1920s, which was expensive at the time. Warm dishes, such as soups and sauces, were usually prepared at a small stove in the restaurant carriage's kitchen. On busy days, prepared steaks were delivered from rail depots. Otherwise, the menu consisted largely of fish options, such as halibut, flatfish, cod and even whale sausages. The kitchens were staffed by two maids and one attendant. Blocks of ice were often used instead of refrigerators. With the opening of the Dovre Line, Spisevognselskapet established dining-car service on 25 June 1921. In 1921 a train ride from Kristiania to Trondheim lasted approximately 15 hours, and the average waiting time at each station was between 10 and 15 minutes. On 1 July 1925 dining service was introduced on the Valdres Line, from 1 July 1926 on the Brevik Line, from May 1934 on the Nordland Line and from 15 May 1936 on the Røros Line. In 1948 210,000 meals were served on board, in addition to sandwiches and drinks. The company also offered a light breakfast on night trains on the Kongsvinger, Østfold and Dovre lines. During the Second World War, dining-car service was discontinued. After the war trains faced competition from aviation and automobiles, and serving trolleys were installed on Norwegian trains. In 1965 cart service on trains was centralised and standardised; food service was faster, and prices were lowered. In the 1970s cafeteria cars were used, where passengers could serve themselves. Restaurants NSS derived most of its revenue from the operation of restaurants at railway stations; in 1939, this amounted to 80%. Initially, the company operated the restaurant at Oslo Ø; from 1921, it also took over operation of the restaurants at Oslo West Station, Hamar, Koppang, Opdal and Elverum. The following year, four more restaurants were added: Støren, Myrdal, Dokka and Hell. NSS also established its first kiosk, at Bergen Station. In 1923, the company was allowed to take over all restaurants in the railway districts of Oslo and Hamar; by 1925, it had taken over operation of the restaurants at Lillehammer, Hønefoss, Jessheim, Kornsjø, Halden, Ski, Eidsvoll, Otta, Dombås, Åndalsnes, Kongsvinger, Trondheim, Rena, Roa, Ringebu, Bjorli and Finse. After this NSS decided not to obtain many additional restaurants, as it did not see value in such a strategy. From 1930 through 1934 the company took over restaurants at Ål, Jaren, Lillestrøm and Tønsberg, along with dining service on the steamship Skibladner,