Here are (4) Great Northern Reference Sheets from the Great Northern Historical Society. Reference Sheets include: 183 (December 1991) Great Northern's Cascade Division Snowsheds 1910 to 1929 Part 2, 184 (December 1991) Great Northern Wedge Snowplows, 185 (March 1992) Great Northern Snow Equipment Roster, 186 (March 1992) Great Northern GE U25B Road Diesel. Used and good condition. We combine shipping on multiple items.