First successful Hyperloop test module hits 100mph in four seconds

Snake Oil

"Hyperloop may appear bonkers but Musk has a history of Getting Shit Done, and I'd be inclined to throw some R&D money in his direction, just in case."

Musk does not yet have a reputation for getting stuff done. He has a reputation for starting off a lot of stuff that might yet be really good, but it's still too early to tell if it's a commercial success. Both Tesla and SpaceX are losing a ton of cash at the moment (it's early days), and it's by no means clear yet that they can successfully turn a profit. Musk's Gigafactory for instance is extremely vulnerable to be rendered obsolete should someone else invent a battery more practicable than today's lithium-ions.

Hyperloop Passenger Throughput

Hyperloop is completely unrealistic. To be commercially successful public transportation needs high throughput. It doesn't matter how fast it is, if it can carry only a few hundred people an hour it's not going to pay for itself.

Last I heard Hyperloop would carry maybe 20 people per pod. With pods travelling individually (they can't have a set of them joined together like a train), you'd be leaving a gap of at least, say, 2 minutes between pods for safety, so that's 600 people an hour.

That's truly pitiful. A Shinkansen can carry about 1500 people, and there's one every 5 minutes between Tokyo and Osaka. That's 18,000 people an hour, 30 times more people. And they can run them more regularly than that if they have to.

Is Even that Rate Achievable?

To be honest I doubt that they could ever get Hyperloop working that regularly either. To launch it you have to get people into a pod (1 minute), strap them in (5 minutes), put the pod in an airlock (30 seconds?), pump down the airlock (5 minutes?). So that's a launch time per pod of about 12 minutes, meaning you'd need at least 6 launch stations to keep sending them once every 2 minutes. And then with the usual "hang on a mo I've got to kiss the girlfriend goodbye" type delays that schedule could be easily screwed.

If they had a bigger pod they'd simply increase the loading time (more people, more air, more room for screw ups).

And to make that schedule work at all you'd need airline style check in to make sure people are in the right place at the right time, or passengers would have to be queued up to ensure there's a ready supply of passengers to fill pods. Both are bad news for the passenger experience. What's the point of queuing for an hour in the hope of getting a pod, or checking in 1 hour beforehand for a 30 minute journey?

Trains don't have this problem. A train pulls into the station, the doors are open for 1 minute, and you're away. 1500 people have got on and are on their way. It doesn't matter that people haven't sat down yet or put their luggage away because trains don't accelerate at Hyperloop's unnecessarily high rate. If demand increases you simply run longer trains.

Emergency Braking

And getting back to that 2 minute gap; to be able to go from near Mach 1 to stationary in 2 minutes requires a deceleration of at least 0.25G, though probably more given the signalling block sizes, etc.

That's actually quite a lot; along the entire length of the tube a pod would have to be able to generate this much braking force for it to be deemed 'safe' to run a pod once every 2 minutes. Given that a pod has no wheels, or anything else like it, the only tractive force available is electromagnetic.

But the whole point of Hyperloop is that the pods in the cruise phase have very little drive (which makes it cheap), so it would also have very little braking power.

So where does that 0.25G braking come from? Does the tube also have to act as a braking surface for friction pads? Does that wear out? Can it be used again afterwards?

There's so many technical barriers to safe and regular operation I can't see it happening. Increasing the inter-pod time makes the throughput even worse. Installing the necessary braking system makes the tube much, much more expensive.

Just Build the Train

In comparison to Hyperloop, high speed rail between LA and SF works commercially. It's approx 350 miles, which is 1 hour 45 minutes in a standard bullet train without stops. In that time you'd also have WiFi, 4G, a snacks trolley, etc. so the "extra" travel time isn't a complete waste. It's a good proposition for passengers.

Putting any government money into the snake-oilesque hyperloop would be a waste and a travesty. The companies involved are putting forward the "hey isn't it cool" without doing the simple analyses that say whether it's commercially realistic.

I notice that Musk himself isn't actually devoting much of his own money to the project, in effect licensing out the concept to others to do all the hard work. If that isn't a worrying sign about its lack of commercial viability I don't know what is.

