A Chicago & Eastern Illinois E7 backs down into Chicago's Dearborn Street Station to couple onto its' train. It carries a red flag indicating that this is the last section of multiple trains running on the same timetable... an oddity in the 1960's but occasionally seen when some large group wants to travel together and charter's a train.
This particular engine was a frequently seen in Chicago around this time each day [link]
From that photo you can see the Roosevelt Road bridge where I was standing when I took this shot. And vice-versa. In this shot you see the platforms where that shot was taken.