Central Michigan Saginaw River Swing Bridge
Photo taken by Douglas Butler
License: Creative Commons Attribution (CC BY)
BH Photo #286867
I can confirm that this bridge still carries trains. It probably hasn't operated as a "swing" for some time (who knows how long), but the railroad line is definitely still in use.
I was at the nearby Lee Mansion again today, and while waiting for volunteers to arrive so we could get to work on things, there was a train that went across. I was preoccupied because we were already past the intended start time, or Id've tried to get a few "train traffic" pictures.
I was looking at a map of Saginaw from 1937. I will link the site with the map in this comment. There appears to be another railroad bridge just north of this one right above Thompson street!
I can't find anything about the ST-Saginaw Bridge found by Douglas that crossed over Ojibway island however.
Oddly enough, there's a historic mansion just a couple blocks northeast of this bridge that is now the focus of a volunteer restoration project. https://www.facebook.com/CharlesLeeMansion/
Seeing this bridge out the window whilst in the mansion for a clean up day today, I decided to take a few minutes after we broke for the day to take a few pictures.
This bridge is still in use as of 9-27-13 and has been verified as still open!!!