The basic boxcar was long the backbone of American freight railroading. These enclosed cars carried everything from foodstuffs, to raw materials, to manufactured goods. Later in the 20th century, standardized intermodal containers — which could be carried interchangeably on truck-trailer chassis or on railroad flatcars — replaced boxcars on U.S. railroads for many cargoes.

Flatcars are the simplest freight cars — little more than flat decks on railroad wheels. But they are highly flexible. Flatcars carry loads that are too large for enclosed boxcars — everything from industrial equipment, to farm tractors, to airplane fuselages. Specialized flatcars are vital to the trains that carry intermodal containers from marine terminals to distribution centers.

The caboose was the conductor's office, the crew's quarters, and — with its rooftop cupola or side-view bay windows — a place to spot problems on the train. But, unlike other cars in a freight train, the caboose didn't generate any revenue for the railroad. By the 1980s, new technologies and smaller train crews made cabooses unnecessary, and railroads quickly retired them.