CTA is adding bus and rail service to the marathon start and finish in Grant Park on Sunday, as well as to the race expo at McCormick Place on Friday and Saturday. The transit agency also has listed on its website a dozen CTA stops that are close to prime viewing areas along the 26.2-mile route.
Marathon participants and spectators are urged to allow extra travel time and to purchase fares or passes well ahead of time.
Sunday will mark the 40th Chicago Marathon. More than 40,000 people are expected to participate, and each year about 1.7 million spectators turn out to view the event.