Railroad Archives Online
- CollectionD0011 - James M. Fredrickson Collection
- Series004 - Northern Pacific Railroad Company
- Subseries Level 1014 - Photographs
- Subseries Level 2003 - Railroad Buildings and Structures
- Subseries Level 3005 - Signals and Signs
- ItemJMF04-02400.0 - Northern Pacific dispatchers office at Tacoma, Washington, circa 1942.
- ItemJMF04-02401.0 - Northern Pacific dispatchers office at Tacoma, Washington, in 1943.
- ItemJMF04-02403.0 - Northern Pacific dispatchers office at Tacoma, Washington, circa 1943.
- ItemJMF04-02404.0 - Northern Pacific dispatchers office at Tacoma, Washington, in 1952.
- ItemJMF04-02405.0 - Northern Pacific dispatchers office at Tacoma, Washington, in 1957
- 66 more...