During my first day of web surfing, I discovered that I'm not the only one interested in the many movable bridges in the Chicago area. In fact, others have already done what I had in mind---taking pictures and videos of Chicago's movable bridges: Chicago Loop Bridges and Historic Bridges. And Curious City has an interesting discussion of the bridge tenders and a couple of videos at the end. The first video is a nicely edited video of the full cycle of one of the road bascule bridges. The second video is an accelerated video of many of the bridges moving for a Spring sailboat run from the yacht yards to their Lake Michigan marina slips.
John Weeks III has taken pictures of the bridges and dams along the Mississippi, Illinois, and other rivers.
And I learned that there are others who are interested in taking pictures of bridges---Bridge Hunter and lazzo51---and Industrial Archeology. And some photographers can turn bridges into art: Mickey B., Joe Balynas.
Railfan blogs: Eddie's, Cool Train.
Flickr groups: Downers Grove, Homewood Railfanning.
Update: for railroad information in Chicago: Chicago Area Shortline Railroads, CHICAGO AREA RAIL JUNCTIONS