Hyperloop- future of rail or wibbling insanity?

[jopsuk]

The founder of Tesla Motors Elon musk has managed to excite all the tech website this morning with a post about a proposed maglev/atmospheric railway system he's dubbed "HyperLoop".

The details are in this blog post- there's a large PDF linked there

When the California “high speed” rail was approved, I was quite disappointed, as I know many others were too. How could it be that the home of Silicon Valley and JPL – doing incredible things like indexing all the world’s knowledge and putting rovers on Mars – would build a bullet train that is both one of the most expensive per mile and one of the slowest in the world? Note, I am hedging my statement slightly by saying “one of”. The head of the California high speed rail project called me to complain that it wasn’t the very slowest bullet train nor the very most expensive per mile.

The underlying motive for a statewide mass transit system is a good one. It would be great to have an alternative to flying or driving, but obviously only if it is actually better than flying or driving. The train in question would be both slower, more expensive to operate (if unsubsidized) and less safe by two orders of magnitude than flying, so why would anyone use it?

To me, it doesn't actually look that revolutionary- there's been many proposals for "trains" in vacuum tubes in the past. Usually maglev. His sytem, in common with others, seems to have the usual failure to even consider how points would work.

He's also suggesting linear acceleration of 1g- that is, 9.8ms^2. That's a 0-60 time of 2.7s.

He's suggesting max lateral acceleration of 0.5g- what's the maximum allowed on conventional trains?

He gives no idea as to what braking rate would be required

 

[gordonthemoron]

and also units conveying cars at 800 mph, sounds alarming

 

[Eagle]

Regarding braking, with a forward deceleration of 10 m/s² (1 g) it would take a whole 36 seconds to slow down from 800 mph to zero.

Braking at 50 m/s² (5 g), which would be very uncomfortable for more than a brief instant, would still take over seven seconds. That's enough to render most passengers unconscious.

 

[HSTEd]

The figures he gives for HSR energy consumption are out by an order of magnitude.
He assumes that HSR must run on the surface while he can use endless tunnels.
And numerous other problems I didn't have the patience to find.

In short, its all nonsense and shot through with horrific lies.

 

[gordonthemoron]

sounds like something out of Thunderbirds

 

[Ironside]

I like the concept of vacuum maglev, but the lack of clear data and explanation of how it would be done means It's pretty much just a few futuristic drawings intended to offer an alternative to high speed rail like RP2 to HS2.

 

[HowardGWR]

Makes Brunel's 'atmospheric caper' look sensible.

 

[brianthegiant]

The media are all over it but I haven't noticed a single outlet get an independent comment from an engineer.

I can't imagine the people at Tesla are really this dumb, I suspect it's really intended to provoke a debate about the spec & costs for new US high speed lines. eg http://en.wikipedia.org/wiki/California_Corridor

 

[starrymarkb]

Musk are known to be rather litigious aswell with people who disagree with him, and he wants to build the tubes above I-5, is the Interstate curve radius suitable for 800mph?

 

[samuelmorris]

2m/s^2 in either direction has got to be about the limit. 0-60 in 6 seconds is only 4.5m/s^2 and for anyone other than the fit & able-bodied, that's pretty unpleasant to do on a regular basis, even in a comfortable seat. 10 has got to be bull.

 

[BestWestern]

Without meandering too far off topic, is there a reason why 'traditional' maglev tech has never found widespread use? It doesn't interest me in the slightest from an anorak point of view but I always understood it to be perfectly do-able, and presumably beneficial over normal rails for long distances at high speeds?

 

[gordonthemoron]

IIRC it wasn't built in Germany because it was viewed as too expensive and isolated (i.e. couldn't be incorporated to existing network)

 

[Class172]

This whole proposal of transportation in tubes just makes me think of Futurama where people travel in small tubes to get places.

 

[Eagle]

Without meandering too far off topic, is there a reason why 'traditional' maglev tech has never found widespread use? It doesn't interest me in the slightest from an anorak point of view but I always understood it to be perfectly do-able, and presumably beneficial over normal rails for long distances at high speeds?

Zero compatibility with conventional rail, mainly. Also junctions and the like are tricky to build and maintain (a maglev is strictly speaking a kind of monorail).

 

[matthewmacleod]

It's a little bit frustrating that so many people have not taken the time to understand what is being described.

