Vehicle: Rail
Newton's Cradle (Train) Cars   (+5)  [vote for, against]
Save brake pads (and avoid fancy gizmos) and starting energy for frequent trains and never have a station trainless.

Exterior springs are mounted at the front and back of each train car, which is reinforced along its length.* When a train approaches, the station sends it info on the weight of the incumbent train, whose doors are closed to prevent the slicing of people halfway in the door (who, if they happened to be bakers, would otherwise become 2 halfbakers). In both trains a message pipes, "Ensure that your belongings are securely fastended and brace for impact in 5, 4, 3..." One train propels the other forward (so that it does not need to accelerate) and retains enough momentum to bring it forward to where the other train was. So there's always a train (or a few cars) at the station.

There could even be a bunch of trains all transferring momentum to the last train in the line, but this would only work in Germany (see *). One exciting aspect is that stations can have different numbers of cars waiting, and the frequency of arrivals and departures can me modulated through nonlinear track systems (more cars come in from other tracks, just as they do in real train systems).

No longer just a satisfying click from the desktop model- now only second in regularity and enjoyment to the local clock tower!

*If the country in question is Germany, they could forget the springs and just build the frames very strong and enjoy getting the two cars to smash (damagelessly) into one another in mechanical and temporal precision. Now THERE's something by which to set your watch!

Not so good: High G-forces/jerk/whiplash during train arrivals and stops (no sleeping on the train, or riding on the top a la India). Many trains needed, with many operators to pay unless computers replace the operators.
-- Ketchupybread, Jun 05 2007

worm_20train [hippo, Jun 05 2007]

or cat's cradle http://www.ifyoulov.../chten_cats1105.htm
[po, Jun 05 2007]

A bun for the laugh, anyway.

Really, keeping the acceleration within human-tolerable bounds would either require extremely slow trains, or extremely long springs on the ends of the trains.

Incidentally, there's very little riding on the tops of trains in India nowadays, because almost every route is now electrified with overhead supply. You still get people hanging on the sides, though.
-- Cosh i Pi, Jun 05 2007

Would work well on a circular railway, such as London's Circle Line underground railway. It's also similar to my 'worm train' idea (link) where every segment (or carriage) of a continuous train alternately compresses and expands to move people along.
-- hippo, Jun 05 2007

I'd watch this in action, kinda reminds me of William George Crush's stunt, although in reverse.
-- skinflaps, Jun 05 2007

You could have a system with a flywheel like the toy cars you get with a toothed strip that you pull out to spin the wheels. The incoming train would have a sprung toothed pole sticking out the front that would mate with a hole in the stationary train and spin the flywheel.
-- marklar, Jun 05 2007

A (+) for the wonderful image you just created in my mind.
-- awesomest, Jun 05 2007

random, halfbakery