The Hyperloop: BUSTED

[wraper]

Let's say they can travel at 1000km/h. The tubes have to be safe. There has to be a safe distance between tubes so a crash in the Up tube can't take out the Down tube. A safe separation may be 100 meters. That is not the worst part. It has to be safe for people in the proximity of the tunnels. A safe distance exclusion zone could be 400 meters? I do not know but we are talking  a possibility of a big high energy collision with shrapnel - it could be 1 km or more. So when they build the London to Edinburgh hyperloop that they talk about, are they going to build a corridor 2 km wide all the way through the heart of England? Even putting the tubes in trenches will not stop shrapnel flying for massive distances.

Talking about putting solar cells on top of the tunnels is a total joke if you are going to have 1km each side unoccupied.

Safe distance, LOL? By same merits, you would need to keep people away from usual high speed train at least a few km away as well 

How much kinetic energy can a loaded shipping container have at this speed? The vehicle will probably have to have at least the mass of the heaviest container.

FYI due to much smaller size, kinetic energy will be lower than of usual high speed train.

[amspire]

Let's say they can travel at 1000km/h. The tubes have to be safe. There has to be a safe distance between tubes so a crash in the Up tube can't take out the Down tube. A safe separation may be 100 meters. That is not the worst part. It has to be safe for people in the proximity of the tunnels. A safe distance exclusion zone could be 400 meters? I do not know but we are talking  a possibility of a big high energy collision with shrapnel - it could be 1 km or more. So when they build the London to Edinburgh hyperloop that they talk about, are they going to build a corridor 2 km wide all the way through the heart of England? Even putting the tubes in trenches will not stop shrapnel flying for massive distances.

Talking about putting solar cells on top of the tunnels is a total joke if you are going to have 1km each side unoccupied.

Safe distance, LOL? By same merits, you would need to keep people away from usual high speed train at least a few km away as well 

No. A high speed train derailment is not an explosion. A Hyperloop crash can easily be an explosion. Totally different.

[wraper]

No. A high speed train derailment is not an explosion. A Hyperloop crash can easily be an explosion. Totally different.

Why, there is no fuel to explode compared to usual train. If you think about implosion because of vacuum, then it won't be that severe, it's  is only 1 bar of pressure difference. There would be bent tube worst case.

[amspire]

No. A high speed train derailment is not an explosion. A Hyperloop crash can easily be an explosion. Totally different.

Why, there is no fuel to explode compared to usual train. If you think about implosion because of vacuum, then it won't be that severe, it's  is only 1 bar of pressure difference.

You are kidding? You only need energy for an explosion.  All an explosive is is a way to quickly release a lot of energy. Another way is to have an object weighing tonnes travelling at 1000km/h come into destructive contact with a stationary tube.

Anyway, there is fuel. The carriages have to carry hours of compressed oxygen, and if you combine this with metals at their combustion temperature, absolutely massive amounts of energy can be released. Aluminium when it oxidises releases far more energy then any fuel.

[wraper]

A high speed train derailment is not an explosion.

I don't see any solid evidence that won't be the case for hyperloop.

Another way is to have an object weighing tonnes travelling at 1000km/h come into destructive contact with a stationary tube.

It won't be head collision, and it will just bounce away from a wall.

The carriages have to carry hours of compressed oxygen

More likely just compressed air. Also probably there won't be any as there won't be complete vacuum, just low pressure air. They could use pumps to compress air present in the tube.

Aluminium when it oxidises releases far more energy then any fuel.

You need aluminium powder for that to happen. Won't happen with solid piece of aluminium.

[usagi]

Another way is to have an object weighing tonnes travelling at 1000km/h come into destructive contact with a stationary tube.

It won't be head collision, and it will just bounce away from a wall.

objects travelling around 300m/s tend to behave quite differently than people are used to in normal everyday life, maximum of 26.8m/s.

one of my hobbies deals with objects normally travelling at 300m/s or more. objects don't bounce like you think they do. any contact at those velocities will be catastrophic.

regardless, hyperloop is a silly impractical pipe dream.

