Railroad Archives Online
- CollectionD0063 - Walter W. Ainsworth Collection
- Series004 - Northern Pacific Railroad Company
- Subseries Level 1014 - Photographs
- Subseries Level 2001 - Railroads--Equipment and Supplies
- Subseries Level 3003 - Freight Cars
- ItemWWANT105 - Northern Pacific railcars at Lake Union in Seattle, Washington, circa 1925.
- ItemWWANT106 - Northern Pacific railcars at Lake Union in Seattle, Washington, circa 1925.
- ItemWWANT213 - Northern Pacific steam locomotive 1682 near Black River, Washington, circa 1925.