This bridge will probably be abandoned soon. The last customer on this track moved to Lebanon and CSX wants to rid itself of this spur. The bridge itself has a weight restriction (meaning that standard 286,000lb railcars cannot cross).
James L. Cooper's 1987 book, Iron Monuments To Distant Posterity, lists this as an Illinois Central bridge.
(I'm not sure if that's the line the bridge was originally constructed for, or if that's the line that was operating on the bridge at the time of the book's publication.)
Cooper's complete entry on this bridge reads as follows:
IC RR; White River
Pratt thru (3)
Keystone Br
Note: may be oldest extant RR truss; only Keystone Pratt; wrought iron; pinned; skewed; adjustable lower chord; portals.
There has been talk of wanting to make this into a trail bridge and if it is officially abandoned this would be the time to do so. There is already a trail that runs along the North end of the bridge. I will notify Indiana Landmarks Foundation about this possibility and see what they can find out.