[HalFET]

Let's say they can travel at 1000km/h. The tubes have to be safe. There has to be a safe distance between tubes so a crash in the Up tube can't take out the Down tube. A safe separation may be 100 meters. That is not the worst part. It has to be safe for people in the proximity of the tunnels. A safe distance exclusion zone could be 400 meters? I do not know but we are talking  a possibility of a big high energy collision with shrapnel - it could be 1 km or more. So when they build the London to Edinburgh hyperloop that they talk about, are they going to build a corridor 2 km wide all the way through the heart of England? Even putting the tubes in trenches will not stop shrapnel flying for massive distances.

Talking about putting solar cells on top of the tunnels is a total joke if you are going to have 1km each side unoccupied.

Safe distance, LOL? By same merits, you would need to keep people away from usual high speed train at least a few km away as well 

No. A high speed train derailment is not an explosion. A Hyperloop crash can easily be an explosion. Totally different.

amspire, please do the math before you dream up explosion horror scenarios, lets go over the numbers:
A filled shipping container would weigh in at around 30 000 kg (more typical would be around 24 000 kg I'd expect), lets say it travels at the 1000 km/h as you seem to indicate. For a train travelling at 400 km/h to have the same kinetic energy it'd only need to weigh in at 187.5 ton. In comparison a TGV passenger train weighs in at about 380 ton, so it'd have even more kinetic energy than your hyper explosive container while travelling at 300 km/h. This still pales in comparison to the kinetic energy of an passenger or cargo jet at cruise speed, which is easily 10 times more still!

And the aluminium on fire one is a classic argument, honestly you'd have to do some pretty impressive stuff to set it off, not even incendiary weapons manage, nor does a pure oxygen atmosphere do the job easily, unless we're talking powdered aluminium. And believe me, given how many vehicles are built out of aluminium, the military has probably tried thousands of times to figure out ways to do it...

[nctnico]

Rubbish. uBeam and Solar roadways can both work in theory and also in practice, demonstrably so, that's a fact. They are just impractical.

In theory they are very inefficient way of using already existing technologies. Therefore I say they don't work in theory.

Nope, they can both be reasonably efficient enough in theory and kinda in practice even, just not under practical usage circumstances.
But it's semantics of course.
The idea of keeping a 1000km long several meter wide vacuum system working with a 1000km/h projectile in it is just madness.

The 1000km/h is a number not based on any safety testing. You can buy a car that can go at 440 km/h but that does not mean that it is safe to regularly travel anywhere at 440 km/h. The safe speed tends to come from experience, but in Australia, for example, they have settled for speeds varying between 70 and 110 km/h outside urban areas.

Let's say they can travel at 1000km/h. The tubes have to be safe. There has to be a safe distance between tubes so a crash in the Up tube can't take out the Down tube. A safe separation may be 100 meters. That is not the worst part. It has to be safe for people in the proximity of the tunnels. A safe distance exclusion zone could be 400 meters? I do not know but we are talking  a possibility of a big high energy collision with shrapnel - it could be 1 km or more. So when they build the London to Edinburgh hyperloop that they talk about, are they going to build a corridor 2 km wide all the way through the heart of England? Even putting the tubes in trenches will not stop shrapnel flying for massive distances.

Your reasoning sounds much like the scaremongering when steam trains, automobiles and airplanes where introduced. 
If you'd reason like that then every airport in the world should have a clearance of a 50km radius and the terminal buildings should be bunkers made from reinforced concrete!

[amspire]

None of the examples you are quoting are travelling very close to a thin stationary tube. In a high speed train was stopped dead in a few seconds, you would have a major explosion.

A fully loaded shipping container that was out of control could easily rip apart any sort of tube they are contemplating. I think you are kidding yourself if you are imagining that every possible accident will result in a nice controlled sliding along this fragile tube for a minute or more at this speed.

You want some numbers?

1000km/h is a bit under 300m/s. Lets call it 300 m/s. A shipping container can be 36 tonnes and a carriage capable of carrying it, propelling it and doing emergency stops would probably weigh something similar. So lets say a total of 50 tonnes.

The energy of the moving carriage is 1/2 x 50000 x 300 x 300 = 2GJ. If something broke causing a violent rotation of the load so that it ripped trough the tube, the motion would mostly stop fairly quickly. It would only take a second or so to reach the next support. If most of that 2GJ is dissipated in 10 seconds, that is 200MW of power released over that 10 seconds. That is enough to make things incredibly hot. How is that 2GJ/200MW disippated?

