A recent wind storm has had a devastating impact on the Northwest Railway Museum's bridge 35. A large cottonwood tree that measures more than five feet at the base has blown over and landed on the structure. Estimates are that the tree weighs more than 12,000 pounds and the bridge was subjected to the entire force.
While the tree was intertwined with the bridge structure, damage appeared to be minor. Unfortunately, serious damage became obvious as soon as the tree was removed. Significant damage was sustained by the outer stringers, a pile cap, and some of the deck boards that support the ballast.
Bridge 35 brings the railroad into downtown North Bend and consists of a through-pin-connected Pratt truss and two segments of conventional wood trestle structure. The Pratt truss was first erected over the Yellowstone River in Montana in 1891, and moved to North Bend in 1924. However the damaged section is constructed of timber and dates from 1923. The last major work on this section was performed in 1964.
A bridge inspection and cost estimates are driving the repairs. The Museum blog will feature another post while repair work is underway.