Michael Stephens’ Cape Government Railways (CGR) 5th Class 4-6-0 locomotives with their lengthened smokeboxes entered service. This had such a profound effect on the boiler’s steaming ability that virtually every locomotive on the CGR and NGR had their smokeboxes extended. Beginning in 1905, after D.A. Hendrie took over from Reid as Locomotive Superintendent, these locomotives were gradually fitted with Belpaire fireboxes with wider firegrates. The flat-topped Belpaire firebox had the advantage of an increased area of the water-line at the hottest part of the boiler, together with increased steam space over the firebox. In order to accomplish this, Hendrie raised the boiler's pitch by and cut away the frame under the firebox to accommodate the wider grates. The wider firebox required that the water tanks also had to be moved out and the opportunity was taken to enlarge the tanks. The cabs were also improved to offer the engine crew better protection, and new brass-capped chimneys replaced the original straight flared chimneys. These modified locomotives were known as the Improved Dübs A. When a locomotive classification system was introduced on the NGR, the Dübs A locomotive family was designated Class D. The unmodified locomotives became the Class D1 while the modified locomotives with Belpaire fireboxes became the Class D2. South African Railways When the Union of South Africa was established on 31 May 1910, the three Colonial government railways (CGR, NGR and Central South African Railways) were united under a single administration to control and administer the railways, ports and harbours of the Union. Although the South African Railways and Harbours came into existence in 1910, the actual classification and renumbering of all the rolling stock of the three constituent railways was only implemented with effect from 1 January 1912. In 1912, these engines were designated Class A and were renumbered in the range from 97 to 196, with the unmodified Class D1 locomotives receiving the numbers in the range from 97 to 186 and the ten, at the time, already reboilered Class D2 locomotives receiving the numbers in the range from 187 to 196. In South African Railways (SAR) service, the Improved Dübs A locomotives became known as the Class A Belpaire. In 1915, to help counter wartime motive power shortages brought about by the diminished ability to order new locomotives from European builders due to hostilities, another two Class A locomotives were built from spare parts by the