I’ve always thought “The Old Patagonian Express,” Paul Theroux’s book about his trip from the U.S. down to South America by train, was one of his best. I’ve sometimes wondered what became of the old train he writes about near the book’s end—the one he seized on for the title. It turns out, it’s still operating . The same starkness of place that struck Theroux in the high Patagonian desert remains. Like a photograph from an earlier era, the train and the landscape remain unchanged.