The first diesel locomotives appeared on the Central Railroad of New Jersey in 1925 and on the New York Central in 1927. Since then, diesel locomotives began to appear in mainline service in the United States in the mid-1930s. Compared to steam, diesel power reduced maintenance costs dramatically while increasing locomotive availability. On the Chicago, Rock Island and Pacific Railroad, new units delivered over a year, compared with about for a mainline steam locomotive. World War II delayed dieselisation in the US until the late 1940s; in 1949, the Gulf, Mobile and Ohio Railroad became the first large mainline railroad to convert completely to diesel locomotives, and "Life Magazine" ran an article on 5 December 1949 titled "The GM&O puts all its steam engines to torch, becomes first major US railroad to dieselize 100%". The manufacture of new steam locomotives for stateside use decreased as dieselization continued. The Lima Locomotive Works was perhaps the last commercial builder of steam locomotives, with the final order completed being for ten “Berkshires” for the New York, Chicago & St. Louis Railroad in 1949. The last steam locomotive manufactured for general service in the United States would follow in 1953: a Norfolk and Western , built in the railroad’s Roanoke shops. 1960 is normally considered the final year of regular Class 1 main line standard gauge steam operation in the United States, with operations on the Grand Trunk Western, Illinois Central, Norfolk and Western and Duluth Missabe and Iron Range Railroads, as well as Canadian Pacific operations in Maine. The Grand Trunk Western did, however, use some steam power for regular passenger trains until 1961, the last instance of this occurring unannounced on trains 56 and 21 in the Detroit area on 20 September 1961 with 6323, one day before its flue time expired. The last steam-powered standard-gauge regular freight service by a class 1 railroad came little over a year later on the isolated Leadville branch of the Colorado and Southern (Burlington Route) on 11 October 1962 with 2-8-0 641. Narrow-gauge steam was used for freight service by the Denver and Rio Grande Western on the run from Alamosa, Colorado, to Farmington, New Mexico, via Durango until service ceased on 6 December 1968.