big object (helicopter, recreational airplane, etc.) falls onto a hyperloop, is it going to suddenly decompress? What is going to happen with the pods in that section of the loop? Is it technically even *feasible* to create multiple vacuum sections for added safety? Are there vacuum doors that can seal well and fast enough for pods to enter the hyperloop or sections of loop? What if those doors fail? Are suddenly all pods of the loop in danger because of a vacuum leak?
I haven't seen any mention of doors. There is freaking train track *inside* the door after all. Maybe a small section of discontinuity is fine for the pod near a station.. but maybe it is not at full speed.



Then is the potential energy of the created vacuum. Just look at the scale of those numbers; multiply them by 10s or 100s of km and you have a ticking bomb on the ground. For that reason I'm actually quite happy planes fly at >30kft. If an airframe decompression happens at that altitude, pilots will deploy oxygen masks and descend the plane rapidly to 10k ft or so to regain a survivable atmospheric pressure. (See Helios Airways Flight 522 to read what happens if you don't). What's the backup plan in a hyperloop if the loop or a pod suddenly decompresses? I can't think of many options. Are passengers going to be stuck on that journey (possibly with an oxygen mask)? What if some passengers didn't get the mask-memo and are unconscious after 30 seconds for the whole journey? Normally I'm not claustrophobic, but I think many people would suddenly be in that case..
That is... assuming that oxygen masks even work. After all we're in a near complete vacuum. Maybe people will just die within a few seconds because your body cannot contain the air within your lungs because of the expansion. I wouldn't get into a hyperloop if it doesn't have multiple redundant backup systems to be honest..

I think that latter point is alone to be skeptic about the Virgin test being actually performed at low pressure. Have they put those redundant safety systems in place at the test loop? Or have they tested without them, risking the lives of their highly positioned staff of the hyperloop project? Doubtful.

That's what so many people either don't get, or choose to consciously ignore in pursuit of "the dream".
Many will compare them to planes, but what they don't realise it's actually opposite. If a plane decompresses then oxygen drops and it trivial to drop to safe altitude in time. Proven and foolproof in a small tube.
But with the Hyperloop you are trying to keep out pressure instead of keeping it in, in tubes hundreds of km long. A big failure doesn't mean decompression, it means implosion of some description.  The entire concept of making it work is practical insanity and doomed to failure.

[wraper]

A big failure doesn't mean decompression, it means implosion of some description.  The entire concept of making it work is practical insanity and doomed to failure.

All those examples of implosions and comparing them to Hyperloop are non informative BS to be frank. Imploding some tank which was designed to hold the pressure inside is not an indicator of how a properly designed vacuum container would perform. Say usual submarines operate at outside pressure of 30 times higher than atmospheric and nothing implodes. And deep diving submersibles with humans inside operated even at more than 1000 times of atmospheric pressure.
EDIT: and the pod is not much different from an airplane cabin at high altitude.

[madires]

Nope, but you can buy tickets for ICE, TGV, Shinkansen or other high speed trains which are running fine for decades.

From https://en.wikipedia.org/wiki/High-speed_rail:

On 23 October 1903, the S&H-equipped railcar achieved a speed of 206.7 km/h (128.4 mph) and on 27 October the AEG-equipped railcar achieved 210.2 km/h (130.6 mph).[6] These trains demonstrated the feasibility of electric high-speed rail; however, regularly scheduled electric high-speed rail travel was still more than 30 years away.

And Hyperloop thinks that 100 mph are an achievement in 2020?

[DougSpindler]

The Hyper-loop test was a scam.

https://youtu.be/VrbstnzbhZA

I don't read eevblog to follow youtube links. If you can't take the time to present whatever argument you believe from the video, you'll just have to fail to communicate.

Sad you don’t watch any of Dave’s videos. They are very good.  I’ve learned a lot from Dave’s videos as well as other videos posted by others.  You might want to give watching videos a try before you die.  You might learn something.

That would be an invalid leap of logic, which doesn't surprise me. Not following blind forum video links to lengthy videos that rarely are worth watching does not mean I never watch videos. I do follow various channels from a proper interface where I can see the author, title, date, and length BEFORE I choose to view them now, later, or never.

Now if you weren't someone with a history of linking videos instead of using words and the video had a proper summary of something that interested me greatly, that might be another story.

