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 3003 - Maintenance Facilities
- ItemWWASPSL6-084 - Northern Pacific Roundhouse at Pasco, Washington, undated