Behind that fame, however, there's infamy. America's leading nerve center for rail movement is also its leading train traffic choke point. It takes a freight train as much time to get from New York to Chicago as it takes to get through Chicago. The ripple effects slow Amtrak and Metra service almost daily. And no point of congestion in Chicago — in the country, for that matter — is worse than the tangled knot of freight and passenger lines known as the 75th Street Corridor.