The Chicago Railways is a public transportation system in the city of Chicago, Illinois. It consists of eight rail lines and over 140 stations. The system is operated by the Chicago Transit Authority (CTA). The acronym ELS stands for 'Elevated Lines System', which is the name of the elevated railway system that serves the city of Chicago. This system was built in the late 19th century and is still in use today. It is one of the oldest and most iconic public transportation systems in the United States.