Railroad Archives Online
- CollectionD0063 - Walter W. Ainsworth Collection
- Series004 - Northern Pacific Railroad Company
- Subseries Level 1014 - Photographs
- Subseries Level 2003 - Railroads--Buildings and Structures
- Subseries Level 3001 - Bridges
- ItemWWANT100 - Northern Pacific bascule bridge at Seattle, Washington, circa 1946.
- ItemWWANT101 - Northern Pacific bascule bridge at Seattle, Washington, circa 1928.
- ItemWWANT103 - Northern Pacific bascule bridge at Seattle, Washington, circa 1928.