Courtesy of PRT Consulting of Colorado, Peter Muller's great simulation comparing PRT to light rail. Visualizes a hard to explain concept. Click to start.
SWE (aka Taxi 2000) with a recent video of their wireless control system showing many simulated vehicles in operation at their Minnesota facility.
Any fool can make things bigger, more complex, and more violent. It takes a touch of genius -- and a lot of courage -- to move in the opposite direction.