Tip #2: Book a new ticket Behind walking or biking, taking a train is by far the most sustainable travel option available. A trip by plane results in more CO2 output than taking a train by more than 800%. Seriously. Sure, it'll take longer, but imagine how much more you'll see along the way. The world is covered by hundreds of train routes that take you through some of the most scenic areas on the planet – places you otherwise would never see. If you're looking to travel sustainably, it's definitely worth a try!