This one is a single span Warren Truss bridge, date of construction and history unknown. Apparently it is on the Pend Oreille Valley Railroad which connects to both the Union Pacific Railroad and the Burlington Northern and Santa Fe Railroad. This bridge is about 250 feet in length, including 100 or so feet of steel girder extensions at each end. It rests on a pair of large concrete piers while the extensions rest on concrete abutments. There are fifty two Warren Truss bridges in Idaho, all, or almost all, being railroad bridges.
Coordinates given are at the nearby highway bridge.
Warren
Another very common bridge type in Idaho (and the nation) is the Warren truss. This design is characterized by the diagonal members carrying the compression forces and the vertical members in tension; therefore, the diagonal elements are more substantial and give a "zigzag" appearance in elevation. Like the Pratt, the simple versions incorporate parallel top and bottom chords. The distinction between Pratt and Warren can be remembered by visualizing the compression posts as forming a series of "W"s signifying "Warren."
Warren trusses are generally configured such that the diagonal (compression) members meet at the top and bottom of the tensile verticals which form one panel. Some variations occur, however, where the diagonals cross two or three panels thereby forming what are termed "double-intersection" or "triple-intersection" Warren trusses. Generally found as railroad bridges, these variants are rare in Idaho and particularly rare as highway structures.
Like the Pratt and its variations, the Warren bridge type can be found in through-truss or pony-truss forms, and occasionally as a deck truss.
Fifty-two Warren variation bridges are identified in the 1982 survey and inventory
From the Idaho State Government