Railroad Archives Online
- CollectionD0036 - George Werkema Collection
- Series003 - Great Northern Railway Company (U.S.)
- Subseries Level 1014 - Photographs
- Subseries Level 2003 - Railroads--Buildings and Structures
- Subseries Level 3005 - Signals
- Itemimg1106 - Great Northern Order Board at Cashmere, Washington, 1987
- Itemimg1107 - Great Northern Order Board at Cashmere, Washington, 1987
- Itemimg1108 - Great Northern Order Board at Cashmere, Washington, 1987
- Itemimg1109 - Great Northern Signal at Bellingham, Washington, 1994
- Itemimg1110 - Great Northern Signal at Bellingham, Washington, 1994
- Itemimg1196 - Great Northern Sign at Baring, Washington, 1987
- 17 more...