Question: In what year did the railroad that built the High Bridge cease to operate?
Sentence (from "High Bridge (Latah Creek)"): High Bridge, a railroad bridge over Latah Creek in Spokane, Washington, was constructed in 1972 by the Burlington Northern Railroad, following that railroad's creation in 1970 through the merger of the Chicago, Burlington & Quincy, Great Northern, Northern Pacific, and Spokane, Portland & Seattle railways.
Relevant evidence: Yes