@TheOtherHobbes,

"Apparently HS2 needs at least £20bn to run a fairly conventional choo choo train all the way from London to Birmingham - which is about a quarter of the distance of LA to SF."

Land isn't cheap in the UK, and the ground is not very suitable (too soft) for building a high speed railway so we may have to lay down concrete foundations for big chunks of it.

But it's still probably worth it. The land in Japan isn't very good either (mountains, mud planes, requiring a lot of tunnels and a lot of elevated concrete track), but it didn't stop them and the resulting benefit to Japan is incalculable.

One big difference in Japan; the rest of their transport network is up to the job of feeding passengers to the Shinkansen lines, airports, etc. The density of metropolitan railways in Japan is unbelievable, meaning hardly anyone needs to drive anywhere at all (at least not in the major towns). Even their buses are really good.

In contrast in the UK the buses are poor and it's only really London that has an widespread metropolitan railway network. The result is a lot of us will have to drive to the high speed train stations. No one wants to spend and hour or two on buses to get a 45 minute train to London. If we have to jump in our car to make the journey time sensible, why not just drive the whole way?

So I think that whilst HS2 is a good idea, there's a hell of a lot of work to do beyond that.

California's $80B HSR "Plan"

A few years back Californians got to vote on the early version of High Speed Rail funding. We were asked to approve $10B in bonds to fund a $30B rail project (SF-LA and beyond to SD and SAC), with the rest of the funding being magic money that would appear from the sky, and $55/ticket SF-LA, cheaper than Southwest Air on sale. Immediately after it was approved they said "Oh, ooops, we'll have to pay interest on bonds! Ok, it's $40B." After a while it was "$70-80B, $110/ticket", and recently it's "Oh, apparently ridership will depend on ticket price, who could have guessed that? So maybe we'll need to subsidize it more to get ridership up!"

Re: When Things Go Wrong.

You get traffic jam - and you need a big spoon

Re: Los Angeles to San Francisco route comes in at $6bn

@jphn37,

"There may be problems. That's what the startup are for: to iron out the problems with the tech. But what's with the massive negativity?"

The negativity comes from the fact that even a cursory examination of the engineering barriers to achieving an economically viable and beneficial high throughput passenger service leads one to realise it's a dead-duck of an idea.

Sure, something could be built, but as currently envisaged it won't carry many passengers, so it won't deliver a useful service, and therefore it won't pay. Imagine:

1: "Lets go to LA!"

2: "Sure! Plane, car, train or 'loop?"

1: "Not the 'loop, the queues are awful and you can never get on it"

2: "Well I don't wanna drive, and we haven't got air tickets booked"

1: "Let take the train then, it's only a couple of hours".

or

1: "Lets go to LA!"

2: "Sure! Plane, car, train or 'loop?"

1: "Not the 'loop, I know it's fast and there's no queues these days, but it's soooo expensive"

2: "Well I don't wanna drive, and we haven't got air tickets booked"

1: "Let take the train then, its only a couple of hours".

Result: no one ever goes by 'loop.

Re: Los Angeles to San Francisco route comes in at $6bn

The problem is not if they research that technology and try to get past usability issues.

The problem is if everybody just wait for it to become feasible, while the rest of the transportation system is hopelessly outdated and slow. High-speed trains are an existing working solution, using a proven technology. Why wait for a more futuristic one still in its infancy?

There could be some resistance form airline companies that may not like shorter routes flights becoming noncompetitive against the trains, as it happened in many countries that deployed high-speed trains, and may want to delay the inevitable.

But the US had many of the most advanced trains until the 1940s - then modernization stopped, and they started to lag behind not only Japan and Europe, but China as well. Rebuilding a railroad infrastructure will have more benefits than bailing out banks and insurances went bankrupt due to their own greed...

Re: Los Angeles to San Francisco route comes in at $6bn

"What happens when it fails, and passengers are trapped in a vacuum with the next car hurtling towards them at Mach 1? How long does it take to plasma cut them out?"

Don't worry, sound can't travel through a vacuum, so at Mach 1, the next train will never arrive....

