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

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South African Railways Class GMA
Company typeSteam locomotive class
IndustryRailway
Founded1954
Headquarters
South Africa
ProductsGarratt articulated steam locomotives

South African Railways Class GMA 4-8-2+2-8-4 Articulated Steam Locomotive

Between 1954 and 1958, the South African Railways introduced a fleet of 120 Class GMA Garratt articulated steam locomotives, featuring a Double Mountain wheel configuration of 4-8-2+2-8-4. These locomotives were uniquely versatile, designed to be operated either as Class GMA units for branch line service or reconfigured as Class GMAM engines suitable for mainline duties. This class holds the distinction of being the most extensively produced Garratt type worldwide.

Manufacturers

The Class GMA branch line and Class GMAM mainline Garratt locomotives represented a single model adaptable for either branch or mainline duties. This design evolved from the substantial Class GM branch line engine that was first introduced on the South African Railways (SAR) in 1938. Similar to the Class GM, the Class GMA featured a tank-and-tender Garratt configuration, operating with a semi-permanently attached auxiliary water tender to compensate for its limited onboard water supply.[1][2][3]

File:L.C. Grubb.jpg
L.C. Grubb

The locomotive’s design was finalized in 1952 under the leadership of L.C. Grubb, who served as Chief Mechanical Engineer (CME) of the SAR from 1949 until 1954. The initial order for twenty-five units was placed with Henschel and Son in Germany. These machines were constructed in 1953, subsequently delivered and commissioned into service in 1954, bearing numbers from 4051 to 4075. The first series was fitted with Type X-17 water tenders, manufactured at the SAR’s Pietermaritzburg workshops during 1953.[4][5][6][7]

A subsequent batch of thirty-five locomotives arrived in 1956 from Beyer, Peacock and Company (BP). Of these, twenty-three were constructed directly by BP and assigned numbers between 4076 and 4098. The remaining twelve units, numbered from 4099 to 4110, were subcontracted by BP to the North British Locomotive Company (NBL), resulting in works plates displaying both BP and NBL as manufacturers.[4][8][9][10]

File:SAR Class GMAM 4140 (4-8-2+2-8-4) BP.jpg
BP & NBL works plate off no. 4140

The final production run took place in 1958, comprising sixty locomotives. Within this group, thirty were supplied by BP; however, only ten units numbered between 4121 and 4130 were actually built by BP themselves. The other twenty engines—numbered from 4111 to 4120 and from 4131 to 4140—were once again subcontracted to NBL by BP and thus bore dual manufacturer plates indicating both builders. Notably, locomotive number 4140 was the last steam engine constructed by North British. The remaining thirty locomotives of this batch, numbered from 4141 to 4170, were produced by Henschel in Germany.[1][4][5][8][9][10]

Locomotives from both the second and third series were equipped with Type X-20 water tenders, which were fabricated at Pietermaritzburg workshops between the years of 1956 and 1958.[1][6][11]

Characteristics

The Class GMA light rail branch line and the mainline Class GMAM locomotives were essentially identical models, with adjustable water and coal capacities achieved by fitting or removing partitions within the respective tanks and bunkers. This interchangeability made it difficult to distinctly categorize the GMA and GMAM variants, as they were frequently converted between configurations. For instance, around 1962, the fleet comprised 20 Class GMA and 100 Class GMAM units; by 1969, the numbers had shifted to 69 Class GMA and 39 Class GMAM, with two locomotives having been withdrawn due to accident damage. By 1975, the distribution changed again to 25 Class GMA and 93 Class GMAM.

The locomotive featured a contemporary design, including a single-piece cast steel frame equipped with Franklin spring-loaded wedge horns, produced by Commonwealth Steel Castings Corporation in the USA. Similar to the Class 25, it had roller bearing axle boxes on all wheels except for the crank-pins. Cannon boxes were fitted on every axle except for those of the inner Bissel trucks, which utilized outside bearings. Mechanical lubrication was applied throughout the machine, complemented by self-adjusting pivots, a U-shaped foundation ring welded at both inner and outer firebox bottom edges, and an entirely welded firebox. The engine units themselves incorporated Commonwealth cast steel type frames.

