South African Class GF 4-6-2+2-6-4

South African Railways Class GF

Company type	Steam locomotive class
Industry	Rail transport
Founded	1927
Headquarters	South Africa
Products	Articulated steam locomotives (4-6-2+2-6-4 Garratt)

Overview

The South African Railways Class GF 4-6-2+2-6-4 represents an articulated steam locomotive introduced in 1927.

During 1927, the South African Railways commissioned 37 Class GF Garratt locomotives featuring a 4-6-2+2-6-4 Double Pacific wheel configuration. An additional batch of 28 units was supplied by two different manufacturers in 1928.

Manufacturers

Throughout Colonel F.R. Collins' tenure as Chief Mechanical Engineer of the South African Railways (SAR) from 1922 to 1929, articulated locomotives enjoyed significant popularity in South Africa. In fact, the Railway Board at the time mandated that orders for non-articulated engines be placed only under exceptional conditions.

Colonel Collins himself drafted the specifications for the Class GF 4-6-2+2-6-4 Garratt locomotive, leading to an initial procurement of 37 units from Hannoversche Maschinenbau AG (Hanomag) in Germany. These locomotives arrived in December 1927 and were assigned numbers ranging from 2370 to 2406.

Subsequently, a second contract was awarded to Henschel and Son in 1927 for eighteen additional locomotives. Delivered by October 1928, this batch bore numbers between 2407 and 2424.

The final order, placed with Maffei in 1928, comprised ten locomotives. They were received in November of the same year and numbered from 2425 through 2434.

• Gf 2401
  Gf 2401
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  Col F.R. Collins DSO
• Gf
  Gf

Characteristics

Equipped with superheaters, bar frames, piston valves, and utilizing Walschaerts valve gear, these locomotives represented the sole Double Pacific Garratt type deployed by the SAR. Until the introduction of the Class GMA, they constituted the largest Garratt class in SAR operation. Designed for mixed traffic duties, they operated primarily on branch lines and secondary main routes nationwide.

Initially, the Class GF featured inside bearings on their two-wheeled trailing trucks; however, this configuration led to frequent hot-box issues on these axles. After converting to outside bearings, their performance improved significantly. The class combined a respectable speed capability with considerable tractive effort, making them versatile and effective locomotives for various applications.

Cabside number plates

File:Class GF no. 2401 ID.jpg

Since the formation of the SAR in 1910, cabside engine number plates featured the inscription "SOUTH AFRICAN RAILWAYS" exclusively in English. This remained unchanged when the Class GF locomotives were introduced, as evidenced by a Hanomag factory photograph of no. 2370. Following the enactment of the Official Languages of the Union Act No 8 of 1925 on 8 May 1925, bilingual cabside number plates displaying both English and Afrikaans began to be used on locomotives. These initially bore "SOUTH AFRICAN RAILWAYS" at the top and "SUID AFRIKANSE SPOORWEË" at the bottom, as illustrated. During the early years, Afrikaans spelling conventions underwent several revisions. For instance, postage stamps showed "Zuid Afrika" from 1913, changed to "Suidafrika" on airmail stamps in 1925, and later hyphenated as "Suid-Afrika" from 1933 onwards. On cabside plates, the Afrikaans text was subsequently modified to "SUID AFRIKAANSE SPOORWEË," changing "AFRIKANSE" to "AFRIKAANSE," and eventually to the hyphenated form "SUID-AFRIKAANSE SPOORWEË."

South African Railways

The Class GF locomotives operated extensively across Natal, Transvaal, the Orange Free State, and the Eastern Cape regions. In Eastern Transvaal, they were based at Nelspruit to serve branch lines leading to Graskop and Plaston. Alongside the Class GE, some units were assigned to routes departing Johannesburg through Krugersdorp and Zeerust on the Mafeking line. On this line, they were permitted a higher coal capacity of 11 long tons 10 hundredweight (11.7 tonnes), compared with the standard 10 long tons (10.2 tonnes) allowed on lighter rail elsewhere.

The majority of Class GF engines were concentrated in Natal. They played a significant role in local passenger services along the Verulam area and other North Coast routes. Several were stationed at Empangeni to manage sugar cane transport from Mtubatuba, while most were located at Mason's Mill to handle various branch lines extending from Pietermaritzburg. Their duties included running a daily passenger service between Franklin and Kokstad, with other branches primarily seeing their use on freight and mixed trains.

