A dining car (American English) or a restaurant car (British English), also a diner, is a railroad passenger car that serves meals in the manner of a full-service, sit-down restaurant.
It is distinct from other railroad food service cars that do not duplicate the full-service restaurant experience, such as cars in which one purchases food from a walk-up counter to be consumed either within the car or elsewhere in the train. Grill cars, in which customers sit on stools at a counter and purchase and consume food cooked on a grill behind the counter are generally considered to be an "intermediate" type of dining car.
Before dining cars in passenger trains were common in the United States, a rail passenger's option for meal service in transit was to patronize one of the roadhouses often located near the railroad's "water stops". Fare typically consisted of rancid meat, cold beans, and old coffee. Such poor conditions discouraged many from making the journey.
Most railroads began offering meal service on trains even before the First Transcontinental Railroad. By the mid-1880s, dedicated dining cars were a normal part of long-distance trains from Chicago to points west, save those of the Santa Fe Railway, which relied on America's first interstate network of restaurants to feed passengers en route. The "Harvey Houses", located strategically along the line, served top-quality meals to railroad patrons during water stops and other planned layovers and were favored over in-transit facilities for all trains operating west of Kansas City.
As competition among railroads intensified, dining car service was taken to new levels. When the Santa Fe unveiled its new Pleasure Dome lounge cars in 1951, the railroad introduced the travelling public to the Turquoise Room, promoted as "The only private dining room in the world on rails." The room accommodated 12 guests, and could be reserved anytime for private dinner or cocktail parties, or other special functions. The room was often used by celebrities and dignitaries traveling on the Super Chief.