Comment Re: Remote exploit? (Score 1) 48
Nothing prevents someone from maliciously dangling a battery-powered or solar-powered, cellular-capable pod off the edge of a highway bridge that crosses a railroad track and being half a continent away when actually triggering it.
Except that as the train passes under bridge, it will momentarily interrupt the brake signal, yes, but as the train slows down it will go away from the transmitter and likely get far enough away to restore the signal and the train brake signal will be restored, so the train keeps going...
(Train brakes aren't like throwing an anchor from a ship, they take time to stop the train.)
Yes, you could attach the transmitter to the train, but, really, what's the point?
You're assuming you can't transmit the signal for at least half the stopping distance of a train. If you can, then you start transmitting at half the stopping distance, and it will stop before it leaves the signal range.
In practice, one mile of range would likely be enough for even the heaviest trains.