Tuesday 13 August 2013

High Speed 2? I want a Hyperloop.


Hello! Following up from the critically acclaimed (by my Nan) blog A Welshman in America and inspired by a few friends who are making much better use of social media than me, I have decided to start filling up the internet with ramblings again. This blog will try focus on science and technology, with inevitable diversions as I start my astronomy PhD in September. I’ll talk a bit more about some of the wide themes I want to cover, but it will basically be “what do I find interesting today?”

And today has seen the release of something very interesting indeed: The Hyperloop.

Described by inventor Elon Musk as “a fifth form of transportation” (The other four being road, rail, water and air travel) this design promises journeys between cites at almost the speed of sound. It will cost less than driving by car and have almost no environmental impact.

Best of all, the whole thing has been given away for free. The details are all on the websites of SpaceX and Tesla, two of Musk’s current ventures, so you can just download them, have a read, then go and try and build one yourself. (And check out the rest of those websites while you’re at it, I’ll almost certainly becoming back to both those companies at some point.)

For those of you who don’t want to read the paper, a journey on the hyperloop is roughly as follows. You and 23 other passengers would climb into a roughly 1.5m diameter pod or capsule, sitting in reclined seats with on board entertainment screens in front of you. Your luggage, roughly as much as you can take on a plane, is stowed in a separate compartment behind you.

Once everyone is in, the Back to the Future style gull-wing doors close and the capsule moves through a large airlock. The airlock quickly pumps out most of the air around the capsule, bringing the atmospheric pressure down to  100Pa, or about 1/6th that of Mars. (Musk uses the comparison with the Martian atmosphere, rather than that of Earth, throughout the paper: His ambitions regarding the fourth planet from the Sun are well known).

From the airlock the capsule moves into the main element of the system: A tube connecting you and your destination, held 30m above the ground on a series of pylons and covered in solar panels. The hyperloop generates much more power than it needs, so your transport is also a power station.

The capsule then passes over a series of impellers, which use electromagnets to accelerate the capsule up to speed. In an identical tube next to you those same impellers are being used to slow down a capsule coming the other way. The remaining air in the tube is sucked into the front of the capsule and forced out of the sides, allowing the capsule to float in a similar way to a hovercraft. With almost no friction, the capsule can then be accelerated to up to 1120 kilometres per hour, or 760 miles per hour.

The case study route, a 350 mile route joining Los Angeles with San Francisco, would take roughly 35 minutes.    

That’s over twice as fast as a plane making the same journey. Nearly 5 times faster than high speed rail. And ten times faster than a car.

(All of these comparisons are for actual day to day journey times, not a “if a train, a plane, a car and a hyperloop had a race, which would get there first?” sort of thing. Which incidentally would make a very good episode of Top Gear.)

Although it sounds very science-fictiony, there’s actually no new technology involved. All of the basic elements- vacuum pumps, air cushions, and magnetic impellers- are already around. And anyway, criticising something for being “too futuristic” is a bit silly now that one in seven of us are carrying supercomputers around in our pockets. 

And as the BBC says, no one is betting against it. Elon Musk has a track record of taking things that sound years away and dragging them into the present. He made his fortune with PayPal, then revolutionised spaceflight with rocket company SpaceX. Another company, Tesla Motors, is doing rather well in the electric car business.

With Musk’s track record, the use of proven technology and the fact that anyone can have a go, I wouldn’t be surprised if at least someone, somewhere has a go at building one. In fact, I suggest we build one here in Britain.



Musk says that his interest in the hyperloop was sparked when he saw the plans for the high speed rail link between San Francisco and Los Angeles. This plan has the dubious honour of being both one of the slowest and, at estimated costs of over $60 billion, one of the most expensive high speed rail links in the world. According to Musk and his engineers at SpaceX and Tesla, the hyperloop would cost a tenth of that price and have a journey time five times as fast.

This raises the obvious question about whether a hyperloop could replace Britain’s very own uninspiring high speed rail project, HS2. Although it’s not quite the same situation as California, as there isn’t a convenient long, straight road to put the thing next too, I’m sure that I can make some rough comparisons. (One of the advantages of a hyperloop is that you can site it alongside existing infrastructure instead of having to build railways. As it’s up on towers it’s pretty much just like putting another set of electricity pylons in.)

First let’s have a look at the competition. HS2 will be 192km long (the first phase to Birmingham, as the second phase is so far in the future it’s probably not worth talking about), and will take roughly 50 minutes to get from London to Birmingham, a saving of about 30 minutes on current times (wow). The projected costs are roughly £16 billion.

Now let’s see if a hyperloop can do better. This will be a rough estimate as no one is paying me to do it properly (Hi, people who pay people to do it properly…). Let’s put our hyperloop along the side of the M40, which is vaguely straight from London to Birmingham. That makes it about 150km, rounding up a bit for any extra length needed to go round corners less quickly than the motorway. The West Coast Main Line would be another option, but it’s not as straight so I’ll stick with the motorway. Perhaps the solar panels on the hyperloop could be used to run charging stations for electric cars along the way.

As most of the cost of the hyperloop is in the tube, I can estimate the cost by comparing the length of this tube to the Californian one. This makes it about a 3rd of the length of the Californian one, so it’ll be roughly a third of the cost (all of these are overestimates to account for the fact it might be more expensive per mile due to the difference in location.) The more expensive version of the hyperloop (carrying cars as well as passengers), costs $7.5 billion. A third of that is $2.5billion, or roughly £1.7 billion rounding up. Let’s call it £2 billion, or an eighth the cost of HS2. So far so good.

Journey time won’t be quite as straightforward, as a greater portion of the distance will be spent speeding up and slowing down at each end. So let’s say we only get about 2/3rds of the journey time of the California system rather than the third our distance suggests. The California route takes 35 minutes, so I’ll say roughly 20 minutes. That’s 2.5 times faster than HS2 and saves over an hour on current journey times.

That’s much cheaper, much faster, better for the environment, generating free electricity, not digging up farmland, and not making a new eyesore. In fact as it’s next to the motorway it would be making a current eyesore better. Better then in every way than HS2.

I think we should build a hyperloop. Not just because my simple calculations show it’s better (someone please do a more in-depth analysis), but also because what it represents.

It’s a twenty-first century form of transport, something that makes use of all the developments over the past few decades to build the best possible way of getting people around, not relying on technology that’s been around for fifty years. The plans are open source so anyone can have a go designing one, and all the technology already exists. Giving the county a project like this would help to inspire a new generation of scientist and engineers, who would be able to see the future not hidden away in a phone in a pocket, but stretched across the landscape. Why shouldn’t we build one?

Neil Degrasse Tyson has said that “Doing what’s never been done before is intellectually seductive, whether or not we deem it practical”. The hyper loop certainly looks practical and it’s definitely never been done before. Let’s have some intellectual seduction.


Of course the most important question has yet to be answered: Could a hyperloop do a loop?

Hope you've enjoyed the first post of my new blog. Next time I'll talk a bit more about what I want to talk about (that makes sense). The blog's name was inspired by this xkcd post.

New posts will be posted on my shiny new Twitter page.

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