Burlington Northern SD40-2 Number 6799, built November 1977; SD40-2 Number 6704, built December 1974; SD40-2 Number 6711, built February 1976; SD40-2, number unknown; passing Hoffman Avenue interlocking at Dayton's Bluff, Minnesota with blue-ended bathtub coal gondolas on June 4, 1981. Photo by Al Christianson.