Most people think of the train as a 19th century relic - but for visionaries around the world, the potential of trains is unlimited, and may be the key to solving our most stubborn problems. New designs and technologies will bring us trains that travel at jet speed, that float above tracks made from pure air, and that tunnel right through the planet. Meet the innovators who are creating hydrogen-powered trains, magnetic levitation trains, fluffy tracks, and tubular rails. And in the distant future, you may even ride a gravity train that cuts though the earth to get you anywhere on the planet in under an hour.
