Railroad Archives Online
- CollectionD0153 - Doug Wingfield Collection
- Series004 - Northern Pacific Railroad Company
- Subseries Level 1014 - Photographs
- Subseries Level 2001 - Railroads--Equipment and Supplies
- Subseries Level 3011 - Railroad cars self-propelled
- ItemWingfield.162 - Northern Pacific Rail Diesel Car B-41 at Duluth, Minnesota, 1961