Don't underestimate kinetic energy of a train going 340 meters per second.

Sure.. but you can't hijack it, redirect it to another location, then crash it into a populated area.

You could perhaps... stop it?

And if you really want to cause havoc messing with trains, you go for cargo trains filled with hundreds of thousands of tons of toxic chemicals.

This sort of rational sensibility isn't going to stop the TSA from power-grabbing and mission-creeping their way into any new transportation system. They'll get their tendrils in the pie, sure as the sunrise. So will a million other government bureaucracies.

Yeah, I just meant energy is not the reason trains aren't used as weapons.

> Don't underestimate kinetic energy of a train going 340 meters per second

and then plowing into a strawberry field near Coalinga. Yeah, that's "a lot" of damage.

Depending on the train, you could level a downtown of a small city: http://www.ctvnews.ca/canada/two-more-bodies-recovered-from-...

Isn't the point that these things do not have much kinetic energy at all? The whole scheme wouldn't make sense if you still had to invest the same amount of power as for a conventional train.

Kinetic energy = 1/2 m * v^2. Hyperloop trains wouldn't have "much" less energy, because the scaling factor on velocity is so high that your savings on train weight don't mean much.

You are right that it would take less power.

Savings would be on the air friction, and the power you need to overcome it along the way.

...which can't be aimed at anything but the train station...

You'd be surprised. Just a week and a half ago ago a large section of Lac-Mégantic, a town east of Montreal, Quebec, was levelled by an unattended train that started rolling in the middle of the night. It was carrying a large load of oil, which ignited when the train derailed in the middle of the town.

http://en.wikipedia.org/wiki/Lac-M%C3%A9gantic_derailment