2 . The busiest choke point for train traffic in North America is here in Chicago.1,300 trains a day-one-quarter of all rail traffic in the U.S.-move through this city, including six of the seven biggest railroads in the country. Almost anything traveling from coast to coast comes through here, where train traffic has become so tangled (缠结的) that old railroad hands like to joke it takes trains three days to get from Los Angeles to Chicago, and three more to get through Chicago.

The massive traffic is made worse by the fact that the region’s busy commuter (通勤者) rail systems must compete for limited track space with the nation’s largest freight (货运) lines. Chicago operates 750 Metra trains a day that transport hundreds of thousands of passengers to and from the city alongside dozens of Amtrak trains carrying thousands more. An agreement reached between the city and the railroads gives commuter trains the right of way during the morning and evening rush hour.

The city’s train traffic is also an annoyance for residents. Russell Bartmes, who lives on the north side of Chicago, says one of the most congested points he sees is in nearby Schaumburg, where cars can sit for 10 minutes to let trains pass. “That shouldn’t happen,” Bartmes says. “It’s really a situation that cries out for some dollars.”

A major fix is already under way. An ongoing project -Chicago Region Environmental and Transportation Efficiency (CREATE) Program — is designed to untie the train lines and allow the rail network to operate more efficiently. So far, 28 completed projects have worked by adding rail lines, removing tracks from street level by creating overpasses and underpasses, and separating freight and commuter trains. Because of Chicago’s vital role in sending goods around the country, a more efficient rail system could have positive effects around the U.S.