Would This High Speed Train Work?

Years ago, I read about a guy who designed a unique (low teck) high speed train. The idea was based around having cylindrical capsules running in an evacuated tunnels-the trains could attain speeds of 600 MPG, because the tunnel was a vacuum. The trains would be pulled along by electromagenetic induction (NOT MAGLEV)-just coils in the walls.
Would this work?

It’s not maglev, but there have been several attempts to build pneumatic tube trains. Someone tried to build one in Manhattan in 1870. I somehow seem to recall that it was in the news recently when new construction exposed a portion of it.

It would work, but the cost per mile of constructing and maintaining it would be stupendous. Here in the US we don’t even have Japanese-style high speed bullet trains, and AFAIK there are no plans to build any.

What advantage does this have over a true maglev train? If it is already using electromagnetic induction to move the train, wouldn’t contact with the walls of the tunnel just slow it down?

Sure it would work. Lots of things work on the level of engineering. Very often it is a chore making the economics pay off. (The transatlantic tunnel and terraforming Mars are my favorite examples.) We could do lots of things if we wanted to pay for them.

(How would passengers handle the acceleration and deceleration of such a train?)

Or being stuck in a vacuum?

Same way airline passengers deal with being stuck at low atmospheric pressure – sealed, pressurized cabin.

Low teck? :dubious: Not by a long shot.

I’m much more impressed with the idea of the nonstop train with detachable pods.

Unless you’re building an express over a long distance, a significant cost in both fuel and time is accelerating and decelerating the train. Building it so that it’s modular and only certain parts of the train start and stop would go a long way towards making things more efficient.

In addition, it doesn’t require any fancy technological improvements, evacuated tunnels or strong electromagnets, just some basic engineering. And it can be seamlessly integrated into the existing network because the train can continue to stop at any station that’s not fitted for a detachable pod.

Humans can withstand acceleration of up to 45 g. Doing so comfortably is a different question. :smack:


Less air resistance - which could be crucial if you want, say, to link two continents together, and don’t want to have to push a thousand-mile-long plug of air in front of you.

Wouldn’t it be easier to build powerful vacuum pumps along the line to evacuate the air as a train approaches (lowering the air pressure in front of it) and then refilling the tunnel after the train passes, giving the train an additional push?

Of course, it would be easier still and immensely cheaper to fill the air with 21st-century Concordes, but no matter.

Because the loading is compression, rather than tension as for a pressure vessel, the walls of a vacuum chamber need to be very stout. This scales non-linearly, so for a train sized tunnel, I’d wag you’d need steel walls at least 4" thick. That is one helluva lot of steel.

Oh yeah, if you want to use inductive drive, then the walls can’t be steel, or even a non magnetic conductor (eddy current losses)…so fiberglass maybe?

Rather than lots of pumps and ducts along the length of the tunnel, just have one pump in the train; sucks air in at the front, and blows it out the back.

I think that idea both sucks…and blows.

And maybe if the pump was powerful enough, you might not even need the track. That train could, I dunno, “fly” or something.

Was it filled with a river of slime? :wink:

Actually, from your link:

Just how old are you that 1912 is “recently”? :dubious: Maybe you should see if the screen name “Methuselah” is available. :smiley:

And if there was every an accident with one of these trains, one can be assured it would always be a recovery operation. If the massive deceleration didn’t kill the crew and passengers, the vacuum certainly would.

There would be no waiting for people to board or disembark. Here’s a video of a nonstop train network.

I saw something similar on some show about building a hypothetical trans-Atlantic rail tunnel. But I thought the trains were maglevs and would reach speeds of several thousand miles an hour in a vacuum.