Musk announces plans to build Hyperloop demonstrator

Walt built a monorail doesn't make it a practical form of transportation. Building a solar to liquid fuel pilot plant would do far more for the environment.

I'm wondering how short a distance would be economically viable. In particular using this techonology for the 140 mile strech of the proposed High Speed 2 link between London and Birmingham? The initial estiamted cost of that was around 50 billion and rising. Seems may as well have a radical shift if we're going to spend that much...

The Hyperloop may be a pipe dream in some people's eyes, but kudos to Elon Musk for putting his money where his mouth is. I bet there are places that would welcome the opportunity to build it.

Makes a great deal of sense for cargo transport.

The beauty of this system is that, by travelling in a vacuum and using maglev, your capsule becomes almost capable of perpetual motion. Once it has been accelerated up to speed it coasts the rest of the way without any energy input needed. Using rail gun technology it should be possible to accelerate a lightweight capsule at, say, 1g (0 - 60 in 2.7s, a Porsche 911 can do that) without the power demand getting totally over the top. From this point on I'm going to go metric as it's simpler to do the calculations.
Assuming that we want a speed of 1600Km/hr. (1000 mph). We first convert to metres per sec m/s. This gives us a speed of 444.4m/s. , which at an acceleration of 10m/s/s (2% more than 1g, but who's quibbling?) will take 44.4s to achieve over a distance just under 10 Km, or about 6 miles.
As already stated, once we have achieved this speed the capsule will coast the rest of the way, until we need to slow it down to stop it hitting the buffers at 1000mph!
This acceleration will require a decent amount of energy. Assume we have capsules that weigh 2Tonne. The total energy required to accelerate this mass up to 1600Km/hr is 197.5 MJ, which averages out at 4448KW for the 44 seconds. Unfortunately, it's not quite as simple as that as in the early stages it will require less power but as we build up speed we will need ever increasing amounts of power to maintain our 1g acceleration. In the last second of acceleration we will need to be supplying power at the rate of about 8787KW (11600hp).
Now comes the good news, and it is good news. Remember that deceleration that we need to stop us at the end of the journey? The best way to achieve that is to have another rail gun at the other end. Only, this one works in reverse, and instead of putting Megawatts of energy into it, it generates Megawatts of energy as it takes energy from the capsule. In a perfect theoretical system it would be able to convert all the energy that went into accelerating us at the beginning of the journey back into electricity. Of course this is not a perfect world and so we would only get a proportion of it back. But, given the high efficiency of electrical systems generally, we could expect that with the right development work this might be as high as 80%. I say might.
There are at least three reasons for using individual capsules, rather than conventional trains. Firstly, the power required is proportional to the mass (weight). If we try to use trains we will require much beefier electrical systems to accelerate all that mass, systems that will be sitting idle during the half hour, say, between trains. If we send 10 seater capsules every 45 seconds that will amount to a 200 seat train every half hour. The second reason to use capsules concerns safety. At 1000mph there are unlikely to be any survivors if, for example, there was a serious breach of the tube. Using smart control systems so that each capsule knows the position, state and speed of all the other capsules in the tube, it should be possible to limit any catastrophic disaster to just one capsule. The third reason that I can see for using individual capsules is that it will lower the loading on the structure, making it possible to lengthen the span between supports.
There is nothing about this proposal that is beyond our present technology. I can't see any reason why development costs should be any higher than for a new airliner, and while infrastructure cost will be high they should be well within reach, particularly if an existing transport corridor can be used.

The Hyperloop does not need to prove the engineering they need to work out the logistics. Moving millions of people 28 passengers at a time will be a nightmare. This has the same problem as most transportation systems, "how do you get over 300 people and their luggage into the station on to the train car every hour, when you have 300 people coming in on the trains needing to get out of the station out to their final destination".

Love to see it run on these routes: LA to NY Denver, New Orleans, Miami, Memphis, Toronto, St Paul MN & or from NY to LA, Denver to Santa Fe or Houston or Sedona AZ
Be huge If safe to travel & escape in emergencies etc.
Like to see fullsize mockup at LA CA Auto show, Be awesome

@SPW78.
Yes, I agree, it would be a good idea to consider something radical for this vastly expensive project and I can't see any reason why it shouldn't be economically viable over a shorter distance. There are a few things that can be done to reduce costs.
1). Reduce the speed. If we bring the speed down from 1000mph to 620mph, then the length of rail gun needed at each end of the track is reduced by over 60%. Since this is the most expensive part of the track to build, and, since we'll still be able to go from Euston to New Street in a tad under 15 minutes, it seems sensible to sacrifice a little bit of speed for a 60% saving in this area. 2). Reduce the cross-section area. If we do this to the same as a small car, then we will be able to use a similarly smaller "pipeline". This will save costs in a number of ways. The effort to maintain a vacuum will be reduced. The whole structure will be lighter, enabling greater spacing between support columns. If we arrange the N and S tubes vertically with a space between them and truss framing connecting them then we can make the whole structure into an immensely rigid girder and increas the spacing between support piers.
3). Where possible use existing transport corridors. By building the track as an overhead system it should be possible to use existing corridors for a fair proportion of the length. Where this is not possible land purchase could be minimised if the overhead rail enjoyed similar conditions to electricity supply, which simply pays a rent to land owners for placement of pylons and access.
How about Gizmag Brits form a lobby group to promote this as a viable alternative to the relatively slow white elephant currently proposed.? Get support from the right scientific and technological brains and get it on the agenda. It's environmental, social and energy/carbon advantages are evident to anyone who applies a bit of thought.
Next stop - Kings Cross to Waverly in 55 minutes? London to Paris in 35?

Musk doesn't use his own money. He uses tax payers' money. This idea is impractical; I know it, you know it, Musk knows it, but idiots in the government bureaucracy don't know it.