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
- Itemimg1 - Great Northern Diesel Locomotive 10, undated
- Itemimg10 - Great Northern Diesel Locomotive 131 at Hillyard, Washington, 1965
- Itemimg106 - Great Northern Diesel Locomotive 2505 at Savanna, Illinois, 1974
- Itemimg107 - Great Northern Diesel Locomotive 2505 at Chicago, Illinois, 1974
- Itemimg108 - Great Northern Diesel Locomotive 2506 at Interbay, Washington, 1967
- Itemimg109 - Great Northern Diesel Locomotive 2513 at Denver, Colorado, 1970
- Itemimg11 - Great Northern Diesel Locomotive 136 at Hillyard, Washington, 1965
- Itemimg111 - Great Northern Diesel Locomotive 3000 at Minneapolis, Minnesota, 1964
- 220 more...