Under the Whyte notation, a 2-8-4 is a steam locomotive that has two unpowered leading wheels, followed by eight coupled and powered driving wheels, and four trailing wheels. This locomotive type is most often referred to as a Berkshire, though the Chesapeake and Ohio Railway used the name Kanawha for their 2-8-4s. In Europe, this wheel arrangement was mostly seen in mainline passenger express locomotives and, in certain countries, in tank locomotives. Overview In the United States of America, the 2-8-4 wheel arrangement was a further development of the enormously successful 2-8-2 Mikado. It resulted from the requirement for a freight locomotive with even greater steam heating capacity. To produce more steam, a solution was to increase the size of the locomotive's firebox, though the 2-8-2 wheel arrangement, with its single axle trailing truck, limited the permissible increased axle loading from a larger firebox. The most practical solution was to add a second trailing axle to spread the increased weight of a larger firebox. The first American 2-8-4s were built for the Boston and Albany Railroad in 1925 by Lima Locomotive Works. The railroad's route across the Berkshire mountains was a substantial test for the new locomotives and, as a result, the name Berkshire was adopted for the locomotive type. In Europe, 2-8-4 tender locomotives were designed mainly for passenger express trains, but they also hauled long distance express freights to increase utilisation. European 2-8-4 tank locomotives were a logical transition from the 2-8-2T locomotive types, allowing larger fireboxes and larger coal bunkers. They were mainly used for busy suburban services in heavily populated suburban areas of big cities, but infrequently also for sparsely populated rural areas or long distance lines. Usage Australia The Western Australian K-class was a class of 2-8-4T steam locomotives of the Western Australian Government Railways (WAGR). Between 1893 and 1898, the WAGR took delivery of 24 of these locomotives from Neilson and Company. They entered service on the Eastern Railway between Midland Junction and Northam. In 1900, during the Second Boer War, the Imperial Military Railways experienced a shortage of locomotives and six more new K class locomotives destined for the WAGR were diverted to South Africa, where they were known as the Western Australians. The South Australian Railways also operated 2-8-4s. Fleet construction commenced in 1930 and by the end of 1943, seventeen locomotives were in service on the gauge system. The design of