Dude sounds like you are part of the vacuum tube generation.  Time to get with all of the new technology. YouTube is filled with excellent videos from very credible sources.  The material can be explained far more accurately and in greater detail in a video.  I’d sure like to see a paper teaching someone how to solder.  In a video the concept can be clearly explained in 5 minutes.

Yes there is a lot of noise on YouTube, but dang dude, why would you not watch the videos I posted from Sandy, Dave and others. Why would you want to spend hours reading Sandy’s 150 page report on Tesla when you can watch his 15 minute video and get to see exactly what he is talking about.  I’m not posting links to shitty videos.  But I sure have seen links posted here on bogus papers.  Crap on how bio-fuel is carbon neutral.  Or that the Great Barrier Reef is dying.  Or the total BS claim man caused climate change isn’t happening.  Were some of those your posts?

[sandalcandal]

Maybe a more condensed objective view. The main challenges in a hyperloop system currently seem to be:

• Safety
• Pod Decompression
• Tube Decompression
• Escape
• Reliability
• Partial Vacuum Maintenance
• Cost effectiveness
• Achieving the above with cost-benefit attractive compared to existing solutions

Each of those key points can be broken down into much finer points but the above give an overview of the major unique challenges for a hyperloop system to be practical.

Virgin Hyperloop Demo

The demo by Virgin Hyperloop shows that they are capable of building a maglev train capable of carrying people in a tube evacuated to 100 Pa [see above video description]. I don't think whether or not a maglev train with a passenger pod running in partial vacuum tube can be built at such a small scale is a major question but the competency to do so is at least a minimum requirement. So as Thunderfoot also said, good on them for at least achieving that. However, I don't see any breakthroughs or innovations as far as addressing the main issues. The tubes shown in the Virgin Hyperloop Demo look like conventional pressure vessels/pipes with conventional fittings, their work so far has been to attach rails and LED lights to the interior of the pipe and make a passenger pod.

Cost
I'll get keen if I can see some evidence of developments which actually solve the main challenges. Perhaps some modular track system with associated mass production facilities; an array of highly DFM optimised tube sections which can be bolted together to enable all required functions including terminals, vacuum maintenance, emergency escapes and just curved sections (only straight sections so far). Whether or not the track system can be cost optimised to a point that the additional cost of the enclosing tube beats running costs and performance limits of existing maglev and air travel is the most important question imo.

Safety
A means of automatic, high-reliability isolation of breached sections would be an important innovation to improve reliability and safety. Such a system might also be able to dump air into the beached section to remove pressure differential for best safety.

Partial Vacuum Maintenance
I don't think creating and maintaining the vacuum itself in terms of sealing and leakage is going to be big issue given we already have similar and matured technology in the form of gas transmission pipelines. Gas lines already criss-cross the country and operate in excess of 10x the pressure differential (1050 kPa) of a Hyperloop with very tight leakage allowances since they of course contain explosive gasses. Had a gander in AS 2885 (the Australian Standard of gas and petroleum pipelines) and pipes are meant to be "leak tight" but permit an "allowable fluid variation" of 400 L/24 h for undeveloped rural land down to 20 L/24 h for high density in pipe volumes up to 25 ML. Maybe someone with a mate in the gas industry can comment?

Vacuum Structural Concerns
Decompression and vacuum pressure are also not the biggest issues. Even in Thunderfoot's video he goes to great pains to ramble about how a pressurised pod is no different to a plane cabin for the most part. Implosion wouldn't be a major failure mode, the tubes are under pressure all the time, if anything a local failure results in less stress on the tubes not some runaway implosion Videos you've seen of tankers or barrels being imploded are not analogous, those are vessels designed for a completely different load being subjected to the inverse of that load. Since vacuum vessel walls are in compression rather than tension they need to be designed to resist buckling, that's why vacuum hoses are typically ribbed. The buckling failure mode you see in tanker implosions are not a relevant concern for a properly designed vacuum vessel. It's like being worried about steel I-beams being weak because steel cable bends so easily when you compress it different loads, different design optimisations. The actual stresses are much lower than most pressure vessels due to an absolute limit of pressure at 1atm but the tangential area moment of inertia needs to be bigger to prevent buckling (hence ribbing).

