One of the greatest perks of train travel is the freedom it offers to get up, walk around, and enjoy the scenery while someone else does the driving. There’s no need to plan gas stops, pull over at rest areas, or book a hotel just to break up the trip. So if you’re looking to explore the northern part of the United States, hop aboard Amtrak’s Empire Builder. Running from Chicago to the Pacific Northwest, the Empire Builder covers more than 2,200 miles in about 46 hours. Along the way, the route passes major cities, small towns, open plains, winding rivers, and some of the most postcard-worthy landscapes in the country—including a stretch of Glacier National Park many consider a highlight. The Empire Builder also splits in Spokane, Washington, giving travelers the option to continue to Portland, Oregon, or head north to Seattle, Washington. It’s a pick-your-own ending that only adds to the appeal of this cross-country route.…