They don't build them like they used to. Already up for replacement:
Contract No. 63598 Kane County District 1 Section 06-00214-18-RP FAP Route 361 (IL 25) Project HPP-1527(37)
Project consists of replacing the structure carrying the UP Railroad over IL 25, the construction of a temporary shoo-fly structure to carry the UP Railroad over IL 25, the construction of a structure to carry IL 25 over the East Branch of Brewster Creek, roadway widening and reconstruction, traffic signal modernization and drainage improvements, located at the north approach to Brewster Creek to Dunham Road and the intersection of IL 25 at Gilbert Road;
As Nathan previously suggested, this bridge has been replaced. I suspect this bridge was too narrow for the area (Stearns Road and IL Route 25 are both busy roads). I'm almost certain this modern span found a new home, as needed by the railroad.