The South African Railways Class A 4-8-2T of 1888 was a steam locomotive from the pre-Union era in the Colony of Natal. In 1888, the Natal Government Railways placed the first five of its eventual one hundred Class D steam locomotives in service. The last was delivered in 1899. They were the first locomotives in the world to be built with a wheel arrangement, later to become known as the Mountain type. In 1912, when these locomotives were assimilated into the South African Railways, they were renumbered and designated Class A. In 1915, another two Class A locomotives were built from spare parts. Manufacturers The Natal Government Railways (NGR) Class D tank locomotive was designed by William Milne, the Locomotive Superintendent of the NGR from 1877 to 1896, and was built by Dübs and Company. The first 46 locomotives, with an operating boiler pressure of and numbered in the range from 49 to 94, were placed in service during Milne's term. They proved to be such good engines that, when G.W. Reid took over as Locomotive Superintendent in 1896, he continued to place further orders for another 58, numbered in the range from 91 to 148, but with the boiler pressure increased to . These 100 locomotives, initially known on the NGR as the Dübs A, were delivered in ten batches by Dübs between 1888 and 1899. As far as is known, the Dübs A locomotives were the first in the world to be designed and built with a wheel arrangement, later to become known as the Mountain type. Modifications The performance in service of the Dübs A was gradually improved by various modifications. New boilers were fitted as and when the originals needed replacement, with a working pressure of instead of the as-delivered of the first few batches. This increased their tractive effort at 75% boiler pressure from to . The coal bunkers were also enlarged and the connecting rod big-ends were changed to the marine type to increase ground clearance. Another modification was an extended smokebox on most locomotives, such as on NGR no. 87 depicted below. In the 1890s, some improvements to smokebox design took place. Extending the smokebox forward increased its volume. The increased amount of exhaust gases present in the smokebox had the effect of stabilising and improving the draught. The date of this improvement can be pinned to 1891 when the second batch of