Railroad Archives Online
- CollectionD0237A - Great Northern Railway Historical Society Cascade Division Collection
- Series003 - Great Northern Railway Company (U.S.)
- Subseries Level 1006 - Business Correspondence
- ItemGNRHSCD344 - Great Northern 6 AM Situation Reports from Seattle, Washington, June 1965
- ItemGNRHSCD345 - Great Northern 6 AM Situation Reports from Seattle, Washington, October 1964
- ItemGNRHSCD346 - Great Northern 6 AM Situation Reports from Seattle, Washington, October 1965
- ItemGNRHSCD347 - Great Northern 6 AM Situation Reports from Seattle, Washington, September 1964
- ItemGNRHSCD348 - Great Northern 6 AM Situation Reports from Seattle, Washington, September 1965
- 4 more...