Railroad Archives Online
- CollectionD0036 - George Werkema Collection
- Series003 - Great Northern Railway Company (U.S.)
- Subseries Level 1014 - Photographs
- Subseries Level 2001 - Railroads--Equipment and Supplies
- Subseries Level 3002 - Diesel Locomotives
- 219 more...
- Itemimg87 - Great Northern Diesel Locomotive 640 at Superior, Wisconsin, 1975
- Itemimg88 - Great Northern Diesel Locomotive 682 at Lewistown, Montana, 1965
- Itemimg89 - Great Northern Diesel Locomotive 685 at Hillyard, Washington, 1965
- Itemimg9 - Great Northern Diesel Locomotive 122 at Saint Paul, Minnesota, 1971
- Itemimg90 - Great Northern Diesel Locomotive 688 at Interbay, Washington, 1961
- Itemimg91 - Great Northern Diesel Locomotive 688 at Wenatchee, Washington, 1968
- Itemimg92 - Great Northern Diesel Locomotive 715 at Wenatchee, Washington, 1969
- Itemimg93 - Great Northern Diesel Locomotive 732 at Wenatchee, Washington, 1968
- Itemimg94 - Great Northern Diesel Locomotive 905, undated