South African Class GM 4-8-2+2-8-4

The South African Class GM 4-8-2+2-8-4 of 1938 is a South African steam locomotive from the South African Railways era.

During 1938 and 1939 the South African Railways placed sixteen Class GM Garratt articulated steam locomotives with a 4-8-2+2-8-4 Double Mountain type wheel arrangement in goods train service.^[2][3][4]

Manufacturer

By 1938 the rapidly increasing traffic on the line from Johannesburg via Krugersdorp and Zeerust to Mafeking led to the preparation of designs for a Garratt locomotive that would be equal to two Class 19D locomotives by W.A.J. Day, Chief Mechanical Engineer (CME) of the South African Railways (SAR) from 1936 to 1939. The initial designs of the Class GM were rejected by the Chief Civil Engineer, however, since the weight on the leading and trailing bogies exceeded the acceptable limit for 60 pounds per yard (30 kilograms per metre) rail.^[2][4][5][6]

Class GM's type X-17 water tender

To overcome this, the water capacity of the front water tank was reduced to 1,600 imperial gallons (7,300 litres) while the rear bunker was redesigned to carry no water and with a coal capacity of 10 long tons (10 tonnes). The meagre water supply, which was really only sufficient for shunting purposes, was augmented by semi-permanently coupling a specially built type X-17 auxiliary tank wagon with a 6,810 imperial gallons (31,000 litres) capacity to the locomotive.^[2][4][5][6]

In all other respects the design followed that of the heavy Class GL Garratt. An order for sixteen locomotives was placed with Beyer, Peacock and Company in 1938, while their auxiliary water tank wagons were built in the Pietermaritzburg shops. The locomotives were delivered in 1938 and 1939, erected in the Durban shops and numbered in the range from 2291 to 2306.^[2]

The boilers were of outstanding proportions to enable the locomotives to cope with one particular bank on the Zeerust line that required continuous steaming for 75 minutes. They were superheated, with bar frames, mechanical stokers and Walschaerts valve gear, and since the proportions of the engine units and the wheel diameters were the same as that of the Class 19D, many of their parts were made interchangeable.^[2][3][4]

Service

South African Railways

They were placed in service on the Mafeking line out of Johannesburg that they were designed for. This was a difficult section with numerous 1 in 40 gradients, since from the Reef the elevation drops from 5,700 to 4,600 feet (1,700 to 1,400 metres) within 20 miles (32 kilometres), followed by a rise to over 5,000 feet (1,500 metres) in the next 11 miles (18 kilometres) and then another drop to 3,585 feet (1,093 metres).^[6]

The unusual arrangement of auxiliary water tanks, which had first been used in South Africa with the sole Class KM Kitson-Meyer locomotive in 1904, proved to be very effective and was later repeated with the introduction of the Class GMA and Class GO Garratts.^[2][4][6]

The Class GM remained working on the Mafeking section, initially out of Johannesburg and, after electrification of the West Rand lines, out of Krugersdorp, until they were replaced by diesel traction in 1972. Most of the locomotives were then transferred to work from Pretoria to Pietersburg, where they were employed until they were officially withdrawn from service on 1 August 1973.^[4][5][6]

Three of them were soon placed back in service when a series of accidents in the Eastern Transvaal led to a shortage of Class GMAM Garratts. Numbers 2301, 2303 and 2304 were recalled from retirement, overhauled and despatched to Breyten to fill the power vacuum. They remained in extended service for nearly two years, initially taking part in the mainline workings to Piet Retief and later employed on short pick-up trips to Ermelo and on the Spitskop colliery shunt. They were finally retired at the end of 1974 when the Class GMAM serviceability returned to normal.^[5][6]

Industrial

While the rest were scrapped, the three locomotives that filled the power gap at Breyten were sold to Dunn’s Locomotive Works and were hired out to various coal mines.^[5][6]

• No. 2301 went to Douglas Colliery in November 1975 and was used for two years with the old tender of Class MC1 number 1643.
• No. 2303 was hired to Durnacol, where it worked until circa 1978, coupled to an old Class 1 tender.
• No. 2304 was at first hired to Transvaal Navigation Collieries and was transferred to Tweefontein United Colliery in July 1977, but fell into disuse soon afterwards.

Sides illustrated

The main picture shows Class GM number 2298 at Krugersdorp on 23 April 1970. That and the following pictures serve to illustrate both sides of the locomotive.

• 

  Class GM at Braamfontein depot, circa 1940

• 

  Class GM, circa 1950

See also

• Articulated locomotive numbering and classification
• List of South African locomotive classes
• South African Class GEA 4-8-2+2-8-4
• South African Class GL 4-8-2+2-8-4
• South African Class GMA 4-8-2+2-8-4
• South African Class GO 4-8-2+2-8-4
• South African locomotive history
• The 4-8-2+2-8-4 "Double Mountain"

References

Wikimedia Commons has media related to: South African Class GM (4-8-2+2-8-4)

