From the CTA:

Southbound Red Line trains will temporarily operate on southbound Purple Line tracks at the Jarvis, Morse and Loyola stations from 10 p.m. each night to 4:30 a.m. the next morning beginning Monday, September 24 through Friday morning, September 28. Southbound Red Line trains will be unable to stop at the Jarvis, Morse and Loyola stations due to track maintenance work to eliminate slow zones.

Southbound customers who want to exit at Jarvis, Morse or Loyola should board a northbound train at Granville and ride back to these stations. Southbound customers who want to board at these stations should board a northbound train, exit at Howard and board a southbound train.

CTA customers are advised to allow extra travel time.

Northbound Red Line service is not affected. Normal southbound service will resume at Jarvis, Morse and Loyola at 4:30 a.m. the following morning.