Rambling across the landscape aboard a luxury train was once the zenith of cutting-edge, sophisticated travel. Trains are no longer the fastest way to reach a destination, but they’re as stylish as a private jet and much more romantic. (Even if Agatha Christie had lived to see the 21st century, can you envision her writing Murder on the Boeing 787 Dreamliner? Of course not.) Top-of-the-line trains continue to clatter across six continents. If anything, losing the speed race to the airlines has made luxury train travel a greater status symbol because it demands a wealth of time as well as money. And make no mistake — riders place a premium on luxury. If you want the choicest sleeper cabins on a train journey, you might need to book two years in advance.