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
- 113 more...
- Itemimg354 - Great Northern Diesel Locomotive 501 at North Portal, Washington, 1970
- Itemimg356 - Great Northern Diesel Locomotive 507, 1967
- Itemimg357 - Great Northern Diesel Locomotive 503 at Minneapolis, Minnesota, 1970
- Itemimg358 - Great Northern Diesel Locomotive 509 at Askov, Minnesota, 1967
- Itemimg359 - Great Northern Diesel Locomotive 505 at Fridley, Minnesota, 1967
- Itemimg36 - Great Northern Diesel Locomotive 355A at Wenatchee, Washington, 1967
- Itemimg360 - Great Northern Diesel Locomotive 507 at Saint Paul, Minnesota, 1954
- Itemimg361 - Great Northern Diesel Locomotive 313C at Allouez, Wisconsin, undated
- Itemimg362 - Great Northern Diesel Locomotive 317A at Carlton, Minnesota, 1967
- 106 more...