Vehicle: Mass Transit
Cannonball Trolley   (-1)  [vote for, against]
Cannonballs in a tube magnetically propel streetcars.

The concept is similar to cable cars, except instead of a flexible moving cable you have a fixed rigid plastic tube with steel [edit: aluminum balls would be better] cannonballs zooming in them. Instead of a clamp, you use powerful magnets in the floor of the streetcar to inductively drag against the cannonballs.

Periodically, linear accelerators or air blowers accelerate the cannonballs to keep them up to speed. In a sense, this system is like maglev, except that you only need sporadic linear motors, in convenient locations.

Air between the tight fitting cannonballs act as a cushion to minimize the impact of cannonballs running into each other.

Compared to cable cars, the cannonball tubes are low maintenance and the thrust is smooth. Instead of a sudden lurch from clamping down on the cable, thrust is smooth and gradual as the magnet is gradually strengthened (or lowered). The plastic tube has no exposed moving parts, and can even be buried underground for maximum safety.
-- IJK, Mar 17 2007

So, the streetcar (tram?) is going to magnetically glom on to these whizzing- along-in-a-tube steel balls?

Isn't the tram going to pick up a lot of drain covers, discarded paperclips, bicycles and other debris as it goes around town?

Also, what keeps the balls moving inbetween accelerators?
-- MaxwellBuchanan, Mar 17 2007


Maybe this wouldn't happen on a large scale, but if you've ever actually tried moving a paperclip around with a magnet underneath a table, it is anything but smooth.

More importantly, though, magnets like this would create way more force toward one another than they would forward or backward. So basically, you would need to apply the same motor or vacuum power as you did before to the cable for a cable car, except now you ALSO have to apply 3 or 4 times as much energy on top of that in order to overcome the ridiculous amount of friction occurring.
-- Smurfsahoy, Mar 17 2007


I hate trams. Could you point your cannon straight up please? Or straight down. Either is good.
-- the dog's breakfast, Mar 18 2007


The cannonballs move faster than the trams, so the thrust is smooth. There's a constant stream of fast moving cannonballs passing underneath a tram, so each one is only slowed down by a minor amount.

Also, I forgot about the ferromagnetic effect of using steel. Aluminum balls would work better, so only the induced magnetic drag effect is at work.
-- IJK, Mar 18 2007


How does an aluminum ball do anything at all? It doesn't create a magnetic field, so there is no electrical induction, and also there is no physical magnetic attraction from magnets on the trolley.
-- Smurfsahoy, Mar 18 2007


When a conductive material is moved near a strong magnet, there's a drag effect. Motion through a magnetic field induces currents which create an opposite magnetic field. A popular demonstration is to drop a strong rare earth magnet into a copper pipe or aluminum tube. It will drop notably slowly, due to this drag effect.
-- IJK, Mar 18 2007


Ohhhh, gotcha.

In that case, I suggest rings suspending down from the trams into the earth consisting of electromagnets. (much like the current clamps). Much more efficient usage of the cannonballs, still no moving parts, and you can stop if you want to still.
-- Smurfsahoy, Mar 18 2007



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