Hyperloop and other vactrains

This is vaguely a railroad - fixed guideway, point-to-point, etc. - so I guess discussion of Elon Musk's Hyperloop proposal and other vac-train (vacuum-tube-enclosed railroad) proposals can go here.

From CNBC:

Elon Musk tweeted Thursday that The Boring Company received "verbal" government approval to begin building an underground Hyperloop, saying it would take "29 minutes" to go from New York to Washington, D.C.

"Just received verbal govt approval for The Boring Company to build an underground NY-Phil-Balt-DC Hyperloop," Musk said.

He also floated SFO-LAX and DAL-HOU-SAS.

Just let the words 'verbal approval' sink in for a moment.

bdawe wrote:Just let the words 'verbal approval' sink in for a moment.

"Hey, Mr. Supreme Court Marshal, can I dig a hole and put trains in it?"

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The best thing about the Hyperloop proposal is that it already has the word "hype" right in it's name.

One would think that the beginning of production of the Model 3 (even if it's at a somewhat lower-volume schedule than promised even a few weeks ago*...), Musk would be going on and on about that.

I've seen the hypothesis that the Model 3 will be rather underwhelming. That Musk is pivoting to things like the Hyperloop right now doesn't do much to refute that hypothesis.

*: the Model 3 is still likely to be produced more quickly than the Viewliner II, let alone the Nippon-Sharyo order...

Here is how I look at this Hyperloop proposal.

In 1800 many people said the idea of the Erie canal was crazy, too complex, too expensive, will never happen.
In 1840 many people said the idea of a transcontinental railroad was crazy, too complex, too expensive, will never happen.
In 1900 many people said the idea of powered flight was crazy, too complex, too expensive, will never happen.
In 1960 many people said the idea of going to the moon was crazy, too complex, too expensive, will never happen.
In 2000 many people said the idea of widespread electric cars was crazy, too complex, too expensive, will never happen.
In 2017 many people said the idea of a hyperloop was crazy, too complex, too expensive, will never happen.

Scot

In that time, people also suggested flying cars, jet packs, Beech's Pneumatic Tube, the Cosmopolitan Railway, mass dirigible travel, ships made of ice and sawdust, and a great many other things that never really worked out. What you have presented to us is survivorship-bias

Have any details been released about evacuation of passengers in the event of an emergency in the tunnel?

Scot and Brendan: also remember that people thought electric cars were practical, briefly, at the turn of the 20th century before abandoning the technology for something better. I'm not convinced that Hyperloop won't suffer the same fate - being technically possible, but economically unnecessary and less useful than other tech.

Come to think of it, back then a lot of people thought steam-powered "horseless carriages" weren't feasible, and guess what--they were right.

Vactrains have been proposed for well over a century: Vactrain - Wikipedia

Robert Salter had worked on some proposals for the RAND Corporation:
The Very High Speed Transit System | RAND (1972)

Description of a very high speed transit (VHST) system operating in its own rarefied atmosphere in evacuated tubes in underground tunnels. Most cases considered took less time to go coast-to-coast (e.g., 21 min) than it takes an aircraft to climb to an efficient operating altitude. VHST's tubecraft ride on, and are driven by, electromagnetic (EM) waves. In accelerating, it employs the energy of the surrounding EM field; in decelerating, it returns most of this energy to the system. Tunnel systems would be shared by oil, water, and gas pipelines; channels for laser and microwave waveguides; electric power lines including superconducting ones; and freight systems. Environmental and economic benefits are substantial, and the technology for building and operating the system exists.

Trans-Planetary Subway Systems: A Burgeoning Capability | RAND (1978)

Describes a subway concept called "Planetran" comprising electromagnetically supported and propelled cars traveling in underground evacuated tubes, able to cross the United States in one hour. It is designed to interface with local transit systems, and the tunnel complex also contains utility transmission and auxiliary freight-carrying systems. Tunnels represent a major problem area and most of the cost. They will be placed several hundred feet underground in solid rock formations. It will require advanced tunnel-boring machines, such as hypersonic projectile spallation, laser beam devices, and the "Subterrene" heated tungsten probe that melts through igneous rocks. Planetran is rated as a system high in conservation of energy. For every car being accelerated, there is one decelerating in an adjoining tube. The decelerating cars return energy to the system. The tubes have a reduced atmosphere, making drag losses much smaller than for aircraft. Coast-to-coast energy costs are expected to be less than $1.00 per passenger.

RS proposed tunneling, and one can use existing hard-rock tunnels to get an idea of tunneling costs. From Gotthard Base Tunnel - Wikipedia, that tunnel is a pair of bores about 57 km long that cost around $10 billion in 2015 money. It took about 12 years to do the tunnel, with about 5 additional years for getting the tunnels ready for railroad service.

The GBT average tunneling rate was roughly 13 meters / 46 feet per day.

For the US, the distance between the two largest cities, New York City and Los Angeles, is about 2500 mi / 4000 km, 70 times the length of the GBT. So tunneling will either have to be (1) much faster, (2) in several locations at once, or (3) both.

It seems much easier to put the vactrain tubes on viaducts, with tunnels only in mountains and in urban areas. But that has problems of its own, like NIMBY objections.

It's one thing to fly nonstop coast to coast or even Washington to New York, but building a tunnel that skips intermediate stops would be a hugely expensive project to serve only one city pair. Build it to stop at intermediate cities and it might not be much, if any, faster than flying. Then you might have a trip of an hour or more with no bathroom. Somebody at some point is going to need one, so would the hyperloop then allow potty breaks at, say, Philadelphia or St. Louis? Nobody has thought it through. It's just words, which is what "verbal" means: spoken, written, or on a website, it's just talk.

Why wouldn't there be a bathroom aboard? It's Hyperloop, not SEPTA.

Somehow this technology seems more apropos in Europe, Japan, or China. American population density doesn't come as close.

scottychaos wrote:Here is how I look at this Hyperloop proposal.

In 2000 many people said the idea of widespread electric cars was crazy, too complex, too expensive, will never happen.

Scot

Interestingly, in the early 1900s, electric cars were fairly common, a fact I found, indirectly, from reading F Scott Fitzgerald novels.

Hyperloop would be very economical somewhere that already has plenty of natural vacuum.

For example that moon base we would have had by now if the Apollo program hadn't been cut.