A ubiquitous BNSF coal train from Powder River, Wyo. crosses the Missouri River between Mandan and Bismarck, N.D. on a very frigid Feb. day when the highest temperature reached was minus 16. Note the concrete against the eastward stone pier. Whereas N.P. bridge architect George Morison properly designed the bridge 131 years ago to withstand the force of ice jams and high water, the instability of the slope above the river's bank wasn't anticipated, and that led to decades of problems so much so that this bridge was considered for abandonment. Finally where the new steel and concrete trestle is N.P. removed a considerable amount of the hillside to reduce the slope and instability.