Chicago o´hare
http://www.ohare.com/
> 4 domestic terminals (1-4)
> 1 International Terminal (Terminal Five)
Riding the ATS whithin the airport
The Airport Transit System (ATS) is a quick, convenient, and economical way to get around the airport. The ATS is a free, 24-hour rail system that operates between the three domestic terminals, the international terminal, long-term parking, and the Metra station.
The ATS is fully automated and spans 2.7 miles. It accommodates up to 2,400 passengers per hour. From beginning to end - Terminal 1 to Lot E - the travel time is just nine minutes.
Reach Chicago downtown by train
The Chicago Transit Authority´s (CTA) Blue Line provides 24-hour access between downtown Chicago and O´Hare International Airport. Trains run 8 minutes or less from 5 a.m. to 8 p.m. Monday through Friday, and every ten minutes from 5 a.m. to 11 p.m. on weekends. Currently, a one-way fare for the 45-minute ride is $1.75 and $.25 for a transfer.
The CTA station is located at the lowest level of the Main Parking Garage (next to elevator center 4) and is accessible by pedestrian tunnels located in Terminals 1, 2, and 3. From Terminal 5, take the Airport Transit System (ATS) to Terminal 3 and follow the signs.
For additional CTA information:
Phone: +1 312-836-7000
http://www.transitchicago.com/