Re: Los Angeles to San Francisco route comes in at $6bn

Feeding in air will generate problems on its own. It can create turbulence inside the tube, and apply the wrong forces on the pod - and the pod shape should be designed to take that into account. At those speeds, friction will also generate heat that would need to be dissipated properly. Then the pod should be able to move itself to an emergency area and allow people leave it.

Another solutions could be to have emergency thrusters to slow down, but most of them will "contaminate" the environment and probably block the whole line for a while.

Re: Purpose of the test

The purpose of the test is to encourage investment from people like those on this forum who are excited enough about "the future" that they're willing to ignore the basic numbers that already show it incapable of returning their investment.

This isn't the first time nor the last that this sort of thing will happen.

But what problem are these people exactly trying to solve? If you want to ship small numbers of people rapidly from A to B for obscene prices, what's wrong with business jets?

At least in a business jet, when turbulence hits, you can chuck up in your sick bag and take a trip to the loo to freshen up.

In "the tube", as soon as someone barfs, you're likely to end up sharing their chunks for 30 minutes. And with those numbers of G force and the 'rollercoaster' effect, I wouldn't be surprised if there's a "chucker" on every trip.

Re: Los Angeles to San Francisco route comes in at $6bn

"As opposed to a plane which will just fall out of the sky."

Only if parts fall off. If a plane runs out of fuel but is still intact, it's designed to start gliding, which at least gives time to find someplace to land the bird.

Re: Nonsense

Clever but he was provably wrong even by the science of his time. The fact that he was important did not mean that he understood the physics even of his today. Godard was told that Rockets cannot work in a vacuum by I believe the New York Times. They too were probably wrong by the science of their time and of centuries before. Just because important people don't understand physics and make boneheaded pronouncements about impossibilities does not mean that every time somebody mentions physics and call something impossible or impractical they are wrong.

But in many ways that is beside the point. There is nothing about the hyperloop that is physically impossible. But it is a vacuum and that has engineering and logistical and safety considerations. It is accelerating *very quickly*. and we understand very well the physical ramifications of that. It also falls prey to amdahl's law, which in this case means speeding up a portion of a trip a lot just not necessarily improve the overall trip time all that much.

Re: Nonsense

So how exactly do you do a magnetohydrodynamic drive "properly", then? Turn the air in front into a plasma and eject it with a magnetic field (Lorentz, not Laplace, I assume)? Sounds totally impractical to me.

Re: Nonsense

The Hyperloop isn't evacuated. It runs at low pressure.

Re: Holy shit.

Pumping large amounts of air down a tube at high speed is incredibly inefficient. You'd lose huge amounts in friction and turbulent flow. That's why this system uses a near vacuum. You get that small pressure distance over a large area but suffer relatively little loss in friction and turbulent flow.

In addition, if imagine the consequences of trying to stop all that air flowing in an emergency. There would be a huge amount of kinetic energy in all that moving mass of air.

Re: Freight is toughter than you think

Actually, a shipping container sized pod makes sense. Slot a container, into it and off you go. That container could be full of freight, or fitted with seats. Then the passenger loading (and all the associated people problems) is decoupled from the train.

It's unconvincing. You still have to get the containers ready and load them. You'd simply be pushing the problem back a bit.

As for freight, it's a joke. To move a container that way you'd be putting it on a truck, driving it to the loop station in the centre of SF and then you'd be waiting for a free slot. Either you pay a lot of money to get an early slot, or you wait a long time.

One wonders just how far down the road to LA the truck would now otherwise be, or how much cheaper air freight would have been.

Re: Freight is toughter than you think

I'm struggling to understand just what sort of bulk shipping requires speeds like this and would be cost effective. The sort of goods transport that uses very fast air distribution (and this is primarily and alternative to air transport) doesn't use standard shipping containers.

Something like hyperloop would surely only be used for relatively high value, time-critical cargo as would normally travel by air. If the economics were right, then some goods currently carried by rail and/or road might get moved across, but surely not the sort of bulk stuff that foes by shipping container. Those will surely still be transferred by appropriate bulk systems, like water, rail and some trucks.