On that point about structural design of tubes, I'm surprised no one has presented anything like a ribbed or thick-walled tube structure or even a double cylinder similar to the "double bubble" fuselage like the Aurora D8 (https://youtu.be/H7Z04Tl1-1Q) or maybe they have and it hasn't cross my field of view yet. Would be nice to see a video or article which sums up the different companies and their innovations if any.

I've given some counter arguments to points people have raised against a Hyperloops but don't take that to mean I think they're a practical idea. I've started this off by offering my take on the main issues the concept faces and provided a constructive take on what I want to see done. I also don't see Virgin Hyperloop or any of the other Hyperloop startups as yet being likely to succeed. What I don't agree with is some of the poor reasoning and sources presented. Thunderfoot is especially guilty of this, citing and responding to incorrect second-hand and in many cases MSM sources targeted at a general public lay audience then critising it for lack of technical rigor might as well be straw manning e.g. Thunderfoot claims that Elon claims to have invented the hyperloop by playing second-hand sources to build his strawman then attacking it by saying Robert Goddard came up with the idea first when the truth is in the original paper (first-hand source! if you think its edited archived source) they literally, explicitly credit the idea of trains in vacuum tubes to Robert Goddard, Rand and ET3. You should realise he's playing anti-Musk sentiments for views, he makes videos aimed to stroke outrage not provide information. If you want to actually examine an idea for its merit then examine the actual idea not some crappy clickbait trying to sponge hype for views i.e. look at the original paper or other first hand sources by the companies working on the idea. That being said I'm sure some of you are here to just circlejerk about how some rich people are wasting money and not to do any meaningful "debunking". No complaints about most of the debunking videos I see Dave do, they are normally at least examining first-party claims but Thunderfoot is a farce. I don't want to see you BSing yourself into trying to get an easy takedown.

Edit: As for the concern that air leaking into the tube would cause any danger I don't know where that's coming from but that'll just cause drag and make the train operate at a lower speed or the train can otherwise initiate breaking as per the original paper or other videos (less "bearish") videos about hyperloop. The original paper also has full details of the proposed workings of the hyperloop including safety measures and quantified technical details, don't listen to Thunderfoot's alternative reality strawman hyperloop 

[wraper]

I had some thoughts about stations and came to conclusion it's not that big of a problem at all. Sealing of the tube can be done just as on the video. And stations just as usual train stations. People board the train just as in usual station. Then train enters a short section of tube, then a section of rail is retracted sideways (proven technology) to clear obstruction, then tube opening is closed just as on the video. On the other end of this section is a somewhat wider chamber with the same method of sealing and the same retractable rail. Once train enters and tube is sealed from the outside, air is pumped out, internal seal opens, rail is moved, train passes further, rail is retracted, seal closed. And train can move forward normally.

[PlainName]

That - sandalscandal's take - is the kind of  examination I could read all day. Well, the minute or so it actually took. It will be a sad day when he discovers 25-min ad-supported video.

One thing I'd take issue with, though, is cost. It is fine to say, "Blimey, that's jolly expensive" but we aren't investors and we're not paying for it. Surely, the fact that someone is coughing up means it's affordable to them.

[wraper]

Even in Thunderfoot's video he goes to great pains to ramble about how a pressurised pod is no different to a plane cabin for the most part. Implosion wouldn't be a major failure mode, the tubes are under pressure all the time, if anything a local failure results in less stress on the tubes not some runaway implosion Videos you've seen of tankers or barrels being imploded are not analogous, those are vessels designed for a completely different load being subjected to the inverse of that load. Since vacuum vessel walls are in compression rather than tension they need to be designed to resist buckling, that's why vacuum hoses are typically ribbed. The buckling failure mode you see in tanker implosions are not a relevant concern for a properly designed vacuum vessel. It's like being worried about steel I-beams being weak because steel cable bends so easily when you compress it different loads, different design optimisations. The actual stresses are much lower than most pressure vessels due to an absolute limit of pressure at 1atm but the tangential area moment of inertia needs to be bigger to prevent buckling (hence ribbing).

Yes, it's like taking a bridge, turning it upside down, then rambling that bridges are impossible because they fall apart.