A couple of important points:

• This isn't maglev. It's linear motor drive, but with air-cushioning - essentially a massive air hockey table.
• This isn't a vacuum tube. It's reduced-pressure - the air in the tube is essential for providing the support for the capsule within the tube.

I guess it's important to avoid comparing directly with rail transport. This is more of a proposal for a transport system which sits in between rail and air - higher-speed than rail to make longer distance travel more accessible, but more energy efficient and less time consuming than air transport. The proposal to essentially self-power with solar energy is also exciting. Given that the current proposed cost for the Californian HSR corridor is around $70bn, which is totally preposterous, it's not hard to see why there's some excitement around this.

It's going to be important to avoid hero-worship of Musk, but it's worth bearing in mind that SpaceX has successfully commercialised space travel - it does seem that there are few people or companies more suited to developing next-generation transportation methods.

 

[Tim R-T-C]

The main problem with this scheme aside from technical factors is the fact that it is presumably going to only work as point to point system - so maybe it will be useful for travel from city centres but will not offer the range of stops that makes the railroad competitive.

 

[HSTEd]

It's going to be important to avoid hero-worship of Musk, but it's worth bearing in mind that SpaceX has successfully commercialised space travel - it does seem that there are few people or companies more suited to developing next-generation transportation methods.

No it hasn't.

It has just reached launch costs that are not hilariously worse than those using proven Soviet designed launchers and their immediate derivatives.
It is the first real new-build launch vehicle in the west since the 70s other than the shuttle (which was a debacle for its own reasons) and it shows.

Anyone could have done it were the Americans not constantly in hock to the large aerospace corporations.
There is only one real 'innovation' in the Falcon series and that is something they lifted from the Soviets - the launcher hold down.

There is a reason that the Commercial Space launch business that the American industry used to have has been eaten up by Ariane and the Eastern Bloc with Proton and Zenit.

 

[matthewmacleod]

Anyone could have done it were the Americans not constantly in hock to the large aerospace corporations.

They didn't, though.

Fact is, at the end of the day, SpaceX is launching space missions in exchange for money, and is the first private enterprise to do so. That's pretty impressive, regardless of the fact that it should never have been required in the first place.

 

[HSTEd]

They didn't, though.

Fact is, at the end of the day, SpaceX is launching space missions in exchange for money, and is the first private enterprise to do so. That's pretty impressive, regardless of the fact that it should never have been required in the first place.

All it takes is someone willing to throw several hundred million dollars of start up capital at it.

It is hardly impressive beyond that Elon Musk was willing to throw that much money in, not that it would have ruined him anyway.

EDIT:

ArianeSpace is a commercial launch operator, although it is, via a very long chain of parent companies, partially state owned.

 

[Searle]

The media are all over it but I haven't noticed a single outlet get an independent comment from an engineer.

I can't imagine the people at Tesla are really this dumb, I suspect it's really intended to provoke a debate about the spec & costs for new US high speed lines. eg http://en.wikipedia.org/wiki/California_Corridor

Channel 4 News had an engineer on who said it was a cool idea but not feasible at all. Meanwhile there was a woman from America on saying it was the best thing since sliced bread and there was nothing at all wrong with it

 

[rdeez]

I'm no professional engineer, but he's included a document going into a fair amount of detail and seems to have done the physics (whether he's correct or not, I'm sure we'll get some independent opinion shortly).

It may seem wacky at first glance but really, how old is rail technology? The basic wheels-on-rails part, at least. Fundamentally, it's barely changed from its inception, and yet most new projects seem to push ahead with traditional rail - usually for compatibility and / or cost reasons. It's a shame nobody seems to want to push ahead with a next-gen technology, or even deploy more advanced existing ones, like maglev, on a wider scale. Yes, there are issues to be resolved, but with the right investment and development they could be resolved. Yes you end up with a system not compatible with what's already in place but over time they could begin to replace the older networks.

Something like this could be a viable replacement for domestic air travel between large cities, a consideration that shouldn't be quickly dismissed, considering that air travel consumes vast amounts of fuel and we all know that oil isn't going to last forever.

 

[DynamicSpirit]

Given that the current proposed cost for the Californian HSR corridor is around $70bn, which is totally preposterous, it's not hard to see why there's some excitement around this.

Why is that preposterous? $70bn would be abut 45£bn which is slightly less than current estimates for HS2. But the Californian HSR will be more than twice as long.

