From the Chicago Sun-Times:

An Amtrak train on its way from Chicago to Detroit was delayed for more than six hours because of a flat wheel Sunday night.

Wolverine Line train No. 354, carrying 254 passengers, was scheduled to depart Chicago at 6 p.m. and left about 30 minutes late, according to Amtrak spokesman Steve Kulm.

About 10 miles outside of Chicago, the train stopped and the crew found a “flat spot” on a coach car, which is similar to a flat tire, Kulm said.

Instead of continuing on to Detroit, the train returned to Chicago at 10:25 p.m. and went to the maintenance yard to replace the car.

About 12:30 a.m., the train returned to the station to allow any passengers who wanted to get off the train to do so, Kulm said. As of 1:30 a.m., the train was en route to Detroit.

During the delay, the train maintained power and staff passed out free water and food, Kulm said.

Source: http://www.suntimes.com/news/metro/23834338-418/amtrak-train-with-flat-wheel-delayed-six-hours.html