I'm with you Matthew......this is indeed a rare pinned Warren pony truss. Heavy, built-up diagonals and NO verticals whatsoever. A no-doubter here!
All of the pinned Warren's that I have seen are from the 1880's. Engineers and designers would come to realize that the pin wear on these spans was a major concern, and the Warren truss would all but disappear until after the turn of the century. It was then that gusset plates and the practice of bolting and subsequently riveting trusses together would revive the Warren truss.
Although Warren through trusses would never begin to match the popularity of their Pratt counterparts, riveted Warren ponies would become a staple of small bridge construction after about 1910.
I THINK THIS IS A RARE FIND, from looking at the pictures it looks like it would make a wonderful walking bridge once it was restored. I love old 18 and 1900s bridges.
Definitely one that needs to be saved!
Wow this is a rare bridge, very nice find!