growing population that was "in permanent transit", frequently moving through different cities on business. George Pullman invented the sleeping car and the dining car in response to the needs of these people in the 1870s. Similarly, the English immigrant Frederick Henry Harvey was the first to use "dynamic mass movement" in restoring the Fred Harvey Company, which catered to the patrons of a chain of hotels located near railway stations, as well as offering catering, services, and high quality products on the trains themselves. Contemporary American society also witnessed the creation of new fast foods that originated from the traditional cuisine of various ethnic groups from around the world. For example, German immigrant Charles Feltman invented the hot dog in 1867 in his stall in Coney Island, New York by pairing a frankfurter with a bread bun. Imitators such as Harry Magley and Charles Stevens soon began selling hot dogs at New York Polo Grounds baseball games. Similarly, Italian immigrants sold ice cream from vending carts in the streets or pasta at their restaurants. Chinese immigrants initially opened restaurants to cater to their fellow Chinese-Americans, but they gradually became accepted by the American clientele, sometimes resulting in truly Chinese-American cuisine such as chop suey. In this diverse world of ethnic foods, the hamburger was able to rise to mainstream popularity and become a national food of the United States. White Castle System On November 16, 1916, chef and entrepreneur Walter "Walt" Anderson opened a hamburger stand in Wichita, Kansas, that used hygienic cooking methods, including grills and spatulas, and impressed his Wichita customers so much that many would become regular patrons. At this time, the hamburger was still not widely known by the American public. Anderson added onion rings to the burgers while they grilled, giving them a distinctive flavor. As demand increased, customers often bought his hamburgers by the dozen, giving rise to the company's subsequently popular slogan: "buy 'em by the sack". Despite some growth, Anderson had opened only four stands in the busiest areas of the city. In 1926, Edgar Waldo "Billy" Ingram collaborated with Anderson to open the first White Castle restaurant in Wichita. The restaurant was founded on the idea of cooking a hamburger quickly, giving it the honor of being the first fast food restaurant. Ingram soon realized that the word burger evoked connotations of circus performances at livestock markets and greasy pieces of