The boiler measured 6 feet 11+1⁄2 inches (2,121 millimetres) in internal diameter at the first ring, expanding to 7 feet 1+1⁄4 inches (2,165 millimetres) near the firebox end. It included an inspection manhole positioned atop the boiler behind the dome. Designed with superheating capabilities, the locomotive employed a mechanical stoker and Walschaerts valve gear. It was capable of negotiating curves with a minimum radius of 275 feet (84 metres), requiring no more than 3⁄4 inch (19 millimetres) gauge widening and a superelevation of 4+1⁄2 inches (114 millimetres).

Certain locomotives intended for routes featuring tunnels—such as those on the East London mainline—were initially fitted with steam-operated smoke deflecting cowls above their chimneys. After these cowls were removed, these specific engines could still be recognized by their notably shortened chimneys, designed originally to accommodate the cowls within clearance limits.

Following the approach used on their predecessor, the Class GM, these locomotives stored water exclusively in their front tanks but increased capacity from the Class GM’s 1,600 imperial gallons (7,300 L) to either 1,650 imperial gallons (7,500 L) for Class GMA or 2,100 imperial gallons (9,500 L) for Class GMAM. Similarly, coal was carried solely in rear bunkers with capacity expanded from the Class GM’s 10 long tons (10 t) to either 11 long tons (11 t) for Class GMA or 14 long tons (14 t) for Class GMAM.

File:30 019 389 X-17 (Side A).jpg
Type X-17 water tender
File:Type X-20 tender no. 30 025 052.jpg
Type X-20 water tender no. 4128

As with the earlier Class GM locomotives, Class GMA engines supplemented their onboard water supply by semi-permanently attaching specially designed auxiliary water tenders. The initial set of 25 locomotives utilized Type X-17 tenders—the same as those paired with the Class GM—holding between 6,750[convert: needs unit name] and 6,815[convert: needs unit name] imperial gallons. Subsequent locomotives were coupled with Type X-20 tenders featuring a capacity of approximately 6,790[convert: needs unit name] imperial gallons. These tenders bore numbers matching their respective engines and were painted black with red buffer beams.

Although designed to run on rails rated at 60 pounds per yard (30 kg/m), despite a maximum axle load of 15[convert: needs unit name] long tons seen on the Class GMAM, this was achieved by limiting weight on both leading and trailing bogies to around 22[convert: needs unit name] long tons and balancing coupled wheels so that hammer blow forces remained uniform across all wheels without exceeding one ton per wheel at speeds up to [convert: invalid number].

While SAR specifications mandated a maximum axle load of 15[convert: needs unit name] long tons, throughout its operational life the Class GMAM mainly ran on tracks supporting loads of 18[convert: needs unit name] long tons or more. The imposed constraints on coal bunker size and onboard water tank capacity—restricted respectively to 14[convert: needs unit name] long tons and 2,100[convert: needs unit name] imperial gallons—and the need to haul additional water tenders limited operational flexibility. These factors likely contributed to their limited utility and may have been among the reasons behind SAR's swift transition to diesel traction during the 1960s.

South African Railways

With a total of 120 units produced, this class became the most prolific Garratt type globally. The Class GMA and GMAM locomotives operated extensively on both primary and secondary routes throughout South Africa. Before the electrification era, several were assigned to the Transvaal region, particularly on the Komatipoort line traversing the pass between Waterval Onder and Waterval Boven. Alongside the Class GM, these Garratts also served the route connecting Krugersdorp through Zeerust to Mafeking.

They were temporarily utilized on the coal transport line from Witbank to Germiston until electrification was completed between Witbank and Welgedag. The second and third production groups, ordered starting in 1956, were intended to handle increased traffic volumes—mainly coal—moving from Transvaal to destinations within the Free State and Cape Province. Prior to the introduction of the SAR’s first mainline diesel locomotives, the Class DE-1 (Class 31-000), late in 1958, these Garratts managed block coal trains over a 208-mile (335 km) stretch from Witbank to Kroonstad. It was notable that such a significant order was placed for locomotives with an axle load of 15 long tons on a route constructed for only 21 long tons axle loading.

In Natal, the majority of this class was based at Pietermaritzburg, where they handled most services on two steeply graded branch lines leading to Greytown and Franklin. Additional units operated on the Natal North Coast line between Stanger and Empangeni, while some worked alongside Class GL locomotives on the coal line running from Vryheid to Glencoe.

