2200s have been running on the Englewood-Howard and Lake-Dan Ryan Lines at the beginning of their lifes. CTA sometimes send 2200 series trains to run on other lines outside of the Blue(O-Hare-Logan Square-Milkawee-Dearborn Subway-Congress) Line as either historic charters or just tempoary trains(if the 2200 runs on the Red Line, it probaly won't run on the Red Line for more than a day). The answer that is the most likely, however, is there only in the Howard Yard for maintenance.
Hope this isn't the end for the 2200 series...yet....