A collision between two commuter trains in Chicago occurred during the cloudy morning rush hour on October 30, 1972, and was the worst such crash in Chicago's history. 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. The train's crew had not used a flagman before, and while it was a prescribed practice, it had fallen out of use. Instead, the conductor and the engineer worked in concert to back up the train, with the curve in the track partially blocking the view.

The Illinois Central Railroad, sometimes called the Main Line of Mid-America, was a railroad in the Central United States. Its primary routes connected Chicago, Illinois, with New Orleans, Louisiana, and Mobile, Alabama, and thus, the Great Lakes to the Gulf of Mexico. Another line connected Chicago west to Sioux City, Iowa (1870), while smaller branches reached Omaha, Nebraska (1899) from Fort Dodge, Iowa, and Sioux Falls, South Dakota (1877), from Cherokee, Iowa. The IC also ran service to Miami, Florida, on trackage owned by other railroads.