From the record
“The Route 66 Bridge over the Chicago, Rock Island and Gulf Railroad, in Wheeler County, Texas near Shamrock, Texas, was built in 1932. It now carries the south frontage road of Interstate 40 over the former Chicago, Rock Island and Gulf Railway right-of-way.”
Wikipedia article Route 66 Bridge over the Chicago, Rock Island and Gulf Railroad, CC BY-SA 4.0.
One of 18 National Register listings published here for Wheeler County · listed in 2007 · category: Structure.
Sources: the Wikipedia article · the case file at the National Archives · the National Register database, National Park Service · the Wikipedia article