A northbound Burlington Northern Santa Fe freight crosses the Wind River at Boysen, Wyoming, on July 7, 1999. The view is framed from inside an abandoned Chicago, Burlington and Quincy tunnel that once carried this main line into Wind River Canyon. This old alignment was relocated during the construction of Boysen Dam that began in 1946. Both U.S. Highway 20 and the CB&Q were relocated to bypass the construction site. The contract for the dam itself and the rerouting of the rail line was awarded to the Morrison-Knudsen Company, which built a 7,131-foot tunnel that actually ran under the dam and a portion of the reservoir. The new rail line opened in September 1950, with completion of the dam itself on February 16, 1952.