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
- 182 more...
- ItemWerkema313 - Northern Pacific hopper car number 75375 at Bellingham, Washington, in 1992.
- ItemWerkema314 - Northern Pacific hopper car number 75476 at Bellingham, Washington, in 1977.
- ItemWerkema315 - Northern Pacific hopper car number 75479 at Pasco, Washington, in 1990.
- ItemWerkema316 - Northern Pacific hopper car number 75672 at Hastings, Nebraska, in 1990.
- ItemWerkema317 - Northern Pacific hopper car number 75683 at Amarillo, Texas, in 1979.
- ItemWerkema318 - Northern Pacific hopper car number 76050 at Denver, Colorado, in 1976.
- ItemWerkema319 - Northern Pacific hopper car number 76216 at Denver, Colorado, in 1978.
- ItemWerkema320 - Northern Pacific hopper car number 76298 at Albuquerque, New Mexico, in 1980.
- ItemWerkema321 - Northern Pacific hopper car number 76318 at Kiona, Washington, in 1986.
- 32 more...