Railroad Archives Online
- CollectionD0153 - Doug Wingfield Collection
- Series001 - Burlington Northern Railroad Company
- Subseries Level 1014 - Photographs
- Subseries Level 2001 - Railroads--Equipment and Supplies
- Subseries Level 3006 - Cabooses (Railroads)
- ItemWingfield.51 - Great Northern Caboose X473 at Glacier Park, Montana, 1970
- ItemWingfield.52 - Great Northern Caboose X19 at Whitefish, Montana, 1970
- ItemWingfield.163 - Northern Pacific Caboose 10424 at Marshall, Washington, 1970