Locomotives of South Africa Steam Brunel gauge HBEL 0-4-0 HBTB 0-4-0T HBTB 0-4-0WT HBTB 0-4-0ST Broad gauge CGR Aid CGR Blackie CGR 0-4-2 CGR 2-4-0T NRC Durban NRC Natal NRC Perseverance Cape gauge Tank CGR Coffee Pot CGR 040 1873 CGR 040 1874 CGR 060 1876 CGR 060 1902 CGR 260 1900 CGR 260 1902 CGR 1st 040 1875 CGR 1st 440 1875 CGR 1st 040 1876 CGR 1st 260 1876 CGR 2nd 1882 CGR 3rd 1900 CGR RM CSAR C CSAR E CSAR Rack CSAR RM Dbn Congella Dbn Edward Innes Dbn John Milne Dbn Sir Albert HBPE 040 Kowie 060 Kowie 440 M&S 462 NGR Dbn & Pmb NGR I 262 NGR K 040 NGR K 060 NGR K 260 NZASM 10T NZASM 14T NZASM 18T NZASM 19T NZASM 32T NZASM 40T PPR 26T PPR 35T SAR RM SAR 0-4-0ST SAR 040 69 SAR A SAR B SAR C SAR C1 SAR C2 SAR D SAR E SAR F SAR G SAR H SAR H1 SAR H2 SAR J SAR K SWA 2-8-0T Cape gauge Tender CGR 1st 260 1876 BP CGR 1st 260 1876 K CGR 1st 260 1879 CGR 1st 440 1879 CGR 1st 1881 CGR 1st 1891 CGR 2nd 1875 CGR 3rd 1883 CGR 3rd 1884 CGR 3rd 1889 CGR 3rd 1898 CGR 3rd 1901 CGR 3rd 1903 CGR 4th 1880 CGR 4th 1882 CGR 4th 1884 CGR 4th 1897 CGR 5th 1890 CGR 5th 1891 NGR Havelock NGR I 260 Exp-1 Exp-2 Exp-3 Exp-4 Exp-5 Exp-6 SAR S SAR S1 SAR S2 SAR 1 SAR 1A SAR 1B SAR 2 SAR 2C SAR 3 SAR 3A SAR 3B SAR 4 SAR 4A SAR 5 SAR 5A SAR 5B SAR 6 SAR 6A SAR 6B SAR 6C SAR 6D SAR 6E SAR 6F SAR 6G SAR 6H SAR 6J SAR 6K SAR 6L SAR 6Y SAR 6Z SAR 7 SAR 7A SAR 7B SAR 7C SAR 7D SAR 7E SAR 7F SAR 8 SAR 8A SAR 8B SAR 8C SAR 8D SAR 8E SAR 8F SAR 8X SAR 8Y SAR 8Z SAR 9 SAR 10 SAR 10A SAR 10B SAR 10C SAR 10D SAR 11 SAR 12 SAR 12A SAR 12B SAR 13 SAR 14 SAR 14A SAR 14B SAR 14C SAR 15 SAR 15A SAR 15B SAR 15C SAR 15CA SAR 15E SAR 15F SAR 16 SAR 16A SAR 16B SAR 16C SAR 16D SAR 16DA SAR 16E SAR 17 SAR 18 SAR 19 SAR 19A SAR 19B SAR 19C SAR 19D SAR 20 SAR 21 SAR 23 SAR 24 SAR 25 SAR 25NC SAR 26 SWA 2-8-0 Cape gauge Articulated CGR Fairlie CGR Kitson-Meyer SAR FC SAR FD SAR GA SAR GB SAR GC SAR GCA SAR GD SAR GDA SAR GE SAR GEA SAR GF SAR GG SAR GH SAR GK SAR GL SAR GM SAR GMA SAR GO SAR HF SAR KM SAR MA SAR MB SAR MC SAR MC1 SAR MD SAR ME SAR MF SAR MG SAR MH SAR MJ SAR MJ1 SAR U 2ft 6in gauge CCC 1871 CCC Britannia CCC Caledonia CCC Clara CCC Condenser CCC Scotia NCC Pioneer 2ft & 600mm gauges ACR NG-G16A CGR NG 060 CGR NG 462 CGR A CGR C NGR N SAR 040 1899 SAR NG1 SAR NG2 SAR NG3 SAR NG4 SAR NG5 SAR NG6 SAR NG7 SAR NG8 SAR NG9 SAR NG10 SAR NG-G11 SAR NG-G12 SAR NG-G13 SAR NG-G14 SAR NG15 SAR NG-G16 SWA Ha SWA Hb SWA Hc SWA Hd SWA Jung SWA Zwillinge Diesel -electric SAR DS SAR DS1 SAR 31-000 SAR 32-000 SAR 32-200 SAR 33-000 SAR 33-200 SAR 33-400 SAR 34-000 SAR 34-200 SAR 34-400 SAR 34-500 SAR 34-600 SAR 34-800 SAR 34-900 SAR 35-000 SAR 35-200 SAR 35-400 SAR 35-600 SAR 36-000 SAR 36-200 SAR 37-000 SN 39-000 TFR 39-200 TFR 43-000 SAR 91-000 Afro4000 -hydraulic SAR 61-000 Electro-diesel SN 38-000 Electric SAR ES SAR ES1 Exp-AC SAR 1E SAR 2E SAR 3E SAR 4E SAR 5E-S1 SAR 5E-S2 SAR 5E-S3 SAR 5E1-S1 SAR 5E1-S2 SAR 5E1-S3 SAR 5E1-S4 SAR 5E1-S5 SAR 6E SAR 6E1-S1 SAR 6E1-S2 SAR 6E1-S3 SAR 6E1-S4 SAR 6E1-S5 SAR 6E1-S6 SAR 6E1-S7 SAR 6E1-S8 SAR 6E1-S9 SAR 6E1-S10 SAR 6E1-S11 SAR 7E SAR 7E1 SAR 7E2-S1 SAR 7E2-S2 SAR 7E3-S1 SAR 7E3-S2 SN 7E4 SAR 8E SAR 9E-S1 SAR 9E-S2 SAR 10E SAR 10E1-S1 SAR 10E1-S2 SAR 10E2 SAR 11E SAR 12E SN 14E SN 14E1 TFR 15E SN 16E SN 17E SN 18E-S1 TFR 18E-S2 TFR 19E TFR 20E TFR 21E E38 List of South African locomotive classes Rail transport in South Africa