According to my rough calculations that might be wrong, this is enough energy to melt 3 tonnes of steel.

If a carriage hit another stationary carriage in front at 1000km/h, it would be the same explosive energy as half a tonne of TNT. How close is it safe to be next to a half tonne TNT explosion in a steel tube? It would be a pretty spectacular pipe bomb.

This is nothing like your experience of seeing a car crash.

[nctnico]

A Boeing 747 at 800km/h weighing 350 metric tonnes has a kinetic energy of over 17GJ.

[amspire]

Your reasoning sounds much like the scaremongering when steam trains, automobiles and airplanes where introduced. 
If you'd reason like that then every airport in the world should have a clearance of a 50km radius and the terminal buildings should be bunkers made from reinforced concrete!

There most definitely are serious safety concerns at an airport. The terminals are a fair way from the landing strips, the landing strips are kilometers long and there usually is a runoff area. All fittings along a landing strip are break-away. The safety has been treated as an engineering problem.

Hyperloop will have to do the same, but I haven't seen Hyperloop ever describe what would happen in the accident scenarios I am talking about. I think they are fair issues that have a right to be discussed. They are talking about one carriage every five minutes. That is one carriage every 50km. In a 1000km tube, there can be 20 carriages going at 1000km/h. If any safety system fails there will be an accident, and luckily with physics, we can estimate the energy of that accident.

Now if high speed trains ran at full speed in an exposed elevated steel tube, there would definitely also be serious safety questions. Where they do run, safety experts do analyse the whole journey and where a derailment would be a devastation disaster, they force the train to run at a safe speed.

Are any high speed train services run at just 5 minutes apart?

[HalFET]

Heh, 36 000 kg would actually be a partially filled 12 m container, and for 2 GJ half a ton of TNT wouldn't do the job unless you presume perfect detonation...

Anyway, amspire, a crashing aeroplane has more kinetic energy, is built out of materials which can be significantly more flammable, and yet the main cause of any fire or explosion is still the fuel and not the materials themselves, so for you to worry about aluminium and steel is rather interesting to say the least... Additionally aluminium is actually harder to set on fire than iron in a pure oxygen atmosphere. (Which I always found interesting.) Additionally your explosives vs. energy released calculation is off.

But lets go with your 50 000 kg assumption, have you considered how much of that energy goes into deforming/moving the materials involved? You're acting as if we're dealing with a theoretical immovable tunnel wall with an infinite yield strength and an object slamming into it in a perpendicular fashion. And even then the result is surprisingly less damaging than you'd expect. Remember that test footage of that F4 jet slamming into a concrete wall at 750 km/h? You're looking at something with about 300 MJ of kinetic energy slamming head-on into a concrete wall there, and that took place in less than 100 ms. And yes I know the wall moved during that test, but what they forgot to tell you was that it was placed on air bearings for that test and you could have probably pushed it forwards with a few folks...

[Someone]

Are any high speed train services run at just 5 minutes apart?

Both TGV and ICE services trunk at those sorts of headways in the fully automated sections, sometimes less.

[mtdoc]

Very good point. Even if the hyperloop is never realized as a large scale public transport project (as I suspect will be the case due to financial and political but not technical reasons)

I'm happy to categorically state that practical realities will kill it, even if the financial and political will are there.

You need to be more specific about what you mean by "practical realities". 

Sure, the vacuum part.
If "HyperLoop" becomes a reality then it will not involve the vacuum part as has been, dare I say it, hyped.
Make no mistake, the entire premise of the Hyperloop concept is based on the vacuum to lower to air resistance and lower the maglev power. It has no other "innovation".

First of all you have to define vacuum when it comes to the hyperloop. The amount of energy you can save depends linear on the density of the gas you are travelling through. So at 1/10 of the atmospheric pressure you save 10 times the energy. Some people may not call that a vacuum though.

Exactly.  Without specifying what is meant by vacuum, one can continue to move the goalposts on what is meant by successful technical implementation of the hyperloop concept.

