The Pink Line (Douglas-Loop Service) is a rapid transit line in Chicago, run by the Chicago Transit Authority (CTA) as part of the Chicago 'L' system. It began operation for a 180-day trial period on June 25 2006, running between 54/Cermak Station in Cicero, Illinois and the the Loop in downtown Chicago. The CTA has since added two six-month extensions to this trial. The route to the Loop follows tracks shared with Blue Line trains on the Douglas branch and Green Line trains on Lake Street, connected by the previously non-revenue Paulina Connector.