The role that train travel plays in the American popular imagination is an increasingly contradictory one these days, somehow deeply nostalgic and symbolic of the future at the same time. Getting from one city to another by train remains a thoroughly romanticized exercise — a humane relic of a more cosmopolitan and energy-efficient era in transportation. And yet trains have also become a key component of efforts by young planners, architects and politicians to re-imagine or revivify American ur