The original Musk "whitepaper" was only meant to stimulate others to explore the idea of high speed transport in a tube with pressure lower than 1 atm. The various teams inspired to pursue this idea, all have different parts of the basic concept which they've focused on and attempted to optimize, etc.  If hyperloops are ever built, who knows what intraluminal pressure will turn out to be optimal to balance the other design considerations (cost, safety, etc)?.

Meanwhile Thunderfoot and his fanboys have had many of their half-baked technical criticism's debunked.  Some have backtracked from their initial claims of "technically impossible" to now saying that while technically possible, it is just impractical (but without being precise about what they mean by impractical). 

However in general IMHO you'd do better to take a more objective approach rather than being the umpteenth armchair nay-sayer. Going through the technical challenges and trying to find the economic angle without prejudice/judgement will result in a much more informative video and not deteriorate your credibility.

Good advice.

[EEVblog]

Some numbers on MagLev operating energy consumed:
http://large.stanford.edu/courses/2010/ph240/ilonidis2/

Maglev is also a very cheap and efficient mode of transportation. Maglev operating costs will be only 3 cents per passenger mile and 7 cents per ton mile, compared to 15 cents per passenger mile for airplanes and 30 cents per ton mile for intercity trucks. [8] Guideways can last for at least 50 years with a minimal maintenance because there is no mechanical contact and wear. [8] At 480 kilometers per hour, maglev consumes 0.4 megajoules per passenger mile compared to 4 megajoules per passenger mile of oil fuel for a 8.5-kilometers-per-liter (20 miles-per-gallon) auto that carries 1.8 people at 96 kilometers per hour. [8]. It is also interesting to compare the efficiency of maglev trains and conventional high-speed trains. Table 1 shows the energy consumption of the German high-speed maglev Transrapid and the German high-speed train ICE 3, both as functions of speed. Transrapid has better efficiency above 330 kilometers per hour but it is less efficient below 330 kilometers per hour.

This is without the evacuated tube, a.k.a Hyperloop.

Seems that most of the cost goes into the new infrastructure required. Hypoerloop will be what, maybe half an order more expensive than normal Maglev?

[nctnico]

Some numbers on MagLev operating energy consumed:
http://large.stanford.edu/courses/2010/ph240/ilonidis2/

Maglev is also a very cheap and efficient mode of transportation. Maglev operating costs will be only 3 cents per passenger mile and 7 cents per ton mile, compared to 15 cents per passenger mile for airplanes and 30 cents per ton mile for intercity trucks. [8] Guideways can last for at least 50 years with a minimal maintenance because there is no mechanical contact and wear. [8] At 480 kilometers per hour, maglev consumes 0.4 megajoules per passenger mile compared to 4 megajoules per passenger mile of oil fuel for a 8.5-kilometers-per-liter (20 miles-per-gallon) auto that carries 1.8 people at 96 kilometers per hour. [8]. It is also interesting to compare the efficiency of maglev trains and conventional high-speed trains. Table 1 shows the energy consumption of the German high-speed maglev Transrapid and the German high-speed train ICE 3, both as functions of speed. Transrapid has better efficiency above 330 kilometers per hour but it is less efficient below 330 kilometers per hour.

This is without the evacuated tube, a.k.a Hyperloop.

Seems that most of the cost goes into the new infrastructure required. Hypoerloop will be what, maybe half an order more expensive than normal Maglev?

But the Maglev is only marginally more efficient compared to a regular train according to that website. And the reason is simple: friction. And friction losses go up squared when the speed increases and that is exactly what the primary problem the hyperloop addresses. All in all the extra costs of the Maglev don't get you a lot advantages in energy preservation. And if you think only the Maglev can go fast then I hate to tell that the French have tested their TGV at speeds over 550km/h only existing tracks.

[EEVblog]

But the Maglev is only marginally more efficient compared to a regular train according to that website. And the reason is simple: friction. And friction losses go up squared when the speed increases and that is exactly what the primary problem the hyperloop addresses. All in all the extra costs of the Maglev don't get you a lot advantages in energy preservation. And if you think only the Maglev can go fast then I hate to tell that the French have tested their TGV at speeds over 550km/h only existing tracks.

