Railroad Archives Online
- CollectionD0255 - Casey Adams Collection
- Series004 - Northern Pacific Railroad Company
- Subseries Level 1014 - Photographs
- Subseries Level 2001 - Railroads--Equipment and Supplies
- Subseries Level 3001 - Steam Locomotives
- ItemCRAGNS208 - Northern Pacific Steam Locomotive 12, undated
- ItemCRAGNS240 - Northern Pacific Steam Locomotive 666, undated
- ItemCRAGNS242 - Northern Pacific Steam Locomotive 916, undated