This is the Deck Girder Bridge w/Open Deck Kit 85' Model Train Bridge in HO Scale by Micro Engineering.
Deck girder bridges are used by prototype railroads more frequently than any other type of bridge. They span everything from ditches to small rivers. These kits include X braces, lateral braces, rivet plates, bridge shoes and extensive molded-in details including rivet heads. The Open Deck Bridges include Bridge Flex-Track while the modeler's regular ballasted track runs across Ballasted Track Deck Bridges.