Railroad Archives Online
- CollectionD0063 - Walter W. Ainsworth Collection
- Series002 - Chicago, Milwaukee, St. Paul, and Pacific Railroad Company
- Subseries Level 1014 - Photographs
- Subseries Level 2001 - Railroads--Equipment and Supplies
- Subseries Level 3013 - Railroad Accidents
- ItemWWAPC0408 - Chicago Milwaukee St. Paul and Pacific Railroad accident at Maple Valley, Washington in 1950.
- ItemWWAPC0423 - Chicago Milwaukee St. Paul and Pacific Railroad accident at Maple Valley, Washington in 1950.