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 3011 - Railroad cars self-propelled
- ItemWWANT019 - Northern Pacific gas electric motor car B-19 at Seattle, Washington, in 1938.
- ItemWWANT054 - Northern Pacific gas electric motor car B-19 at Seattle, Washington, in 1939.
- ItemWWANT083 - Northern Pacific gas electric motor car B-18 at Black River, Washington, circa 1935.
- ItemWWANT108 - Northern Pacific gas electric motor car B-18 at South Bend, Washington, in 1929.