Twenty-First Street Crossing was quite possibly the most complex junction in the Chicago area, with crossings through curved turnouts, crossings through crossings, and other esoterica to which only a low-level aerial photograph could really do justice. In this slide an Erie Lackawanna transfer run approaches on the Chicago & Western Indiana (below the now bare signal bridge) and is about to cross the Illinois Central's Iowa Line before curving to the left to cross the Pennsylvania (the two tracks to the left of the signal bridge). In the foreground are the joint Atchison, Topeka & Santa Fe and Gulf, Mobile & Ohio tracks, although in this post-Amtrak era Santa Fe trains will now curve towards the camera on the near tracks to reach the Pennsylvania's line to Union Station. Performing trackwork here must have been a near nightmare; this was a busy junction.
