This bridge and the rail line that passes over it have had an interesting and ironic history. The line was originally built by the Rock Island in the late 1800s as part of the Golden State Route through SE Iowa and onto Missouri, Kansas, Oklahoma, Texas, and into New Mexico.
In the 1930s & 40s, the line was heavily rebuilt through Iowa, with several new sections of track built that eased grades, had less curves, and shortened the line by several miles. Starting at Ainsworth, a new section of track was built that left the original main line and bypassed Washington. The new segment would branch off just before this bridge, thus a new bridge was built just south to carry the new main across North Fork Long Creek.
The original main line remained as a secondary branch line to Washington and points beyond. It would remain so until 1980, when the Rock Island ceased operations. The Milwaukee Road stepped in shortly afterwards to purchase the old Rock Island main from Muscatine to Ainsworth and the branch to Washington. This was done for two reasons: the original MILW route from Washington to Muscatine was partially built on a bluff and suffered from grades and stability issues, and there was also a new coal power plant being built at Fruitland along the RI tracks.
Thus, after around 40yrs as a branch line, the original Rock Island main would now be upgraded to a main line again, this time with the Milwaukee Road. Over the next 30yrs the bridge and rail line would change hands several times. The Milwaukee Road would only last a short while longer before being taken over by the SOO Line. The SOO would be just another in string of railroads the own the property, followed by the I&M Rail Link; Iowa, Chicago & Eastern; Dakota, Minnesota & Eastern; and finally Canadian Pacific.
How ironic that the new bridge to the south sits abandoned with its rails long gone, never to see another train pass over it, while just to the north this old bridge sees daily service as part of a Canadian Pacific main line?