This bridge was originally built in 1869 to connect the Berlin Mills Railroad with Cascade, NH. It would receive maintenance in 1924 with the portal bracing being replaced and the substructure being redone in concrete.
In 1946 Elwyn E. Seelye & Co. did a Rehabilitation/strengthening of the bridge. Prehaps because of wartime constraints on steel a complete rebuild was not practical, leading to a more unorthodox method for its rehabilitation. The entire upper chord and endposts were encased in a steel tube and welded shut, several tension members had additional steel welded to them, the footing was encased in concrete, the entirety of the overhead & portal bracing was replaced with plain steel tubing, and a supplemental lower chord was added.
Whats left (visually) of the original bridge is the truss web verticals and diagonals. The verticals are standard 4 piece Phoenix columns , and it looks like the diagonals are original (with some having added material). The lower chord is still original, with pin connections at the bottom with no changes visible. It appears that the floorbeams are also authentic, as they are riveted and suspended from the lower chord.
The bridge appears to be quite safe as it carries several pipes across the Androscoggin, with new ones being added recently. Its unknown exactly when rail service ceased across this bridge, but the rails have long since been removed and wood planks added to make a driving surface.