Well, it's gotta be around 100 miles. Example.......Chicago-Cleveland= 312 miles. Amtrak has 3 trains per day: One takes 5h 49m and the other two take 7h 05m. The airlines offer a total of 20 flights per day with a flight time is 1h 14m.There's a certain distance range, maybe under 500 miles, where train can save you time. .