 

[jopsuk]

I'm no professional engineer, but he's included a document going into a fair amount of detail

It has a lot of detail on parts such as the electrics. On other crucial stuff, it has little but wooly handwaving.

 

[YorkshireBear]

The acceleration and deceleration rates look rather optimistic at best. I just think running at 800mph through a tunnel in an earthquake zone is not the best idea....

 

[Crundles]

The premise is not a million miles away from the Tracked Hovercraft/Aerotrain projects of the 60s/70s. The UK's RTV-31 prototype used air cushion technology with linear induction motors to propel vehicles along elevated concrete tracks:

In fact, there was similar proposal in the same part of the world as the "Hyperloop" by Rohr Industries. The idea was to serve airports and even a link between Las Vegas and Los Angleles:

The French also developed their own version - the Aérotrain - in parallel but it used more conventional aeroplane engines.

Of course, these vehicles were not enclosed in a low pressure tunnel. I do agree that some the more eye catching figures seem a little optimistic.

 

[eps200]

A few engineers have chimed in on reddit it's not insane but not comercial either it's at the, we should look into it with R&D money stage.

Musk has done here what he does best, take an existing idea break it down to it's fundamentals and make a cheaper, simpler, better one.

Tubes spec is well within that of existing oil pipelines. Points are side stepped it's point to point you turn at stations.
Power is also sorted, he has a huge stake in a solar panel company lay pannels along the top of the track. Someone on reddit ran the numbers it would actually have too much power and have to put some back in the grid. Another poster spotted that the electrics would be just perfect to run chargers for his electric cars off of which is just so convenient.
Levitation doesn't use maglev it's proposed to use air bearings which i quite fancy but already commercial tech, this thing would need much beefier ones though.
Acceleration is him getting carried away it's perfectly viable from a technical point of view not so much form a legal one. Not quite as insane as it sounds though as the pod can bank agaisnt the tube. Breaking is done via the linear motors used to boost the pods along the way energy is recovered each time one breaks.
Lowering the pressure in the tubes is also quite sensible, it takes a lot less energy to maintain a low air pressure than to fight drag constantly the air is circulating in the loop at ~300mph even as the pods exit and enter this conserves a lot of energy. We wont see much in the way of speed improvements for traditional rail at this stage it's not going to double again the physics just says no.
On the other hand he clearly knows nothing about civils not a show stopper for the proposal but it means his cost estimate is at least an order of magnitude out.

This sort of thing isn't really an alternative to high speed rail it's to fit in between HSR and air travel ideally it would kill off short haul flights. though taking the end to end passengers off the rail network would have benefis worth tallying.

 

[tony_mac]

Tubes spec is well within that of existing oil pipelines. Points are side stepped it's point to point you turn at stations.

I think the document suggests that the tube 'splits' to serve different destinations, but doesn't say how it might be done.

However, it's not just the cost estimate, but the capacity - it is barely 1/10th of the projections for the rail link - and that is assuming it is at full capacity for 24 hours a day. (Although there is a note that the frequency could be quadrupled at peak periods, but that's not included in any of the 'costings').

The idea of spending 40 minutes in a 1-metre high capsule doesn't really appeal to me. Could you imagine spending 5 hours in there because the brakes locked?

 

[eps200]

Capacity i got 28*120=3360 seats per hour, HSR is more like 1,000* what ever TPH your line can handle.
It's hard to work out how well each uses the seats. HSR is taking a thousand every few minuets hyperloop is a continuous stream of people.
Capacity is an issue but then again it's not a train he's gunning for short haul flights it only competes with HSR at the edges.

To answer the OP no not the future of rail travel but maybe the future of intercity journeys.

 

[tony_mac]

Capacity i got 28*120=3360 seats per hour, HSR is more like 1,000* what ever TPH your line can handle.

That's at the faster frequency of every 30 seconds which is only mentioned in passing - everything else seems to assume that there is one every 2 minutes.

It looks like I was wrong about the estimated passenger numbers for HSR - it seems that I was looking at the total passenger numbers and not the rail passenger numbers. So the higher frequency would be comparable, although again assuming a full load for 24 hours a day.

However, one of the problems is actually building a working prototype is going to be very expensive; it could be a lot of money to spend to find that it just can't be made to work reliably for all sorts of possible reasons.

 

[Tiny Tim]

Neither the future or wibbling insanity! I won't predict what the future holds for high speed transport, but I bet it isn't going to rely forever on two steel rails.