File:Class GMAM 4079 (4-8-2+2-8-4) ID.JPG

Locomotives assigned to the Cape Western system were housed at Worcester, from which they operated along the former New Cape Central Railway (NCCR) route via Riversdale to Mosselbaai until diesel traction replaced steam. Between 1981 and 1984, several were transferred to the Cape Northern system to serve the Vryburg–Mafeking line, largely supplanting Class 19D locomotives that had previously dominated this corridor. This period marked their final mainline deployment before being replaced by Class 25NC engines in 1984 following track upgrades with heavier rails.

In 1984, most of these locomotives were reassigned to the Cape Midland System. Initially based at Voorbaai, they took over duties from Class GEA units on services running from Mosselbaai to Riversdale and across Montagu Pass to Oudtshoorn. Their operational territory later expanded to include sheds at Sydenham (Port Elizabeth), Rosmead, Klipplaat, and Graaff-Reinet. Consequently, they covered nearly all trains along the route from Port Elizabeth to Rosmead via Klipplaat and traversed Lootsberg Pass departing Graaff-Reinet.

Towards the end of their operational lifespan, some remained allocated within the Eastern Transvaal system. Locomotives from Waterval Boven and Breyten depots continued working the line extending down to Vryheid in Natal.

This class represented the final Garratt type retained in service by South African Railways. By April 1988, all but three units had been withdrawn; these remaining three were retired shortly thereafter.

The last locomotive delivered was number 4140 (builder’s number BP 7855 / NBL 27792), which also holds distinction as the final steam engine constructed by the North British Locomotive Company.

Zimbabwe and Mozambique

Between August 1979 and September 1981, a total of 26 locomotives from this Class were leased to Zimbabwe-Rhodesia. However, they were not all deployed simultaneously; instead, they alternated with Capital Park in Pretoria, which served as their official base when major overhauls in South Africa were required. On the Rhodesia Railways (RR), later renamed the National Railways of Zimbabwe, these engines operated routes extending from Bulawayo through Gwelo, reaching Wankie and further onward to Victoria Falls.

File:Class GMAM no. 4065.jpg
GMAM no. 4065 with raised coal bunker sides at Bulawayo Locoshed, 15 April 1980

A subset of six locomotives was temporarily loaned by RR to the Caminhos de Ferro de Moçambique (CFM) to service the CFM Centro line connecting Beira and Umtali in Zimbabwe.

While operating in Zimbabwe-Rhodesia, these locomotives typically ran chimney first, with the water tank positioned at the rear. Due to the ongoing Rhodesian bush war in 1979, armor plating was installed around the cabs for protection. This armor obscured the original number plates, prompting the practice of stenciling engine numbers on the cab sides for identification. The Class GMAM bore similarities in size and coal capacity to the Rhodesia Railways 20th class 4-8-2+2-8-4 Garratt; however, it consumed coal at a notably high rate and frequently faced fuel shortages that sometimes forced trains to be abandoned en route. To address this issue, RR increased the height of the GMAM’s coal bunker by one foot to enhance its fuel capacity.

The following list details the specific GMAM Garratts hired to Rhodesia/Zimbabwe during this period:

  • 4059: Hired December 1979 – July 1981
  • 4060: Hired August 1979 – September 1981
  • 4064: Hired August 1979 – May 1981
  • 4065: Hired August 1979 – March 1981
  • 4070: Hired August 1980 – February 1981
  • 4071: Hired December 1979 – September 1980
  • 4087: Hired August 1979 – September 1981
  • 4089: Hired August 1979 – October 1981
  • 4090: Hired December 1979 – September 1980
  • 4098: Hired January 1980 – September 1981
  • 4099: Hired December 1979 – March 1981
  • 4102: Hired September 1980 – May 1981
  • 4103: Hired December 1979 – February 1981
  • 4111: Hired February 1980 – February 1981
  • 4112: Hired August 1979 – October 1980
  • 4117: Hired June 1980 – February 1981
  • 4120: Hired August 1979 – October 1980
  • 4121: Hired December 1979 – September 1981
  • 4125: Hired August 1979 – April 1980
  • 4126: Hired December 1979 – January 1980
  • 4129: Hired March 1979 – October 1980
  • 4134: Hired August 1979 – October 1980
  • 4135: Hired August 1979 – February 1981
  • 4137: Hired August 1979 – September 1980
  • 4139: Hired August 1979 – August 1981
  • 4140: Hired December 1979 – August 1981

