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
- 49 more...
- ItemWerkema412 - Northern Pacific F-7 diesel locomotive 6015D and two B-units with a freight train on the mainline.
- ItemWerkema413 - Northern Pacific F-9 diesel locomotive 7003A enters a yard switch.
- ItemWerkema414 - Northern Pacific U-25C diesel locomotive 2523 at Tacoma, Washington, in 1968.
- ItemWerkema415 - Northern Pacific FT diesel locomotive 5400D at Portland, Oregon, in 1965.
- ItemWerkema416 - Northern Pacific F-3 diesel locomotive 6001A at Auburn, Washington, in 1968.
- ItemWerkema417 - Northern Pacific F-9 diesel locomotive 7008D at Spokane, Washington, on 1968.