Railroad Archives Online
- CollectionD0237A - Great Northern Railway Historical Society Cascade Division Collection
- Series001 - Burlington Northern Railroad Company
- Subseries Level 1014 - Photographs
- Subseries Level 2003 - Railroads--Buildings and Structures
- Subseries Level 3010 - Miscellaneous Structures
- ItemGNRHSCD047 - Burlington Northern (former Great Northern) Interlocking Tower "UD", Seattle, Washington, post-1980