
What Happened to Hovertrains? (2018) [video] - simonebrunozzi
https://www.youtube.com/watch?v=qUXEFj0t7Ek
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melling
@1:10 Trains in Japan were initially only running at speeds up to 130 mph in
1964.

Over half a century ago the world had bullet trains. I guess when we had 200
million Americans we didn’t think it was worth the effort. Now with an extra
130 million people, it’s too difficult and expensive.

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autokad
it will be more interesting if we ever get down the costs of energy, then we
can focus on really fast tech. its also worth noting that trains between
philadelphia and nyc (Acela Express) go ~135-165 mph.

if it takes 6 hours and ~ 450$ to get from nyc to sf, it would be more
revolutionary to reduce the cost by 50% than than cut the time in half I
think.

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dmix
Why are train tickets so expensive? I get long distances but it always seemed
so expensive to me.

For example I could go between Toronto-MTL by bus for $20-30 but by train its
$100-120.

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nkoren
Many reasons, but for a start, the roads are much more subsidized than the
rails are.

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scythe
It seems to me the fundamental inescapable problem with hovertrains was
simple: they’re loud. Sound is a pressure wave, hovercraft require high
pressures; therefore, they are noisy. Even if you solved momentum drag, track
maintenance, and everything else, nobody will let you build it near their
house.

(Maybe a maglev train could hover only at low speeds inside a station. Maglev
works better for moving trains rather than stationary ones. But then it’s not
a hovertrain.)

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klingonopera
TBH, I would've expected a Maglev train to "touch down" in a station, at least
that is what I would do if I were to have designed it...

Anyone here ever rode on the Maglev in China can provide more details?

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russdill
Just an engineering aside, you'd probably want braces to engage the train
rather than the train to lower. If it lowers you have to raise it before it
starts again which would require extra energy and substantial force.

~~~
klingonopera
I think a kind of "landing gear" would be preferable, as its operation could
be station-independent, which in turn centralizes maintenance, therefore
reducing running costs.

AFAIK, there currently isn't an actual Maglev network in operation (just
point-to-point - no traffic, no stops), but if there would be, I think it's
easier to have any train be able to stop anywhere on the track than to have it
stop at specific locations only.

But other than that, yes, you're definitely right that any change of elevation
of the entire train should be avoided as much as possible.

EDIT: I just realized, my last paragraph isn't necessarily true either, i.e.
compare the situation to start-stop-sytems on cars, there's a sweet spot in
efficiency, when turning off the engine and starting it would cost more than
letting it run all the time.

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chungleong
One thing I've been wondering is whether is possible to power a ground effect
vehicle from overhead wires. That would sort of be like a hover train. The
"tracks" would be cheap to build. Just need to compact the ground to a smooth
surface.

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fulafel
The need to constantly produce lift would probably consume a lot of energy.

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chungleong
Lift-induced drag goes down with the square of velocity. At high speed, the
need to stay aloft doesn't cost you that much.

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sureaboutthis
They will build (my perception) a hyperloop/maglev train between St. Louis and
Kansas City. [https://www.stlmag.com/news/missouri-could-be-getting-a-
hype...](https://www.stlmag.com/news/missouri-could-be-getting-a-hyperloop-
from-st-louis-to-kansa/)

