Trains and other vehicles that travel on rails and tracks have been around for hundreds of years. While most of these are for transport, roller coasters and a few others are just for fun!  Find out how maglev trains use magnets to reach speeds of more than 250 miles per hour. Discover what it's like to travel in a pod car, and learn how the world's wildest roller coasters live up to their scream-worthy rankings. See the most awesome rides on tracks and rails! Part of the Cool Rides series.