Northern Pacific 43.5-foot, open, 3-bay, hopper car number 71104 in a yard at Albuquerque, New Mexico, on March 13, 1973. The car is part of the 71000-71499 number series. Photo by GJ Werkema. Other subject classes: freight car, open hopper car

Northern Pacific 43.5-foot, open, 3-bay, hopper car number 71022 in a yard at Albuquerque, New Mexico, on February 26, 1980. The car is part of the 71000-71499 number series. Photo by GJ Werkema. Other subject classes: freight car, open hopper car

Northern Pacific 43.5-foot, open, 3-bay, hopper car number 71022 in a yard at Albuquerque, New Mexico, in October 1978. The car is part of the 71000-71499 number series. Photo by GJ Werkema. Other subject classes: freight car, open hopper car

Northern Pacific 33.75-foot, open, twin hopper car number 70374 on a siding at Denver, Colorado, on August 26, 1973. The car is part of the 70200-70399 number series. Photo by GJ Werkema. Other subject classes: freight car, open hopper car

Northern Pacific 41.5-foot, solid-bottom, gondola car number 59440 in a train at Denver, Colorado, on September 2, 1973. The car is part of the 59000-59499 number series. Photo by GJ Werkema. Other subject classes: freight car, steel gondola car

Northern Pacific 41.5-foot, drop-bottom, gondola car number 58801 in a yard at Albuquerque, New Mexico, on November 25, 1979. The car is part of the 58750-58999 number series. Photo by GJ Werkema. Other subject classes: freight car, steel gondola car

Northern Pacific 41.5-foot, drop-bottom, gondola car number 58370 in a siding at Bellingham, Washington, on August 3, 1977. The car is part of the 58250-58749 number series. Photo by GJ Werkema. Other subject classes: freight car, steel gondola car

Northern Pacific 41.5-foot, drop-bottom, gondola car number 58352 in a train at Broomfield, Colorado, in September 20, 1976. The car is part of the 58250-58749 number series. Photo by GJ Werkema. Other subject classes: freight car, steel gondola car

Northern Pacific 41.5-foot, gondola car number 58299 in a siding at Denver, Colorado, in October 1974. The car is part of the 58250-58749 number series. Photo by GJ Werkema. Other subject classes: freight car, steel gondola car

Northern Pacific 65-foot, drop-end, gondola car number 56031 in a yard at Bellingham, Washington, on November 8, 2003. The car is part of the 56000-56024 number series. Photo by GJ Werkema. Other subject classes: freight car, steel gondola car