I took this photograph. This bridge is over Sugar Creek on the ex-Monon RR (now CSX). My Dad & I went looking for the Monon trestle in Crawfordsville on Thanksgiving Day. He walked the trestle while I took photos. I am modeling this trestle in HO scale.
Jim Smith
Below this bridge on the banks of Sugar Creek is the largest public access site for fossils and criniods in the state of Indiana. You can just be walking and find fossils by looking down
According to Bird's eye view this bridge is located on the Montgomery County Sugar Creek Trail. The picture here is from 1972. The trail builders have totally changed the character of the bridge to make it safer for trail use. It no longer even remotely looks like the picture above.
Two bridges are confused here. The Big Four bridge was on the Peoria & Eastern RR, now gone. The Monon bridge was on the Monon RR and still carries CSX trains over Sugar Creek. It is not open to pedestrian traffic.