The progress of a few recent trains as measured by the railroads shows how the delays occur. Among them was a coal train traveling 1,100 miles east from the Powder River Basin in Wyoming.

The train reached Chicago in 60 hours; its average speed, with delays for traffic control and a delivery schedule on the first leg, was 18 miles per hour. Within the “corral” of the greater Chicago area, the average speed dropped to 3.9 miles per hour, the pace of a rapid walk. It took more than 10 hours to move the 40 miles across the city. It had to stop completely on the outskirts of town during commuter rush hours and wait its turn at “interlockings” — go-slow rail intersections like the one at Englewood. Once outside Chicago, the train’s average leapt to 36 miles per hour.

Some of the causes of delay might have seemed outdated in the 20th century, much less the 21st, like manual switches that engineers have to throw after their trains have passed. Create is replacing them with electronic switches and online traffic control networks, but until then engineers at some points have to get out of their cabins, walk the length of the train back to the switch — a mile or more — operate the switch, and then trudge back to their place at the head of the train before setting out again.

Chicago had lived with its rail anachronisms and idiosyncrasies for decades, but everything fell apart in a 1999 blizzard that paralyzed the city’s rails and backed up train traffic across the United States for months.