The 1972 Chicago commuter rail crash, the worst in Chicago's history, occurred during the cloudy morning rush hour on October 30, 1972.
Illinois Central Gulf train 416, made up of newly purchased Highliners, overshot the 27th Street Station on what is now the Metra Electric Line, and the engineer asked and received permission from the train's conductor to back the train to the platform. This move was then made without the flag protection required by the railroad's rules. Unfortunately, his train had cleared automatic block signals which cleared express train 720, made up of more heavily constructed single level cars, to continue at full speed on the same track. The driver of the express train did not see the bilevel train backing up until it was too late. When the trains collided, the front car of the express train telescoped the rear car of the bilevel train, killing 45 people and injuring 332.
After the accident, the ends of most commuter rail cars and locomotives in the Chicago area were painted with orange and white stripes for better visibility.