DieselisationDieselisation (US: dieselization) is the process of equipping vehicles with a diesel engine or diesel engines. It can involve replacing an internal combustion engine powered by petrol (US: gasoline) fuel with an engine powered by diesel fuel, as occurred on a large scale with trucks, buses, farm tractors, and building construction machinery after World War II. Alternatively it can involve replacing the entire plant or vehicle with one that is diesel-powered; the term commonly describes the generational replacement between the 1930s to 1970s of railway steam locomotives with diesel locomotives, and associated facilities.
4-8-2Under the Whyte notation for the classification of steam locomotives, 4-8-2 represents the wheel arrangement of four leading wheels, eight powered and coupled driving wheels and two trailing wheels. This type of steam locomotive is commonly known as the Mountain type. The Colony of Natal in South Africa and New Zealand were innovators of the 4-8-2 Mountain wheel arrangement. The Natal Government Railways (NGR) placed in service the first tank engines with the 4-8-2 arrangement, and the NGR was also first to modify tender locomotives to use a 4-8-2 wheel arrangement.
4-6-2Under the Whyte notation for the classification of steam locomotives, 4-6-2 represents the wheel arrangement of four leading wheels on two axles, six powered and coupled driving wheels on three axles and two trailing wheels on one axle. The 4-6-2 locomotive became almost globally known as a Pacific type after a New Zealand locomotive that was shipped across the Pacific Ocean. The introduction of the 4-6-2 design in 1901 has been described as "a veritable milestone in locomotive progress".
Steam locomotiveA steam locomotive is a locomotive that provides the force to move itself and other vehicles by means of the expansion of steam. It is fuelled by burning combustible material (usually coal, oil or, rarely, wood) to heat water in the locomotive's boiler to the point where it becomes gaseous and its volume increases 1,700 times. Functionally, it is a steam engine on wheels. In most locomotives, the steam is admitted alternately to each end of its cylinders in which pistons are mechanically connected to the locomotive's main wheels.