I'm not saying MagLev is viable, in fact it seems not based on the lack of uptake.
The point is that that Hyperloop is just Maglev + Huge amount of extra cost and engineering complexity + less reliability + extra safety concerns, for what? Perhaps a small reduction in running cost, and some extra speed that would be lucky if it was double the existing solutions.
Yeah, Hyperloop sounds like a winner 

[wraper]

But the Maglev is only marginally more efficient compared to a regular train according to that website. And the reason is simple: friction. And friction losses go up squared when the speed increases and that is exactly what the primary problem the hyperloop addresses. All in all the extra costs of the Maglev don't get you a lot advantages in energy preservation. And if you think only the Maglev can go fast then I hate to tell that the French have tested their TGV at speeds over 550km/h only existing tracks.

I'm not saying MagLev is viable, in fact it seems not based on the lack of uptake.
The point is that that Hyperloop is just Maglev + Huge amount of extra cost and engineering complexity + less reliability + extra safety concerns, for what? Perhaps a small reduction in running cost, and some extra speed that would be lucky if it was double the existing solutions.
Yeah, Hyperloop sounds like a winner 

You only need a relatively small fraction of usual maglev power to move the thing within vacuum / low pressure air. Therefore maglev part of the system becomes much cheaper. If you can keep the tube part reasonably priced, then it's more viable than pushing the air by brute force of full blown maglev.

[james_s]

A Boeing 747 at 800km/h weighing 350 metric tonnes has a kinetic energy of over 17GJ.

Potentially carrying something like 57,000 US gallons of fuel too.

[David Hess]

I'm not saying MagLev is viable, in fact it seems not based on the lack of uptake.
The point is that that Hyperloop is just Maglev + Huge amount of extra cost and engineering complexity + less reliability + extra safety concerns, for what? Perhaps a small reduction in running cost, and some extra speed that would be lucky if it was double the existing solutions.
Yeah, Hyperloop sounds like a winner 

I wonder though if the extra construction cost to produce the specialized track or partial vacuum tube in this case is insignificant compared to the costs of securing a high speed rail track and purchasing the right of way.

How do other countries secure their high speed rail lines from vandalism?

[EEVblog]

You only need a relatively small fraction of usual maglev power to move the thing within vacuum / low pressure air. Therefore maglev part of the system becomes much cheaper. If you can keep the tube part reasonably priced, then it's more viable than pushing the air by brute force of full blown maglev.

Yeah, but regular Maglev has not taken off. Most of that seems to be the cost of new installation and lack of backward compatibility with existing rail networks. Operational cost seem fairly small in comparison.
Hyperloop may solve that small operational cost part and is guaranteed add a whole heap of extra cost, complexity, safety etc etc. It won't fly.

[IanMacdonald]

I wonder though if the extra construction cost to produce the specialized track or partial vacuum tube in this case is insignificant compared to the costs of securing a high speed rail track and purchasing the right of way.

The Edinburgh trams are good case study of the gotchas in that. Cost now approaching a cool billion, I believe. To serve just one route. 

[jonovid]

hyperloop may cost as much as the space shuttle program   
total cost of all the dome airlocks  and all high pressure expansion joints.
and the maintenance costs too.
be cheaper for Elon Musk to offer everybody free air travel

[David Hess]

I wonder though if the extra construction cost to produce the specialized track or partial vacuum tube in this case is insignificant compared to the costs of securing a high speed rail track and purchasing the right of way.

The Edinburgh trams are good case study of the gotchas in that. Cost now approaching a cool billion, I believe. To serve just one route. 

San Fransisco's BART faced this because they used a track gauge wider than standard.  But that was just dumb because there was no reason to do so when standard gauge would have worked just as well and maintained compatibility with industry infrastructure.  I suspect this was just an exercise in legislative rent seeking rationalized by the "more comfortable ride" excuse and it is one of my favorite examples of why public mass transit projects are a waste of taxpayer money at least in the US where legislative corruption is the rule rather than the exception.

[nctnico]

hyperloop may cost as much as the space shuttle program   

It wouldn't surprise me if more money got spend on crypto mining gear then the space shuttle program. You have to put things into perspective and modern day solutions get more expensive because the low hanging fruit when it comes to optimisations is long gone.