Railroad Archives Online
- CollectionD0170a - Cascade Rail Foundation Walt Ainsworth Photograph Collection
- Series002 - Chicago, Milwaukee, St. Paul, and Pacific Railroad Company
- Subseries Level 1014 - Photographs
- Subseries Level 2003 - Railroads--Buildings and Structures
- Subseries Level 3007 - Tunnels
- ItemWWAMP1988 - West portal of the Milwaukee Road tunnel at Rockdale, Washington, undated.