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
- 30 more...
- ItemWerkema049 - Northern Pacific 3600 in Minneapolis, Minnesota, in 1968.
- ItemWerkema050 - Northern Pacific 3612 in Auburn, Washington, in 1968.
- ItemWerkema051 - Northern Pacific 5405A and 5400D in the Portland, Oregon, in 1965.
- ItemWerkema052 - Northern Pacific 5409D in Auburn, Washington, in 1963.
- 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.
- 16 more...