Industrial Use, Private Acquisition, and Conservation

File:Class GMAM 4136 (4-8-2+2-8-4) REGM R12 ID.JPG
REGM R12 Number plate, formerly SAR no. 4136

A number of locomotives from this class transitioned into industrial roles, with several ultimately preserved following transfer into private hands. The bulk were acquired by the Randfontein Estates Gold Mining Company (REGM). Two units were intended for the Hotham Valley Railway in Western Australia to haul tourist trains using former SAR passenger coaches. However, locomotives 4090 and 4129 never departed South Africa; after remaining at Bloemfontein locomotive depot for two decades, both were dismantled in May 2016. Locomotive 4074 underwent reconstruction after its tenure at REGM, utilizing the boiler cradle from 4126, thus it is catalogued accordingly under Beyer Peacock's numbering and identification system.

  • No. 4059 was designated REGM no. R16, initially named Sarah and later renamed Wendy. It has since been scrapped.
  • No. 4060 became REGM's first no. R15 May, now dismantled.
  • No. 4073 was assigned REGM no. R17 Doria, currently scrapped.
  • No. 4079 served as REGM's second no. R15 May, later renumbered R1. Presently, it is exhibited at Sandstone Estates.
  • No. 4083 was reclassified as REGM R3. Following refurbishment at Dunn's in 1997, it was transported to New Zealand for preservation with Mainline Steam, employing power units from 4088 and operated there twice. Testing revealed a bent front power unit; a replacement from the dismantled 4126 was shipped from Dunn's. Currently, it carries the front engine unit of no. 4126 and the rear unit of no. 4088.
  • No. 4084 became REGM no. R9, later renumbered R10 after July 1983; it was scrapped following a collision in April 1985.
  • No. 4088 held REGM number R2; although sold to Sandstone Estates, it was never delivered and was scrapped onsite at REGM after removal of its power units for use on 4083.
  • No. 4090 was slated for transfer to the Hotham Valley Railway but was scrapped at Bloemfontein Loco in May 2016.
  • No. 4107 carried REGM's first no. R14 Cherrie, now dismantled.
  • No. 4108 went to Tweefontein Colliery and has since been scrapped.
  • No. 4110 was designated REGM no. R6 and is now scrapped.
  • No. 4112 initially went to England still operational for preservation purposes and later became part of the Summerlee Museum of Scottish Industrial Life in Coatbridge, Scotland.
  • No. 4114 served as REGM no. R5 and is currently displayed at Sandstone Estate.
  • No. 4119 was REGM's second no. R14 Cherrie, now scrapped.
  • No. 4123 held REGM number R11 Vivienne; it has since been scrapped.
  • No. 4125 was sold to Dunns, initially leased to Durnacol and subsequently to Tweefontein Colliery as their no. 2 Margret, now scrapped.
  • No. 4126 transferred to Tweefontein Colliery; components including its boiler cradle were later sold to Umgeni Steam Railway. In April 2010, it was donated to Creighton municipality which funded its overhaul after Umgeni Steam Railway declared bankruptcy and could not cover costs—this intervention prevented certain scrapping. As of January 2024, it remains the sole operational GMA/M Cape gauge Garratt in South Africa, running under number 4074 using its power units.
  • No. 4128 became REGM no. R9 Kathy. It was later returned to Transnet for excursion duties and has been stored at Voorbaai since 2005.
  • No. 4129 intended for Hotham Valley Railway; scrapped at Bloemfontein Loco in May 2016.
  • No. 4130 served as REGM no. R8; now scrapped.
  • No. 4133 held REGM's second no. R10 designation; currently scrapped.
  • No. 4135 became REGM's third no. R14 Joan, later renumbered R4 and renamed Barbara. It is presently stored near Pretoria awaiting future deployment by German rail tour operator FarRail.
  • No. 4136 carried REGM number R12 Barbara before being returned to Transnet; it remains stored at Bloemfontein.
  • No. 4168 was sold to Dunns, leased first to Durnacol then Tweefontein Colliery as their no.1; it has since been scrapped.

