The South African Railways Class 23 4-8-2 was a class of South African steam locomotives.
In 1938 and 1939, the South African Railways placed 136 Class 23 steam locomotives in service. The Class 23 was the last and the largest 4-8-2 Mountain type locomotive to be designed by the South African Railways.Espitalier, T.J.; Day, W.A.J. (1947). The Locomotive in South Africa - A Brief History of Railway Development. Chapter VII - South African Railways (Continued). South African Railways and Harbours Magazine, January 1947. pp. 29-31.
Manufacturers The Class 23 4-8-2 Mountain type steam locomotive was designed by W.A.J. Day, Chief Mechanical Engineer (CME) of the South African Railways (SAR) from 1936 to 1939. It was intended as a general utility locomotive, capable of operating on rail, and was built in two batches by Berliner Maschinenbau and Henschel and Son in Germany. The original order in 1938 was for twenty locomotives, of which Berliner built seven, numbered in the range from 2552 to 2558, and Henschel thirteen, numbered in the range from 2559 to 2571.Henschel & Son works list, compiled by Dietmar StresowSouth African Railways & Harbours/Suid Afrikaanse Spoorweë en Hawens (15 Aug 1941). Locomotive Diagram Book/Lokomotiefdiagramboek, 3'6" Gauge/Spoorwydte. SAR/SAS Mechanical Department/Werktuigkundige Dept. Drawing Office/Tekenkantoor, Pretoria. pp. VIII, 46.South African Railways & Harbours/Suid Afrikaanse Spoorweë en Hawens (15 Aug 1941). Locomotive Diagram Book/Lokomotiefdiagramboek, 2'0" & 3'6" Gauge/Spoorwydte, Steam Locomotives/Stoomlokomotiewe. SAR/SAS Mechanical Department/Werktuigkundige Dept. Drawing Office/Tekenkantoor, Pretoria. pp. VIII, 6a-7a, 29, 46.
At the time, the urgency brought about by the rapidly deteriorating political climate in Europe led to a further 116 locomotives being ordered even before the first batch could be delivered and tested, contrary to usual SAR practice. Ordering this quantity of a new class of engine before any had been tried out constituted a record for the SAR. Of this second batch, Henschel built 85, numbered in the range from 3201 to 3285, and Berliner 31, numbered in the range from 3286 to 3316. The last locomotive of this second order was delivered in August 1939, just one month before the outbreak of the Second World War.
Berliner-built locomotive no. 3301 received an out-of-sequence works number, Berliner no. 10816 instead of no. 11000, since works number 11000 was reserved for the new Class 01.10 4-6-2 Pacific type locomotive for the German State Railways.
Characteristics In general appearance and power, the Class 23 locomotive is very similar to the Classes 15E and 15F. As originally designed, the locomotive would have had coupled wheels which would have required a newly designed boiler to accommodate the extra length brought about by the long coupled wheelbase. The increasing political turmoil in Europe and the resulting urgency, however, prohibited time being spent on designing a new boiler. As a result, the existing Watson Standard no. 3B boiler was incorporated in the design with an extra long smokebox which was extended by to partially compensate for the shorter boiler. This boiler was one of the range of standard type boilers which was designed by Day's predecessor as CME, A.G. Watson, as part of the latter's standardisation policy. To maintain approximately the same tractive effort as the Class 15E, the boiler pressure was raised to , at the time the highest yet used on the SAR since the SAR loading gauge did not permit horizontal cylinders of greater bore diameter than with normal cylinder spacing.
The locomotives were delivered without smoke deflectors, but after the war they were fitted with standard elephant ear smoke deflectors based upon the Deutsche Reichsbahn design.Soul of A Railway, System 7, Western Transvaal, based in Johannesburg, Part 1. Johannesburg between the Home Signals, Part 1. Captions 21-24, 26-27. (Accessed on 20 March 2017)
The inner firebox was of steel and was fitted with five diameter arch tubes, which supported the brick arch. The rocking grate, with two drop-grates, was actuated by a steam shaker. As was the practice with Watson Standard boilers, the hopper type ashpan was secured to the main frames instead of to the boiler foundation ring, with a air gap all round. Drench pipes were fitted to facilitate cleaning and the bottom of the ashpan was fitted with a hand-operated sliding door.
To enable them to negotiate radius curves, the leading coupled wheels were given a total side-play in their horn blocks, while the tyre flanges of the intermediate coupled wheels were of reduced thickness and the leading coupling rods were provided with spherical bearings at the knuckle joints and crank pins. In addition, largely also as a result of the decision to use the shorter Watson Standard boiler, it was decided to reduce the coupled wheel diameter from the originally intended to , which shortened the coupled wheelbase and would further ease passage on sharp curves.
