In 2007, CTA began a project to eliminate existing slow zones in the Dearborn subway that were having a major impact on travel time for riders. With the funds available at the time, CTA was able to make repairs that allowed trains to resume normal speeds. From July to September 2007, repairs were made to 6,336 feet of slow zones between the Damen and Clark/Lake stations. Crews replaced more than 5,000 deteriorated wooden rail ties with concrete rail ties.

Recently the CTA received federal stimulus funding that allows it to renew all of the remaining track (approximately seven miles or 39,000 feet) from Division on the O'Hare branch to Clinton on the Forest Park branch. Crews are replacing deteriorated wooden half ties with concrete half ties, running rail and contact (third) rail to remove emerging slow zones and help prevent the creation of new slow zones.