NEW YORK (MainStreet)Have you heard about the Hyperloop? If not, allow me to get you up to speed. The Hyperloop borrows ideas from a 1920s mailroom for transportation. The system, proposed by inventor Elon Musk of Tesla fame, would use an enormous pneumatic tube to rocket cabins on frictionless cushions of air at speeds of up to 800 miles per hour. Musk predicts that a trip from San Francisco to Los Angeles could take about 30 minutes. It's like the old intra-office mail, except for instead of small brass tunnels shuttling memos through the building, it uses giant aboveground tubes carrying aluminum cabins. In short, it's about the most futuristic way of getting from point A to point B we're likely to see until they finally get that teleportation thing right. Still, Musk's proposal for the Hyperloop put us here at MainStreet in mind of another, older form of transportation that also runs on pre-built lines: trains. They've been around for a very long time, but not all rail journeys are created equal. So, in honor of this writer's hopes of one day making it from Chicago to New York City in under an hour, here are the eight best train rides in the world.