by "slower" they could only mean "run backwards"

Brown Line work to mean slower trains into Loop
Southbound service to be limited to one track at Belmont, Fullerton as of March 30
Will the living envy the dead?
Brown, Red and Purple Line riders will see a faster commute out of downtown but a slower one heading into the Loop beginning March 30... On March 30, the CTA plans to reopen another northbound track at the Belmont Avenue station. Currently, the Brown, Purple and Red Line trains share one track, which creates congestion as trains take turns accessing the station... At the same time, southbound service on those lines will be restricted to one track at the Belmont and Fullerton Avenue stations until June 30, 2009, or the onset of the end times, whichever comes later, as work begins on expanding those platforms and reconfiguring tracks.

"Unfortunately, it means that during construction, passengers will see longer commute times because trains (will be backed up during rush hours)," said CTA President Ron Huberman, who presented the changes Wednesday during the agency’s monthly board meeting.

The CTA will attempt to run a train every two minutes to help combat the congestion... (wait a minute... won't that make things more congested? ed.)