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Tuesday, August 20, 2013

Hyperloop - Big Engineering 54 - Far Faster & Cheaper Than HS2

Latest Article up on ThinkScotland. Please put comments there. I'm putting this up as a Big Engineering item though I certainly didn't invent it (I suppose I can claim to have "ivented" the fairly obvious idea of applying it Glasgow to Edinburgh. I did previously do a BE on vacuum trains

    Elon Musk is the boss of SpaceX, creator of the Tesla car and is, while a far better engineer than Edison, as good a businessman and publicist.

   For some months he has been teasing technophiles on the net with his proposal for a transport system from Los Angeles to San Francisco that would be faster than air, more "environmental" than trains and far cheaper than either. He called this Hyperloop.

   A few days ago he unveiled the concept.
Hyperloop plans

The Register says:

"The plans call for a low-pressure tube mounted on pylons and stretching between the two cities which would fire transit capsules floating on air bearings down the line at speeds of up to 760mph.
Hyperloop would use prefabricated steel tubes for the route, which would be partially evacuated to a fraction of outside air pressure to reduce friction. Musk said he looked into running the system in a vacuum tube, but determined that it would be incredibly costly and highly vulnerable to leaks.

But having air in the pipes means each transit capsule would be pushing a column of the stuff in front of it, so the design calls for a battery-powered compressor in the head of the vehicle which sucks in that air and feeds it into air bearings that keep the tube from touching the tunnel and provide enough thrust to outweigh the loss of speed from air friction.

 .....speeds of around 300mph before the route reaches the current I5 freeway. Once on that long, straight route, it will be boosted up to 760mph before slowing against at Los Angeles

Hyperloop could be built directly above the freeway, Musk suggests, to cut down on the amount of land needed for the system, and where the route does cut across private land, the worst the landowner would have to deal with would be support pylons for the tubes every 100 meters. A 15-mile tunnel section would also be needed to get through the hills surrounding Los Angeles".

   But they conclude it is doable and the $6bn (£4 bn) price tag is optimistic but not inconceivable. Probably building it over the freeway helps get the cost down a lot.

   I was quite surprised that he isn't aiming for complete vacuum in the tubes. Total vacuum means no frictional losses and in theory no upper speed limit.  Musk is officially  aiming for a very low air pressure - as low as present technology can guarantee. In a tube air produces a bigger barrier than it would elsewhere because there is nowhere for it to get out of the way to. However in the detailed description he says air pressure would be "1/6 the pressure of the atmosphere on Mars .... an operating pressure of 100 Pascals, which reduces the drag force of the air by 1,000 times relative to sea level conditions and would be equivalent to flying above 150,000 feet altitude" which, if it isn't a perfect vacuum is as close as most of us are ever going get to one.

    This looks like what is practical now. Someday we will be able to build the full vacuum tube system in tunnels across, or rather under, continents. Because pure vacuum tunnels will be faster they will have to be very straight whereas the route given for this has a limited number of bends.

    But doable is doable.  
SpaceX and Tesla CEO Elon Musk reveals designs for 700 mph Hyperloop

   So why is this in a magazine about Scotland?

   Well while Musk's thoughts were inspired by California having a high speed rail project costed at $60 bn we in Britain, not to be outdone, have our own High Speed 2 project at £45 bn (& rising) which will take till 2032 (and rising) to reach Manchester and Leeds and then to proceed to Scotland in the far mists of futurity at an additional cost.

     Even more insanely the SNP are promising a Glasgow/Edinburgh HS (admittedly only 140 mph) by 2024. Last time the Lab/SNP government promised this it was costed at £3 bn but presumably costs have risen since then.

    But hyperloop shows that what so many had thought a white elephant has now become a white dinosaur.

    There was a good argument that cars would remain more practical than HS2 unless your destination was the station itself. A better one that air travel to Leeds and certainly Scotland, would remain both cheaper and faster. But it is rail and rail is officially good and deserves massive subsidy.

     But now we have a rail system that will be faster, 10 times cheaper and at the technological cutting edge.