[Domagoj T]

Edit: As for the concern that air leaking into the tube would cause any danger I don't know where that's coming from but that'll just cause drag and make the train operate at a lower speed or the train can otherwise initiate breaking as per the original paper or other videos (less "bearish") videos about hyperloop. The original paper also has full details of the proposed workings of the hyperloop including safety measures and quantified technical details, don't listen to Thunderfoot's alternative reality strawman hyperloop 

IIRC In an earlier video Thunderfoot's concern was that in case of a catastrophic breach of tube (for example a truck crashing into it, or sabotage) where air can freely enter the tube, you get an inrush of air at about the speed of sound which will turn any capsule it encounters into a bullet.

[wraper]

Here I visualized how train could enter the tube. Nothing extraordinary.

[sandalcandal]

Made myself watch OP Thunderfoot video https://youtu.be/2h6Cz4hwuEI despite his annoying schoolboy attitude and I've made some notes on what his actual points are between the rambling and attempted rage baiting

• 0:00-2:05 Lots of money has been spent/invested but no working system yet
• 2:05-5:15 Theranos tangent and likeness citing second-party claims (no actual arguments)
• 5:15-7:20 Elon Musk stole the vacuum tube train idea from Robert Goddard
• 7:20-8:00 Previous vacuum train ideas were impractical
• 8:00-9:00 Empty straw manning
• 9:00-11:35 Boring Company City Loops
• 11:35-13:29 Lack of Progress
• 13:29-14:23 Air bearings
• 14:23-23:35 Slow Progress
• 23:35-24:20 Videos Videos
• 24:20-25:21 Boring Company Loop outro

1. Lots of money has indeed been invested into companies working on hyperloops with grand promises but nothing delivered. Not starting with a lie afaik.

2. Theranos is indeed a well known fraud. If you want an actual informational video about Theranos I recommend https://youtu.be/3CccfnRpPtM and https://youtu.be/qUFHEZOfQ0k However, immediately associating it with hyperloop is a hasty generalisation probably designed to immediately cast the subject in a poor light to help setup the rest of his rant. Throughout the video he likens Musk to Elizabeth Holmes as though he's some how getting rich off the idea and investment money going into it  in case you don't know he has no active involvement beyond SpaceX running the Hyperloop pod student competition.

3. Thunderfoot's assertion Elon Musk stole the credit for the vacuum tube train idea from Robert Goddard Completely false, as per my previous post, the original paper specifically credits the idea of vacuum tube trains to Robert Goddard, Rand and ET3.

Many ideas for a system with most of those properties have been proposed and should be acknowledged, reaching as far back as Robert Goddard’s to proposals in recent decades by the Rand Corporation and ET3.

3/4. "There is absolutely nothing new or novel about the concept of the Hyperloop"-Thunderf00t. The original paper attempts to propose meaningful changes to the concept to make it feasible not that Thunderfoot would let the truth get in the way of a good non-factual rant. A key point made in the paper is that hard vacuums proposed in previous iterations are impractical and difficult thus a low vacuum system should be used rather than a hard vacuum.

The problem with this approach is that it is incredibly hard to maintain a near vacuum in a room, let alone 700 miles (round trip) of large tube with dozens of station gateways and thousands of pods entering and exiting every day. All it takes is one leaky seal or a small crack somewhere in the hundreds of miles of tube and the whole system stops working.

The main changes to the vacuum train concept which the Hyperloop proposes are: low pressure instead of vacuum, electric fan compressor to overcome Kantrowitz Limit, above ground pylons with heavy prefab for cost and pylon design+telescoping sections for earthquake resistance and PV for self-power.

5. Nothing of substance here from Thunderfoot, just straw manning and made up delusions. The original paper has detailed cost estimates with breakdowns but any actual analysis or discussion of those numbers are probably beyond the target audience or presenter.

6. Thunderfoot gives no basis for his deluded claims again straw manning AND makes a false analogy by saying two superficially similar concepts are fungible. The Hyperloop is meant to solve high speed regional travel and thus requires very high speed achieved through partially evacuated tubes. The Boring Company and associated Loops are meant to solve congestion in high-density American cities, that's why they're underground instead of on pylons like Hyperloop, the main competition of the Boring Company tunnels is flying cars

7. Not much substance or analysis here Thunderfoot just playing clips from MSM  Also not much substance from here on.
8. New third party commercial designs don't use the fan or airbearings which isn't a lie afaik. Keep in mind the original paper also uses maglev for propulsion, the fan is for over coming the Kantrowitz Limit at high speed.
9. He's just repeating: Nothing meeting end goals has been done yet
10. This part should tell you his real motivation, its a topic that generates lots of views.
11. Ending on an outro showing a completely different product. Again, should show you how much analysis and research he's actually done 

