I've always had a fascination with trains, so when I'm in Chicago I try to use the elevated ('el' is the local term) for as much of my transportation as possible.  The el is really that -- much of the travel is  on tracks elevated above the street (though two of the main lines are subways in the downtown area and some lines are at street level in the suburbs).  The cars on the el are new and in good condition, but much of the rest of it is surprisingly old and looking to be in need of repair.  Much of the track and station system was built 80 or more years ago and has been maintained but not updated.  Downtown the el is on old metal trestles, most of the elevated stations do not have elevators or escalators, and lighting systems are frequently old.  BUT, it works and gets the working population around quite efficiently.

Stairs to a downtown el station

The same station in the early evening

About 11PM in the same station.

Onward on the el ->