     Another alternative is to do it by tunnel the whole way. That would cost more but not that much more. The Norwegians have been cutting tunnels at £4 million per km and it would certainly be much less for long tunnels cut near the surface. That suggests 2 lane of tunnel to Leeds would be about £3 bn. Glasgow-Edinburgh £500 million. Both on top of normal hyperloop engineering costs. Since a tunnel doesn't intrude on the environment, without all the expensive delays caused by Swampy.

       It looks like about £4 bn for HS2 as far as Leeds, £7 bn by tunnel as opposed to a minimum of £3 billion. In Scotland £600 m for Glasgow-Edinburgh, £1.1 bn by tunnel as opposed to at least £3 bn by conventional (slower) rail.
       Lets go for it. Britain, particularly Scotland has some of the world's best engineers. Wouldn't it be nice if, as we did a century and a half ago, we did something at the technological cutting edge? Particularly if, as better technology usually proves, it costs less.

     I am not saying that Hyperloop is, without some finessing the complete answer but I am saying that it, or waiting a few years till it is perfected, is more than 10 times more sensible than going for a conventional high speed link which is clearly going to be obsolete long before it is built.

     I did send links involving this to a number of politicians. The only one to reply was Christopher Monckton, UKIP's Scottish leader. He said:

I've been following the hyperloop notion with some interest. There's actually a cheaper way of doing it, because maintaining a vacuum is not only expensive but dangerous. One uses guide-rails not only below but also above the train, leaving plenty of space between the train and the tunnel wall, allowing the air to flow easily. You can still do the speed of sound in safety, and the upper guide-rails prevent the lateral acceleration that is otherwise the curse of all rail travel (e.g. the Tay Bridge disaster). Let us continue to oppose the HS2 white elephant, but consider putting together a consortium to build a subterranean X-rail system from Wembley yards to Falkirk: the heart of London to the heart of Scotland in under an hour. 
Running-cost as well as build-cost are crucial, it is really cheaper to do without a vacuum if one can. There is also the Safety First principle: if there is a breakdown one wants to be able to get the passengers out without breaching the walls of the tube to get at the capsule inside. 
    I didn't mention the Glasgow-Edinburgh proposal because I didn't realise the SNP had been silly enough to reinstate it. However it seems to me that this would be an opportunity for Scotland to show the rest of the country how to do it. You want a shorter project before going for a trans-Britain line. If only the SNP had the gumption.

     I will differ from Lord Monckton in hoping it goes to Glasgow. That may be Glasgow chauvinism but it can also be that the Scottish Tunnel Project, if it made the western Isles and Kintyre easily accessible by road, would put Glasgow at the centre of Scotland.

     I doubt that there is a single Scottish MSP or MP who would even know what the Hyperloop is let alone be competent to discuss the engineering. I should mention that like Monckton I am a member of UKIP but on the other hand I have previously acknowledged the Conservative John Redwood as having made an informed and sensible suggestion about rail - that the weight of carriages and thus rail transport costs, could be greatly reduced if they were built with the modern technology used in buses rather than the Victorian technology that still dominates rail travel.

     Both those gentlemen are the exception that proves the rule. That we are ruled by main party leaders who are not only ignorant but revel in their ignorance. I doubt if anybody sane would claim the leaders of any of our main parties are among the better intellectuals the country has. Which explains much of what is wrong and could be easily cured in this country. 


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Hi Neil Sandy here ( I commented on the vac train when you first mentioned it ) I don't know Lord Monkton's engineering qualifications, but producing and maintaining a near vacuum ( even space in earth's orbit is not a true vacuum as there are still quite a few atoms to be found )is neither difficult nor dangerous. There are pipelines traversing the country who operate at a much larger pressure differentials than one atmosphere. The key to high speed and low energy is to eliminate, or reduce as much as practicable friction forces in both the support and propulsion of vehicles carrying passengers and / or freight.
If your figures for tunneling are correct, a high speed Glasgow to Edinburgh tunnel going down about 200 meters could , using gravity alone reach speeds well over 200kph, giving a journey time city centre to city centre of under 40 minutes. This might be a good pilot project to help develop the technology and give Scotland a much better export potential than wind turbines
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