Shallow intellectualism and outrage bait masquerading as "debunking" is what the video is. Just as bad as the MSM videos he pretends to "debunk". Makes me want to puke! 
The video starts with factual BULLSHIT for the first half, followed by 15 min of irrelevant crap and repeating "there's nothing here yet". There is absolutely no content of value here, no insightful let alone honest investigation of the topic, just deceitful outrage stirring. He starts you rolling with manufactured lies followed by "oh they haven't done it yet [so clearly they never will]"  for 15 min All his "debunking" for this topic is half-truths at best and straight lies designed to stir you up. This message which he plasters in your face at the start of the video:

is a lie.

Now I'm not saying all his videos are lies, honestly with the low hanging fruit he normally goes for it's hard to be "wrong". I also don't personally see Hyperloops becoming practical and in-use in the next 20 years let alone on the timelines companies are claiming. There's definitely lots of issues for Hyperloop to be practical and the original paper certainly doesn't have all the answers. I definitely don't see any current companies being on a fast rack to success. But for the love of God don't get your news and opinions from Thunderf00t videos, they're outrage videos not investigative news or analyses. If your idea of a good time is having your jimmies rustled then feel free to "enjoy" his content but if you want factual information then shut it out. 

Edit: Saw his 2016 video on the Hyperloop, a lot better than the latest two, not nearly as trashy. I wonder what happened? 

[bson]

If a tree or some other big object (helicopter, recreational airplane, etc.) falls onto a hyperloop, is it going to suddenly decompress? What is going to happen with the pods in that section of the loop?

The entire section will have to be pressurized, assuming there are locks between sections that permit doing so, otherwise the whole system will need to be pressurized.   It's just a matter of having enough valves to prevent explosive repressurization.  But Thunderfoot is right in comparing it Fyre Festival - it's just not possible within the financial envelope imagined.  Also, forget about 600mph, it's not just about air resistance but sheer kinetic energy, but maybe it will run at 300mph, so a little bit faster than CAHSR (where it will be able to actually go that fast, meaning outside urban areas).  That's still not competitive with flying, meaning people who travel for business won't use it (at least not if they value their time).  The routes and capacity will preclude solving the real traffic problems, which is 99% work commuting and requires LOCAL transit, not a SF-to-LA "vacation line".  For vacation travel BTW, run it to Las Vegas.  In other words, a casino train.  THAT I think would be marketable.  Still, not economical, but at least it would find an audience.

[wraper]

Also, forget about 600mph, it's not just about air resistance but sheer kinetic energy, but maybe it will run at 300mph, so a little bit faster than CAHSR

What's wrong about kinetic energy and why should it limit the speed? Air resistance? It's specially made to avoid air resistance.

CAHSR

More like CRAPHSR

[sandalcandal]

Edit: As for the concern that air leaking into the tube would cause any danger I don't know where that's coming from but that'll just cause drag and make the train operate at a lower speed or the train can otherwise initiate breaking as per the original paper or other videos (less "bearish") videos about hyperloop. The original paper also has full details of the proposed workings of the hyperloop including safety measures and quantified technical details, don't listen to Thunderfoot's alternative reality strawman hyperloop 

IIRC In an earlier video Thunderfoot's concern was that in case of a catastrophic breach of tube (for example a truck crashing into it, or sabotage) where air can freely enter the tube, you get an inrush of air at about the speed of sound which will turn any capsule it encounters into a bullet.

That would require a shockwave breech to in order occur. Any breach is going to have a flow rate limited by the size of that breach. That limited flow rate needs to gradually fill the entire volume of this km long pipe. The fact it's coming in at the speed of sound matters much less than the rate mass is coming in. It's not like a breech is going to result in pods hitting a 1 atm wall of air at the speed of sound, unless its a massive breach like an entire section sheared clean off which is highly unlikely to occur from a truck somehow flying up to the tube on top of a pylon and getting a clean cut. Perhaps if some terrorists try to blow a section up?

Vacuum gun experiments use a bursting disc to trigger a shockwave onto a very light, well-sealed projectile in a very long tube. This is what a less professional/ideal vacuum gun does https://youtu.be/bAKqzAzfXKQ?t=430 Given most recent designs seem to forfeit the tight sealing idea for no compressor and more open space that seems even less likely to be a catastrophic issue and would be even less with automatic isolation as I'd like to see.

