Railroad Archives Online
- FondsD0036 - George Werkema Collection
- Cyfres003 - Great Northern Railway Company (U.S.)
- Is-gyfres014 - Photographs
- 001 - Railroads--Equipment and Supplies
- 006 - Cabooses (Railroads)
- Eitemimg193 - Great Northern Caboose X47 at Wenatchee, Washington, 1968
- Eitemimg194 - Great Northern Caboose X63 at Denver, Colorado, 1971
- Eitemimg198 - Great Northern Caboose X101, 1970
- Eitemimg199 - Great Northern Caboose X101, undated
- Eitemimg200 - Great Northern Caboose X101, undated
- Eitemimg201 - Great Northern Caboose X105 at Wenatchee, Washington, 1988
- Eitemimg205 - Great Northern Caboose X224, undated
- 16 mwy...