Railroad Archives Online
- CollectionD0063 - Walter W. Ainsworth Collection
- Series002 - Chicago, Milwaukee, St. Paul, and Pacific Railroad Company
- Subseries Level 1014 - Photographs
- Subseries Level 2003 - Railroads--Buildings and Structures
- Subseries Level 3001 - Bridges
- ItemWWAPC0406 - Chicago Milwaukee and Puget Sound and Columbia and Puget Sound Railroad bridges at Maple Valley, Washington in 1911.
- ItemWWAPC0407 - Chicago Milwaukee and Puget Sound Railroad bridge at Maple Valley, Washington in 1911.