Railroad Archives Online
- CollectionD0036 - George Werkema Collection
- Series004 - Northern Pacific Railroad Company
- Subseries Level 1014 - Photographs
- Subseries Level 2001 - Railroads--Equipment and Supplies
- Subseries Level 3003 - Freight Cars
- ItemWerkema103 - Northern Pacific box car 1005 on a yard track in Denver, Colorado.
- ItemWerkema104 - Northern Pacific box car 1125 in March 1975
- ItemWerkema105 - Northern Pacific box car 1160 in Albuquerque, New Mexico in 1978.
- ItemWerkema106 - Northern Pacific box car 1220 in Albuquerque, New Mexico in 1980.
- ItemWerkema107 - Northern Pacific box car 1220 in Albuquerque, New Mexico in 1980.
- ItemWerkema108 - Northern Pacific box car 1229 in Albuquerque, New Mexico in 1978.
- ItemWerkema109 - Northern Pacific box car 1702 in Albuquerque, New Mexico in 1980.
- 216 more...