4-6-0 - Usage - South Africa - Cape Gauge

Cape Gauge

Between 1878 and 1884 the Cape Government Railways (CGR) placed ninety-two Cape 4th Class 4-6-0T+T tank-and-tender locomotives in service, designed by Michael Stephens, Locomotive Superintendent of the Cape Western system at the time, and built in five batches by Robert Stephenson and Company and Neilson and Company. They were side-tank locomotives, delivered with six-wheel tenders that were often removed while working on the shunt. All of them were built with Joy valve gear, but after 1896 many were converted to Stephenson valve gear and had their side-tanks removed at the same time. When thirty-two surviving 4th Class locomotives came into South African Railways (SAR) stock in 1912, they were considered obsolete and designated Class O4. They were withdrawn by 1932.

Between 1879 and 1885 the Natal Government Railways (NGR) placed thirty-seven 4-6-0T tank locomotives in service. Eighteen were built by Kitson and Company and nineteen by Stephenson. They were known on the NGR as the Class K&S, after their builders. When the SAR was established in 1912, the fifteen unmodified survivors were designated Class C. The last one was withdrawn from service in 1940.

Four 4-6-0T+T tank-and-tender locomotives of the CGR’s Experimental 4th Class were supplied by Neilson in 1884, built to the 1882 design of J.D. Tilney, Locomotive Superintendent of the Cape Eastern system at the time, to be able to use low-grade local coal. They had Joy valve gear and unusual six-wheeled tenders, with the leading axle mounted in a rigid frame and the other two axles mounted in a bogie. All four survived until 1912 and were also designated SAR Class O4 as obsolete locomotives.

In 1890 and 1891 fifty Cape 5th Class locomotives were delivered to the CGR from Dübs and Company. An improved version of the Cape 4th Class, they were considered to be the first really efficient all-round six-coupled locomotives in the Colony. Eighteen of them were sold to the Oranje-Vrijstaat Gouwermentspoorwegen (OVGS) in 1897 and one to the New Cape Central Railway (NCCR) in 1906. The OVGS locomotives ended up on Central South African Railways (CSAR) stock after the Second Boer War, and five of them were reboilered with Belpaire fireboxes and Drummond cross-water tubes by the CSAR. Thirty-six of these locomotives in their original form and the five reboilered ones passed into SAR stock in 1912 and were designated Class O5 as obsolete locomotives. They went on to become the last obsolete engines operating on the SAR, only being withdrawn by 1953.

The Cape 6th Class passenger locomotive was designed at the Salt River works of the CGR, according to the specifications of Michael Stephens, then Chief Locomotive Superintendent of the CGR, and under the supervision of H.M. Beatty, then Locomotive Superintendent of the Cape Western system. It was to become one of the most useful classes to see service in South Africa. In 1912, when they came into SAR stock, the 6th Class 4-6-0 family was reclassified into twelve separate classes.

• In 1893 and 1894 the CGR placed forty 6th Class locomotives in service, built by Dübs. Ten of them, sold to the OVGS in 1897, eventually became the Class 6-L1 on the CSAR. In 1912 all forty were assimilated into the SAR and retained their Class 6 classification. (Also see Sudan)
• In 1896 and 1897 the CGR acquired a second batch of fifty, built by Dübs and Sharp, Stewart and Company. These locomotives differed from the previous order in having slightly larger boilers with an increased heating surface and higher coal capacity tenders. In 1907 one was sold to the Benguela Railway in Angola. The remaining forty-nine locomotives were designated Class 6A on the SAR in 1912. (Also see Angola - Cape gauge and Sudan)
• Between 1896 and 1898 the OVGS placed twenty-four new Cape Class 6 locomotives in service, built by Dübs, Neilson and Sharp, Stewart. During the Second Boer War these locomotives were taken over by the Imperial Military Railways (IMR) and after the war they became the CSAR Class 6-L2. All but one were assimilated into the SAR in 1912 and were designated Class 6C. (Also see Sudan)
• In 1897 and 1898 the CGR placed a third batch of fifty-five in service, built by Dübs, Neilson and Company and Neilson, Reid and Company. They were virtually identical to the previous fifty, except that they had bogie-wheeled tenders. In 1907 four were sold to the Benguela Railway in Angola. The remaining fifty-one locomotives were designated Class 6B in 1912. (Also see Angola – Cape gauge and Sudan)
• In 1898 a fourth batch of thirty-three were placed in service by the CGR, built by Neilson, Reid. These represented a further advance on earlier 6th Class locomotives, with a greater heating surface and a larger grate area. In 1912 they were classified as Class 6D on the SAR. (Also see Sudan)
• Also in 1898, the OVGS ordered its final six new Cape 6th Class locomotives from Sharp, Stewart. These were delivered with larger cabs than their predecessors and with bogie-wheeled tenders. They were also taken over by the IMR and, after the war, came into the CSAR as Class 6-L3. In 1912 they became Class 6E on the SAR.
• In 1900 two redesigned 6th Class locomotives entered service on the CGR, built by Sharp, Stewart. They had bar frames, larger cabs and bogie-wheeled tenders, and their larger heating surfaces and grate areas allowed a higher boiler pressure rating of 180 pounds per square inch (1,240 kilopascals). In visual appearance they differed from all previous 6th Class locomotives by having higher running boards without driving wheel fairings. In 1912 they were classified as Class 6F on the SAR.
• In 1901 eight 6th Class locomotives entered service, redesigned and built by the Schenectady Locomotive Works to the specifications of the CGR. Also built on bar frames like the previous two and similar in appearance, they were larger, with larger boilers and 17+1⁄₂ inches (445 millimetres) diameter cylinders compared to the 17 inches (432 millimetres) of all earlier 6th Class locomotives. In 1912 they became Class 6G on the SAR.
• Also in 1901, a batch of twenty-one entered service on the CGR, built by Neilson, Reid to the older plate frame design, but with a larger cab. These also reverted to the 17 inches (432 millimetres) diameter cylinders of the previous British built locomotives, with the lower running boards with driving wheel fairings. One of them was experimental, being equipped with Drummond cross-water tubes in the firebox. However, since the tubes were inclined to leak and were difficult to maintain, they were soon removed. In 1912 these locomotives became the Class 6H on the SAR.
• Ten bar framed locomotives were placed in service, also in 1901, designed and built by the Baldwin Locomotive Works to the specifications of the CGR. They were larger than any of the previous 6th Class locomotives, with larger boilers, large cabs, cylinders of 17+1⁄₂ inches (445 millimetres) bore, bar frames, stovepipe chimneys, large domes and high running boards without driving wheel fairings. In 1912 they became Class 6K on the SAR.
• In 1902 fourteen bar framed 6th Class locomotives entered service on the CGR, built by Neilson, Reid. They were practically identical to the two bar framed locomotives built by Sharp, Stewart in 1900, with high running boards without driving wheel fairings. In 1912 they were reclassified to Class 6J on the SAR.
• In 1904 the CGR placed its last two 6th Class bar framed locomotives in service, built by the North British Locomotive Company (NBL). They were experimental and were the first South African locomotives to have piston valves and superheaters. The pistons, with a diameter of 18+1⁄₂ inches (470 millimetres), were the largest yet used on the 6th Class. The Schmidt superheater was of the smokebox type, but the arrangement was extremely complicated and not very successful. In 1912 they became the Class 6L on the SAR and in 1915, when they were reboilered, the superheaters were removed to convert them to saturated steam locomotives. At the same time the piston-valve cylinders were replaced with smaller slide-valve cylinders of 17+1⁄₂ inches (445 millimetres) bore.