In 1960 the Western Pacific made it possible to charter one of their RDC cars for excursions. The Zephyrettes early arrival in Oakland on Saturday and Sunday departure for Salt Lake City allowed the Bay Area Electric Railroad Association to sponsor a trip originating in Oakland and covering the soon to be abandoned Colusa branch of the Sacramento Northern. The trip ran over the WP to Marysville where Budd Car 376 switched over to the SN. Freight motor 653 met the excursion and pulled the car over the Feather River into Yuba City before the RDC continued on to Colusa. The date was March 26, 1960 and the photo was taken between Yuba City and Colusa. I'm don't know what the name of the creek is that the bridge spanned. Perhaps someone can help out with that info.