You can drive to this junction, but you'll have to pay a rapid transit fare to see it. So the best course is just to take a train here. The Chicago Transit Authority's Orange Line boarding platform at Ashland Avenue offers an excellent view of the junction. In downtown Chicago, Orange Line trains operate on the overhead "El" that loops around the downtown area. Take the train to the Ashland Avenue station and stay on the platform.
If you insist on driving, Take the Stevenson Expressway (I-55) to Damen Avenue. Then head northeast on Archer Road to Ashland. You can park in a shopping mall lot on the corner of Ashland and Archer. Walk across Archer to the station and buy a ticket.
Canadian National's ex-IC, ex-GM&O main line from St.Louis joins their ex-IC line from Iowa (CN owns the GM&O line between here and Joliet, Illinois; beyond Joliet it belongs to Union Pacific). The merged line proceeds east from here through 21st Street and 16th Street, then bends south at the lakefront to become the former IC main line. At one time, the Santa Fe main to Dearborn Station paralleled the Iowa line on the south, but it was abandoned years ago. This is a relatively busy place, with the GM&O line seeing the majority of traffic. Approximately 35 to 40 trains per day pass through here, including Amtrak's St.Louis trains and Metra's "Heritage" route trains to Joliet (the latter are rush hour only and do not operate on weekends). CN's Glenn Yard is southwest of here on the GM&O, and it is now their main Chicago terminal. Most freight traffic on CN originates or terminates there. Transfers and road trains between Glenn and the ex-IC Markham Yard near Homewood are a common sight here.
Until about 1990, Bridgeport was one of the least accessible junctions in the Chicago area, but with the construction of the Orange Line in the early 1990s, it's now just the opposite. The accompanying photo was shot from the CTA platform. The curving tracks at top are the Iowa line, the converging tracks are the GM&O and the CTA's outbound track is in the immediate foreground. Outside the photo to the right, the merged tracks cross a truss bridge over a canal that flows south from the Chicago River.
The only obstacle is the fare you must pay to access the boarding platform. Currently, the fare is two dollars, although it may be increased soon. While you're there, hop aboard a train and take the Orange Line rail tour.
Orange Line trains provide an excellent--if brief--view of six major junctions on their journey from downtown Chicago to Midway Airport. Departing the downtown area, the junctions are in order: 16th Street, 21st Street, Bridgeport, Brighton Park, 50th Street and 55th Street. Sit on the right side of the train if riding from downtown, the left side if travelling from Midway. Again, Orange Line trains may be boarded from the elevated tracks in the downtown area. If you board at the Van Buren / LaSalle station, you can circle the entire "loop" that encloses much of the downtown area. Orange Line trains run clockwise on the loop, traversing Van Buren Street on the south, Wells Street on the west, and Lake Street on the north before heading south on Wabash Avenue.