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"If it was first lifted to a height of 10 metres, the train could comfortably cover a distance of 400 metres".

By ascending 10m, you've managed to take the vehicle the distance from, in most European cities, one bus stop to the next. Sorry, "comfortably" from one bus stop to the next.

Well done, congratulations, have a medal.

"Imagine having a roller coaster ride as part of your commute to work... Now that would brighten up your day."

I have a good recollection, from part time work during my undergraduate years, of going into work work tired/a but groggy from the previous night/not quite sick enough to call in. And I've sat on a bus and cursed every slight slope or pothole or turn.

I am glad that on no such morning did I meet some chirpy technophile telling me that I really ought to be doing this on a rollercoaster, let alone an indirect one that stopped every 100m.

Edward Re

It clearly needs a few tweaks, but I love this idea!

Imagine an underground train with stations on the surface (spaced at 400m or your choice). The acceleration is more rapid, with less energy used. Less energy is lost while braking. You even save energy by not needing lifts to access the station platform.

Stations are visible and accessible. Right of way issues are a dream. You make the slope up and down as smooth as is needed.

If you are building an underground anyway, then this would cost about the same.

Traversing a mountain pass, or using it in an earthquake zone, may not work as well.


Please keep your hands in side the vehicle at all times...

I prefer the sci-fi idea of digging massive linear tunnels between cities. As the most direct route between any two cities is a path through the Earth, gravity will accelerate the train on its downward trek, proving lots of kinetic energy to get up the second half of the journey (assuming both stations have the same altitude). Of course, in practice motors will be required to complete the trip, as friction losses will not allow a completely motor-free journey.

But such things are fun to think about.

Joseph Alacchi

It is true that some subways, like Montreal, use gravity to assist acceleration and braking.

Now, to the New Scientist author, really you'll achieve speeds of 60kph with stops every 100 metres? Doesn't take a physics major to figure out you'll rip heads of people's bodies with that acceleration.

Miles Bader

It's pretty optimistic to think it just needs "a few small tweaks."

Even if an extremely pokey ('cause lets face it, it's never going to even approach 60km/h average speed) frequent-stop transit system based on a roller-coaster works in some limited circumstances, it's at best a replacement for some local buses. It's not going to work for longer distances (for the same reason pokey frequent-stop streetcars and local buses don't).

Even as a local-bus analogue, it's going to require a lot more infrastructure than a bus or streetcar for little apparent advantage, and with quite a few apparent problems...


EngineerScotty: With that method, assume no friction and a uniform Earth density, it takes exactly the same time - 42 minutes - to get from any place to any other on Earth, using absolutely no energy.

Unfortunately the method is completely impractical, due to both the high speeds, and the obvious difficulty of tunneling though the earth's magma.

But it's cool in theory.

Nate Wessel

I may have to tell the City of Cincinnati about this. It may not be too late to get this instead of the planned streetcar ;-)


I calculated that at a 10 in 400 (2.5%) slope, when a gravity-powered train reaches the first stop at 400 m, it would be doing about 23 kph.

Al Dimond

@Edward Re: On the surface you need ROW long enough for the platform and two portals into the ground at each stop. Have you ever seen a subway portal? Not exactly something you want at regular intervals in an urban environment.

Alon Levy

Eric: in practice, it's very hot rather than cool.

Andrew in Ezo

Well, given that it needs to be pulled up a slope anyway, why not just build a funicular, they have been transporting passengers comfortably for hundreds of years. Anyway, in Tohoku they will just go back to driving, with good 'ol buses, brt, and trains for those who don't or can't drive.

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