service until the end of steam in Britain in the early 1960s. The designer of the BR Standard Class 9F locomotive as well as the rest of the BR standard classes as Chief Mechanical Engineer of British Railways, Robert Riddles, originally designed the aforementioned locomotive to be a 2-8-2 using the boiler from one of the 4-6-2 passenger locomotive standard classes. However, he later decided to use a 2-10-0 wheel arrangement with a new boiler design, as it offered more tractive effort and better weight distribution. United States The 2-8-2 saw great success in the United States, mostly as a freight locomotive. In the 1910s it largely replaced the 2-8-0 Consolidation as the main heavy freight locomotive type. Its tractive effort was similar to that of the best 2-8-0s, but a developing requirement for higher speed freight trains drove the shift to the 2-8-2 wheel arrangement. The Mikado type was, in turn, ousted from the top-flight trains by larger freight locomotive wheel arrangements such as the 2-8-4, 2-10-2, 2-10-4 and articulated locomotives, but no successor type became ubiquitous and the Mike remained the most common road freight locomotive with most railroads until the end of steam. More than 14,000 were built in the United States, about 9500 of these for North American service, constituting about one-fifth of all locomotives in service there at the time. The heaviest Mikados were the Great Northern's class O-8, with an axle load of . Almost all North American railroads rostered the type, notable exceptions being the Richmond, Fredericksburg & Potomac, the Boston & Maine, the Delaware & Hudson, the Western Maryland, the Cotton Belt and the Norfolk & Western. The largest users included the New York Central with 715 locomotives, the Baltimore & Ohio with 610, the Pennsylvania Railroad with 579, the Illinois Central with 565, the Milwaukee Road with 500, the Southern with 435, and the Chicago, Burlington & Quincy with 388. A number of North American 2-8-2s have been preserved as either static display pieces, or steam excursion stars. These include Baltimore and Ohio 4500, Nickel Plate Road 587, Grand Trunk Western 4070, Southern Railway 4501, Grand Canyon Railway 4960, Spokane, Portland and Seattle 539, Southern Pacific 745, Tremont and Gulf 30, Duluth and Northern Minnesota 14, Soo Line 1003, McCloud Railway 18, McCloud Railway 19, and Pennsylvania Railroad 520. Yugoslavia Borsig built 2-8-2s were delivered to the railway of the Kingdom