Railroad Archives Online
- CollectionD0036 - George Werkema Collection
- Series004 - Northern Pacific Railroad Company
- Subseries Level 1014 - Photographs
- Subseries Level 2001 - Railroads--Equipment and Supplies
- Subseries Level 3002 - Diesel Locomotives
- 34 more...
- ItemWerkema053 - Northern Pacific 6502C and 2501 in Livingston, Montana, in 1965.
- ItemWerkema054 - Northern Pacific 6504A and 6503D in Livingston, Montana, in 1965. .
- ItemWerkema055 - Northern Pacific 6511A in Minneapolis, Minnesota, in 1968.
- ItemWerkema056 - Northern Pacific 6704A in Minneapolis, Minnesota, in 1968.
- ItemWerkema057 - Northern Pacific Terminal Company 30 operating on the Lake Whatcom Railway at Wickersham, Washington in 2008.
- ItemWerkema058 - Northern Pacific Terminal Company 30 operating on the Lake Whatcom Railway at Wickersham, Washington, in 2008.
- ItemWerkema059 - Northern Pacific Terminal Company 30 operating on the Lake Whatcom Railway at Wickersham, Washington in 2008.
- ItemWerkema404 - Northern Pacific F-9 diesel locomotive 6706A at St. Paul Union Station in Minnesota in 1965.
- ItemWerkema405 - Northern Pacific F-7 diesel locomotive 6509C and the other three units at Livingston, Montana, in 1965.
- 12 more...