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 3002 - Diesel Locomotives
- 6 more...
- ItemWingfield.172 - Northern Pacific Diesel Locomotive 6506C, 6503B, 6503C at Seattle, Washington, 1962
- ItemWingfield.173 - Northern Pacific Diesel Locomotive 6506C, 6503B, 6503C at Seattle, Washington, 1962
- ItemWingfield.174 - Northern Pacific Diesel Locomotive 6506C, 6503B, 6503C at Seattle, Washington, 1962
- ItemWingfield.175 - Northern Pacific Diesel Locomotive 6507C, 6511B at Marshall, Washington, 1968
- ItemWingfield.177 - Northern Pacific Diesel Locomotive 553 at Spokane, Washington, 1968
- ItemWingfield.179 - Northern Pacific Diesel Locomotive 312 at Marshall, Washington, 1968
- ItemWingfield.180 - Northern Pacific Diesel Locomotive 313, 862 at Spokane, Washington, 1968
- ItemWingfield.181 - Northern Pacific Diesel Locomotive 315 at Spokane, Washington, 1968
- ItemWingfield.182 - Northern Pacific Diesel Locomotive 373, 904 at Crookston, Minnesota, 1969
- 23 more...