Preservation

Number Manufacturer/Works THF / Private Lease-lend / Owner Present location Outside South Africa Remarks
4056 Henschel 28685 THF THF Waterval Boven Locomotive Depot
4070 Henschel 28699 THF THF George Transport Museum Fueled by oil
4074 (4126) Henschel 28703 Private Creighton Municipality Creighton In service
4079 BP 7677 Private Sandstone Estate Displayed at Sandstone Estate
4083 BP 7681 Private Mainline Steam Mercer New Zealand
4112 BP 7827 / NBL 27770 Private Summerlee Museum of Scottish Industrial Life Coatbridge Scotland
4114 BP 7829 / NBL 27772 Private Sandstone Estate Displayed at Sandstone Estate
4122 BP 7837 THF THF Voorbaai Locomotive Depot
4128 BP 7843 THF THF Voorbaai Locomotive Depot
4135 BP 7850 / NBL 27787 Private FarRail Hermanstad
4136 BP 7851 / NBL 27788 THF Bloemfontein Locomotive Depot

Works numbers

The table below details the manufacturers, works numbers, and construction years for these locomotives.[4][5][8][9][10]

4076 | BP | 7550 | | 1956 4077 | BP | 7551 | | 1956 4078 | BP | 7552 | | 1956 4079 | BP | 7677 | | 1956 4080 | BP | 7678 | | 1956 4081 | BP | 7679 | | 1956 4082 | BP | 7680 | | 1956 4083 | BP | 7681 | | 1956 4084 | BP | 7750 | | 1956 4085 | BP | 7751 | | 1956 4086 | BP | 7752 | | 1956 4087 | BP | 7753 | | 1956 4088 | BP | 7754 | | 1956 4089 | BP | 7755 | | 1956 4090 | BP | 7756 | | 1956 4091 | BP | 7757 | | 1956 4092 | BP | 7758 | | 1956 4093 | BP | 7759 | | 1956 4094 | BP |7760||1956 4095||BP||7761||1956 4096||BP||7762||1956 4097||BP||7763||1956 4098||BP||7764||1956 4099||BP/NBL||7765||27691||1956 4100||BP/NBL||7766||27692||1956 4101||BP/NBL||7767||27693||1956 4102||BP/NBL||7768||27694||1956 4103||BP/NBL||7769||27695||1956 4104||BP/NBL||7770||27696||1956 4105||BP/NBL||7771||27697||1956 4106||BP/NBL||7772||27698||1956 4107||BP/NBL||7773||27699||1956 4108||BP/NBL||7774||27700||1956 4111 |||BP/NBL 7826 27769 1958 4112 |||BP/NBL 7827 27770 1958 4113 |||BP/NBL 7828 27771 1958 4114 |||BP/NBL 7829 27772 1958 4149 |||Henschel 29608 1958 4150 |||Henschel 29609 1958


Illustration

References

  1. ↑ 1.0 1.1 1.2 Cite error: Invalid <ref> tag; no text was provided for refs named Holland 2
  2. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named Paxton-Bourne
  3. ↑ Soul of A Railway, System 7, Western Transvaal, based in Johannesburg, Part 24: Krugersdorp-Zeerust-Mafeking (Home Signal), Part 1 by Les Pivnic. Caption 29. (Accessed on 5 May 2017)
  4. ↑ 4.0 4.1 4.2 4.3 Cite error: Invalid <ref> tag; no text was provided for refs named Garratt Builders O
  5. ↑ 5.0 5.1 5.2 Henschel-Lieferliste (Henschel & Son works list), compiled by Dietmar Stresow
  6. ↑ 6.0 6.1 South African Railways (1985). Rolling Stock Diagrams. Reference CXG 6/4/2/3. Issued 1 April 1985. SAR Head Office, Johannesburg.
  7. ↑ Transnet (1991). Transnet Index and Diagrams of Goods Vehicles, Part II, Tank Wagons. Reference S/RM(WV) 15/8/5/5. 30 July 1991. Anker Building, Verwoerdburgstad. p. X-17.
  8. ↑ 8.0 8.1 8.2 Cite error: Invalid <ref> tag; no text was provided for refs named Garratt Builders B
  9. ↑ 9.0 9.1 9.2 North British Locomotive Company works list, compiled by Austrian locomotive historian Bernhard Schmeiser
  10. ↑ 10.0 10.1 10.2 North British Locomotive Co. (from J. Lambert)
  11. ↑ Transnet (1991). Transnet Index and Diagrams of Goods Vehicles, Part II, Tank Wagons. Reference S/RM(WV) 15/8/5/5. 30 July 1991. Anker Building, Verwoerdburgstad. p. X-20.

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