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
- 4 more...
- Itemimg1110 - Great Northern Signal at Bellingham, Washington, 1994
- Itemimg1196 - Great Northern Sign at Baring, Washington, 1987
- Itemimg1197 - Great Northern Sign at Cashmere, Washington, 1987
- Itemimg1198 - Great Northern Sign at Delta Junction, Washington, 1982
- Itemimg1199 - Great Northern Sign at Dryden, Washington, 1987
- Itemimg1200 - Great Northern Sign at Ephrata, Washington, 1987
- Itemimg1201 - Great Northern Sign at Gold Bar, Washington, 1987
- Itemimg1202 - Great Northern Sign at Irby, Washington, 1987
- Itemimg1203 - Great Northern Sign at Leavenworth, Washington, 1987
- 10 more...