Tender Since these locomotives were intended for working in the Karoo where good quality water is a scarce resource, they were equipped with very large Type EW tenders which rode on six-wheeled bogies to enable longer runs to be undertaken between watering stops or to skip bad watering places. They were the largest tenders to have been used in South Africa up to that time and as originally designed, would have had a water capacity of and a coal capacity of . Owing to axle load restrictions, however, it was necessary to reduce the water capacity to . The first batch of twenty locomotives were delivered with such tenders.
The second batch of 116 locomotives were delivered with a modification to the tender's underframe. To improve the weight distribution, both tender pivot centres were relocated towards the rear. This enabled the water capacity to be increased to on these 116 tenders. While the locomotive-and-tender's length over couplers was not affected, the total wheelbase of the second batch was longer since the distance between the engine's trailing wheel and the first tender wheel was increased from to .
Four vacuum cylinders operated clasp brakes on all tender wheels and a hand brake was included. Since experience showed that a firegrate of cannot be served effectively under all conditions by manual stoking, particularly on long runs, a type H.T-1 mechanical stoker was fitted, supplied by the Standard Stoker Company of America. The mechanical stoker engine was mounted on the tender.
Streamlining During the 1930s, the streamlining of locomotives was fashionable in Europe and the United States of America. It was proposed to adopt streamlining on some of the Class 23 locomotives which were intended for the Cape mainline and the manufacturers were requested to submit estimates to that effect. Since streamlining would increase the cost by £500 per locomotive and increase the weight by approximately , the idea was abandoned, especially in light of the negligible performance benefit of streamlining at the official maximum goods train speeds on Cape gauge and the reduced accessibility of working parts on a streamlined locomotive.
Locomotive naming Although the naming of locomotives in South Africa dates back to the Cape Town Railway and Dock Company's 0-4-2 locomotives of 20 March 1860 and the Natal Railway's 0-4-0WT Natal of 13 May 1860, it was rarely done. In 1945, the Minister of Transport at the time, the Honourable F. C. Sturrock MP, instructed that a number of Classes 15F and 23 engines should be named after various South African cities and towns and fitted with suitable nameplates in both official languages. The decorative plates were fitted to the sides of the smokebox or to the elephant ear smoke deflectors of engines which were so equipped. Thirteen Class 23 locomotives were named.Espitalier, T.J.; Day, W.A.J. (1947). The Locomotive in South Africa - A Brief History of Railway Development. Chapter VII - South African Railways (Continued). South African Railways and Harbours Magazine, February 1947. p. 131.
No. 3273 - City of Cape Town No. 3277 - City of Pietermaritzburg No. 3278 - Newcastle No. 3279 - Worcester No. 3280 - Oudtshoorn No. 3289 - City of East London No. 3303 - City of Grahamstown No. 3311 - City of Kimberley No. 3312 - Upington No. 3313 - City of Port Elizabeth No. 3314 - Uitenhage No. 3315 - City of Durban No. 3316 - Ladysmith
In later years, some of these names migrated to other engines and classes, several eventually ending up on Class 25NC locomotives. Other names were also added later and, for example, by 1969 no. 3229 bore the name Springs.Soul of A Railway, System 5, Part 1: Bloemfontein. Captions 1, 10. (Accessed on 1 March 2017)
Service The new class soon formed the bulk of the motive power on the lines from Touws River to Beaufort West and from De Aar to Welverdiend via Kimberley and Klerksdorp.
When new, a few Class 23s were briefly allocated to Braamfontein to haul the Union Limited and other Cape express passenger trains from Johannesburg, and the Class 16DA and Class 16E were transferred to Bloemfontein. Since the electric turntable at Braamfontein could not accommodate the locomotive and its long Type EW tender, engines coming in from Klerksdorp had to detach at Johannesburg station and run light to India Junction near Germiston to be turned on the triangular junction. The Braamfontein Class 23s were therefore soon transferred to the Cape Northern System and Braamfontein was provided with Class 15Fs that could fit onto its turntable.Soul of A Railway, System 7, Western Transvaal, based in Johannesburg, Part 22: Braamfontein by Les Pivnic: Braamfontein Yard, Loco, ERS and Old Kazerne Goods Yard, Part 1. Introduction, Caption 23. (Accessed on 4 May 2017)
Upon the arrival of the new Classes 25 and 25NC in 1953, the Class 23 was transferred to Bloemfontein to work south from there to Noupoort and Burgersdorp. Occasionally they worked north to Kroonstad and west across to Kimberley, but the Class 15F generally did most of that work.
When ore traffic from Postmasburg to Durban began to increase in the late 1950s, caboose-working was instituted c. 1959. Block loads of manganese ore were worked by steam over the route from Postmasburg via Kimberley and Bloemfontein to Kroonstad and four block loads were dispatched from Postmasburg to Maydon Wharf in Durban every 24 hours, seven days per week. Four crews on a pair of Class 23 locomotives with a caboose attached for crew accommodation worked in 21-day cycles out of Bloemfontein. The crews were supposed to work eight hours on and eight hours off, but by agreement they usually worked twelve-hour shifts instead.