Northern Pacific 40.5-foot, box car number 8130 with plug and sliding doors is on a siding at Denver, Colorado, on June 6, 1978. The car is part of the 8000-8449 number series. Photo by GJ Werkema. Other subject classes: freight car, steel box car

Northern Pacific 50-foot, box car number 5211 with plug and sliding doors is on a siding at Boulder, Colorado, on February 14, 1965. Photo by GJ Werkema. Other subject classes: freight car, steel box car

Great Northern Flatcar 69730 at Boulder, Colorado, June 15, 1965, Association of American Railroads Class FM. Other subject classes: Flat car

Great Northern Flatcar 66066 at Boulder, Colorado, July 14, 1965, Association of American Railroads Class FM. Other subject classes: Flat car

Great Northern Flatcar 60108 at Boulder, Colorado, June 15, 1965, Association of American Railroads Class FMS, bulkhead. Other subject classes: Flat car

Great Northern Boxcar 6788 at Boulder, Colorado, June 6, 1978. Other subject classes: Box car

Great Northern Boxcar 48827 at Boulder, Colorado, January 24, 1965, double wood sided 40 foot boxcar. Other subject classes: Box car

Great Northern Boxcar 48827 at Boulder, Colorado, January 24, 1965, double wood sided 40 foot boxcar. Other subject classes: Box car

Great Northern Boxcar 41612 at Boulder, Colorado, June 17, 1965, 50' single wood sided, 2 sliding doors. Other subject classes: Box car

Great Northern Boxcar 41612 at Boulder, Colorado, June 17, 1965, 50' single wood sided, 2 sliding doors. Other subject classes: Box car