Edit: His attempt at a vacuum failure demo is pathetic, you could blow a ball out of a tube harder than that, I wonder if you'd get a stronger effect from just tilting the tube down. You can hear the rush of air flowing in "gradually" compared to the shockwave bang in purpose designed vacuum guns.
Edit2: I'll admit I wasn't aware of this vacuum gun concern before hand.
Edit3: I'd be a lot less displeased if that first 2016 video was the only point of discussion.

[DougSpindler]

Here I visualized how train could enter the tube. Nothing extraordinary.

That might work on paper, but not in the real wold.  Have you ever worked with vacuum chambers? 

Something else not sure is Thunderf00t mentioned is what happen at thar speed in the capsule hits a object say the size of a grain of sand or a paint chip?  That would easily puncture the capsule leading to immediate depressurization of the capsule.  Within 30 seconds or so they would be dead.

Guess we could use something like armor platted capsules which might work.  But then that will sure add to the cost of propelling the capsule.   

[Nusa]

Here I visualized how train could enter the tube. Nothing extraordinary.

That might work on paper, but not in the real wold.  Have you ever worked with vacuum chambers? 

Something else not sure is Thunderf00t mentioned is what happen at thar speed in the capsule hits a object say the size of a grain of sand or a paint chip?  That would easily puncture the capsule leading to immediate depressurization of the capsule.  Within 30 seconds or so they would be dead.

Guess we could use something like armor platted capsules which might work.  But then that will sure add to the cost of propelling the capsule.

It's called an airlock, something that works quite well in the real world. Additionally, we're not talking hard vacuum, but a more practical low pressure.

As for a object that small hitting a capsule in space, we do know what happens and how to deal with it, but that's irrelevant. We're not talking the kind of speed differentials you find in space. We're talking airplane speeds, and airplanes shrug off the small stuff all the time. Large birds can be dangerous, but we won't find any of those in the tunnel. Your scenario isn't realistic.

But in the event of leaks, there are a number of solutions already thought of, depending on the severity of the problem. Maybe you should read Musk's original paper on the subject. You'd get more basic facts right.

[wraper]

Something else not sure is Thunderf00t mentioned is what happen at thar speed in the capsule hits a object say the size of a grain of sand or a paint chip?

It's not a speed of satellite in space for grain of sand to puncture anything. You need more than order of magnitude higher speed for it to puncture anything. Nor a small hole is enough for rapid depressurization. I can mention ISS as example, they have a small hole from space debris collision from time to time. Nor all of the air got away, nor anybody died. As of what happens at depressurization, obviously there should be safety valves on the tube to let the air in in case of emergency. FYI at 12 km altitude (39k ft) where passenger planes are flying, atmospheric pressure is below 0.2 atm (instead of 1 atm at sea level) which is almost vacuum as far as human organism is concerned and you will lose consciousness if do not put an oxygen mask on your face within a few seconds.

[EEVblog]

A big failure doesn't mean decompression, it means implosion of some description.  The entire concept of making it work is practical insanity and doomed to failure.

All those examples of implosions and comparing them to Hyperloop are non informative BS to be frank. Imploding some tank which was designed to hold the pressure inside is not an indicator of how a properly designed vacuum container would perform. Say usual submarines operate at outside pressure of 30 times higher than atmospheric and nothing implodes. And deep diving submersibles with humans inside operated even at more than 1000 times of atmospheric pressure.

Those vacuum containers aren't hundred of km long. Good luck.

[EEVblog]

The demo by Virgin Hyperloop shows that they are capable of building a maglev train capable of carrying people in a tube evacuated to 100 Pa [see above video description]. I don't think whether or not a maglev train with a passenger pod running in partial vacuum tube can be built at such a small scale is a major question but the competency to do so is at least a minimum requirement. So as Thunderfoot also said, good on them for at least achieving that. However, I don't see any breakthroughs or innovations as far as addressing the main issues. The tubes shown in the Virgin Hyperloop Demo look like conventional pressure vessels/pipes with conventional fittings, their work so far has been to attach rails and LED lights to the interior of the pipe and make a passenger pod.

And that's marketing trickery 101. They'll milk it for years.