The IEOC Line, Metrolink's sixth line to be introduced, opened in October 1995. As of July 2008, 8 trains in each direction serve the stations between Anaheim Canyon and Riverside on weekdays.
In July 2006, the Orange County Transportation Authority created weekend service on the IEOC and Orange County Lines. The IEOC Line schedule currently features 3 Saturday trains and 2 Sunday trains. However, in 2010, the Metrolink board voted to reduce service on the line.