About 1,000 feet of electrified third rail was knocked over by a train on the northbound CTA Blue Line tracks near the Rosemont stop Tuesday morning, causing an almost four-hour service delay, officials said.
The problem occurred about 7:15 a.m. Shuttle trains and buses were used between the Rosemont and O'Hare stations to get passengers around the affected section until full service was restored about 11 a.m., with some residual delays, transit officials said.
Part of a rail car called a trolley shoe made an improper connection with the third rail, which caused the third rail to lift from its correct position, said CTA spokeswoman Catherine Hosinski. The rail was then pushed over as other rail cars on the train traveled through the section, she said.
The train was removed from service for inspection, she added, and the affected portion of the track was repaired.
At their peak, delays of 20 minutes were reported along the line, officials said. Some riders said they experienced significantly longer delays.