Work began today on the CTA’s Brown and Purple Lines.
The goal of the work is to to eliminate more than 2 miles of slow zones on between the Armitage and Merchandise Mart stations.
Rush-hour service will not be affected. Worl will be done mostly late at night and on weekends.
Trains will operate on a single track during these times, resulting in longer travel times and some occasional changes in boarding locations at stations, officials said.
Chicago Tribune contributed to this report.