Hyperloop

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?

If we are to make a massive investment in a new transportation system, then the return should by rights be equally massive. Compared to the alternatives, it should ideally be:

  • Safer
  • Faster
  • Lower cost
  • More convenient
  • Immune to weather
  • Sustainably self-powering
  • Resistant to Earthquakes
  • Not disruptive to those along the route

Is there truly a new mode of transport – a fifth mode after planes, trains, cars and boats – that meets those criteria and is practical to implement? Many ideas for a system with most of those properties have been proposed and should be acknowledged, reaching as far back as Robert Goddard’s to proposals in recent decades by the Rand Corporation and ET3.

Unfortunately, none of these have panned out. As things stand today, there is not even a short distance demonstration system operating in test pilot mode anywhere in the world, let alone something that is robust enough for public transit. They all possess, it would seem, one or more fatal flaws that prevent them from coming to fruition.

Constraining the Problem

The Hyperloop (or something similar) is, in my opinion, the right solution for the specific case of high traffic city pairs that are less than about 1500 km or 900 miles apart. Around that inflection point, I suspect that supersonic air travel ends up being faster and cheaper. With a high enough altitude and the right geometry, the sonic boom noise on the ground would be no louder than current airliners, so that isn’t a showstopper. Also, a quiet supersonic plane immediately solves every long distance city pair without the need for a vast new worldwide infrastructure.

However, for a sub several hundred mile journey, having a supersonic plane is rather pointless, as you would spend almost all your time slowly ascending and descending and very little time at cruise speed. In order to go fast, you need to be at high altitude where the air density drops exponentially, as air at sea level becomes as thick as molasses (not literally, but you get the picture) as you approach sonic velocity.

Continue Reading, Hyperloop-Alpha.pdf

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Comments

offworld@ymail.com

Good engineering ideas, needing different implementation.

A lot of the hyperloop design I think most people would agree with, but there are a number of things that need some serious thought ... some as simple as human factors engineering with the lack of bathroom access in the tightly confined "smaller" passenger capsules for long periods of time. This suggests that both passenger and auto/freight tubes are the same larger size.

There need to be three tubes, not two ... so one can always be taken down for service without breaking the loop .... peak times can offer extra capacity in one direction for a while, possibly alternating every few hours.

Much of the costs are logistics in acquiring right of way, plus clean up after construction to restore right of way, combined with lingering visual eyesore issues of another huge man made object being visible as far as the eye can see in both directions.

A submerged floating tube off the coast in shallow water would vastly simplify obtaining right of way, and provide a natural level grade without extensive expensive boring. The tube can be constructed to be nearly neutral buoyancy, with each section having several small bladders to actively control depth ... including surfacing long sections as needed for servicing.

Construction is probably best done in a harbor with a rail spur for concrete and aggregate delivery, using a dedicated concrete batch plant. Using multiple below grade dry docks, 100ft sections of continuous extruded reinforced concrete would form each tube section. Fully robotic finishing machines would reduce labor and improve quality. Once cured and tested, end caps can be applied, the dry dock flooded, and the section towed to the installation site where it would be joined to the active end of the project.

Each end of the tube sections would have a fine surface finish with multiple O-ring seals, much like large diameter concrete water/sewer pipe. A combination of anchored tethers, and submerged support pylons to position the tube. more?

nokobike@yahoo.com

I have one semiMagLev system , cheaper to MagLev by 80-100 time . And can go by 2.000 km/h , ticket can by 0,2 eurocent/2 tone/km . Now i work for perfected the actual system for 10.000 km/h . My phone number is 0040/725/422-927 , Romania country , Timis county , Timisoara City .

robheus

The hyperloop would be the ideal system if all trafic would be confined to just going from point A to B. Unfortunately, there are many more points from which people depart from or want to arrive at. You would not be able to connect all those points with a hyperloop system. The problem with the hyperloop is that (unlike a train system) you can not switch lanes. Even more, if you want to service not only points A and B, but also some point in between A and B, with a hyperloop it would be impossible to stop at that point and then go the the final point B, because that would block ongoing traffic, so for intermediate stops, you would already need two different tube systems (and for the return trip, also 2 tube systems). So this means that apart from indivual lines (connecting let's say a big city with an air port, or two major cities) the hyperloop goes nowhere. A combination of a hyperloop with an airport would be ideal. You could do the check-in and all security checks etc. before you enter the hyperloop, and after that, you can directly enter the flight.
But it is not going to grow into a country spanning network. So a highspeed rail network like the chinese built is much more practical, because then you can connect different individual lines, create branches, etc, and in the end span all major cities in the country.
The chinese now going to built a direct highspeed rail link connecting Moscow and Bejing. Estimated travel time: 2 days.