A Northern Pacific bridge book indicates that this structure was installed here in 1918, meaning it was relocated from another location. This other location is likely on the former NP mainline, hence the plaques stating the third crossing of the Yellowstone River.
I am President of a museum that celebrates the legacy of the Phoenix Bridge Company. We believe that this bridge was built by the company but need to know the year and other details about the bridge. www.phoenixvillefoundry.org is our web site.
Thank you.
Barbara Cohen
The Northern Pacific Railroad Research Library has been updating documents. This AFE (authority for expenditure) gives the original location of these trusses.
http://www.nprha.org/NP%20AFE%20scans6/0719-17.pdf?fbclid=Iw...