The human body wasn't designed.

@Known Hero

The fact that 50% of all drivers have not died in a fiery crash tends to somewhat invalidate your argument.

Re: So many luddites...

and lot's of people don't think electric cars will work either, but we are well on our way to achieving it.

Re: So many luddites...

"Because we don't believe in an overhyped technology with a lot of obvious unresolved engineering and logistical issues (that bazza outlined better than I could earlier in this thread) we're Luddites?"

Engineering issues like hot landing a first stage booster stage on a floating barge having delivered the second stage to a geosynchronous transfer orbit?

Or like building an electric car which will do more miles to the charge than many of the petrol cars I've ever driven - and can have their battery swapped in less time than it takes to fill a tank?

Good thing we don't have the same person trying to change too many forms of transport. I mean a consistent approach can't possibly work on a third transport mode can it?

Is sanity doing the same thing that has worked before and expecting it work again?

Re: Technical Question

I think I get it. The speed of sound IS affected by density (which is why it travels faster in liquid and faster still through a solid), but in a gas this is perfectly counterbalanced by an inverse correlation regarding gas pressure (meaning it slows as the pressure rises). Keeping temperature constant, raising density also raises pressure and the reverse, and the two factors cancel each other out.

Now, under normal circumstances, evacuating a chamber will pull heat out of it, making it colder, so taking temperature into consideration, pulling a partial vacuum would lower the speed of sound, though not by a tremendous amount given we normally hover near 300K anyway and the partial vacuum isn't likely to drop that by more than 10-15% under practical conditions.

Re: Concorde

"This also allowed it to travel rather a lot faster than a Hyperloop, take off and land all over the world"

It was only faster than Hyperloop where it was allowed to fly supersonic, ie over oceans. The sonic boom carpet for Concorde was around 20 miles wide and meant that flight routes were rather limited sadly. It's why the Singapore route was discontinued.

Re: Concorde

So Concorde looked better, was faster, more flexible, more practical and pleasant... and we built it about 50 years ago. A more elegant solution from a more civilised age.

Have you seen this project?

It's something of a long-shot, but would be marvelous if it were to come off...

Vic.

And regarding intermodal transport, trains have optimized themselves considerably over the last two decades. One of the big changes was the well car which let trains carry two standard transport containers per car (and here's the beauty: with a powerful enough locomotive, you can pull hundreds of these cars; I routinely see freight trains pulling nearly 200 cars at a time, though in my neck of the woods they're mostly ore cars). Combined with improved rail-line communications to track trains and cars and optimization at transfer points, they can easily beat trucks in land transport efficiency under many different scenarios.

Re: Objections, objections...

"If you are against X, then by definition you are wrong because new things that were hard turned out to be easy"

Well no - they still proved to be hard, and in many cases still are hard even though they have solutions that have been used for decades.

Spaceflight is a good example.

Perhaps all the issues raised by people on this thread are all completely unsolvable; perhaps some are but not in a satisfactory way; perhaps some can be solved, or solved in a better way, by changes to other parts of society and environment.

Public & private investment money gets wasted on far worse and worthless things than a high-speed transit system that can be wholly powered by non-fossil fuels, and can potentially reduce car and air transport use over medium-long distances but hey, I know from being here a long time that EngineerReg seems to be comprised of people who really don't like new ideas if they personally can't see a solution to the issues at hand.

Re: Gravity...

"You'll need some tubes that don't melt or bend, and a good aircon system, but that's just a small matter of engineering."

You left out the casino, bar and a buffet. And, the toilets.

Re: The key question

Domestic electricity is about 8p /kWh. Presumably if you're buying it in these quantities you can get a better deal but just to set an upper bound it would cost you about £750/hour for 9.3 MW, ie running the train flat out over a very long distance without stopping at intermediate stations so that the acceleration costs aren't significant relative to fighting the air.

That means this $6Bn dollars would be enough to run a TGV for 5 million hours, 570 years.

Of course you couldn't really run a TGV for 570 years with that money but that's precisely the point. The cost of overcoming drag is not the main factor, or even a significant factor.