As of June 1964, Greyville still housed nine Class GFs that mainly operated local passenger and pick-up goods services. Apart from four units sold off and two withdrawn following collisions, all Class GF locomotives remained in SAR inventory by 1972, though not all were active. The final unit was retired and scrapped in 1979.

Mozambique

File:Gf 2420.jpg

Gf 2420

Four Class GF locomotives, specifically numbers 2370, 2419, 2420, and 2432, were transferred to the Caminhos de Ferro de Moçambique. Within this railway system, they were reclassified as Series 911 and renumbered consecutively from 911 to 914.

Industrial

Upon retirement from mainline service, several Class GF engines found new roles within the mining sector. The majority were acquired by the Enyati Railway, where some units were later fitted with diesel-powered air brake systems housed in protective cages behind their coal bunkers. This modification was necessary since certain SAR air-braked coal export block trains originated at Enyati. The following locomotives are known to have entered industrial service:

• Numbers 2371, 2377, 2378, 2386, 2387, 2399, 2404, 2415, 2417, 2425, and 2429 were allocated to Enyati Railway under Enyati Collieries.
• Locomotive No. 2433 was assigned to Transvaal Navigation Collieries.
• Another unit was delivered to Tweefontein United Collieries and is believed to have subsequently been transferred to Enyati.

Knuckle couplers

Starting in 1927, the SAR initiated the replacement of the traditional Johnston link-and-pin couplers—used since the Cape Government Railways inception in 1873—with modern AAR knuckle couplers across its Cape Gauge rolling stock. Evidence from period photographs alongside official SAR Locomotive Diagram Books and dimensional drawings by Holland indicates that Class GF locomotives were originally supplied equipped with knuckle couplers. This was also true for other classes introduced in that year, including Class 18, GCA, HF, and U.

Transition era knuckle coupler

The full conversion of the fleet spanned several years; during this period both coupling systems remained visible on various rolling stock well into the late 1950s. To maintain compatibility during the transition, locomotive knuckle couplers featured a horizontal slot and a vertical hole in their knuckles designed to fit a link and pin respectively. This adaptation allowed connection with vehicles still fitted with older Johnston couplers.

Knuckle couplers had been introduced in South Africa over twenty years earlier by the Central South African Railways (CSAR), which adopted Gould knuckle couplers on its Limited Express and Imperial Mail passenger trains in 1904. The Limited Express operated between Pretoria and Johannesburg while the Imperial Mail ran between Pretoria and Cape Town. These early knuckle couplers incorporated split knuckles allowing coupling with existing Johnston link-and-pin systems since CSAR retained these older couplers on all locomotives to ensure compatibility with their goods wagons, older passenger stock, and rolling stock from connecting railways.

Preservation

Among the Class GF Garratt locomotives, three units have been retained for preservation. Their condition as of 2020 is summarized below.

Number	Works number	THF / Private	Leaselend / Owner	Current Location	Status
2380		THF	Umgeni Steam Railway	Masons Mill Locomotive Depot	Dismantled
2401		THF	Transnet Heritage Foundation	Outeniqua Transport Museum	Preserved
2416		THF	Ingwe Municipality	Masons Mill Locomotive Depot	Dismantled

Illustration

• Works photograph of no. 2370, constructed by Hannoversche Maschinenbau AG, the inaugural Class GF with cabside number plates in English only, circa 1927
  Works photograph of no. 2370, constructed by Hannoversche Maschinenbau AG, the inaugural Class GF with cabside number plates in English only, circa 1927
• Locomotive no. 2401 displayed at the Outeniqua Transport Museum, George, dated 15 April 2013
  Locomotive no. 2401 displayed at the Outeniqua Transport Museum, George, dated 15 April 2013
• Class GF unit no. 2401 photographed between Swellendam and Bonnievale, around 2001
  Class GF unit no. 2401 photographed between Swellendam and Bonnievale, around 2001
• No. 2401, also known as Cathy, stationed at Grahamstown depot, circa 1991
  No. 2401, also known as Cathy, stationed at Grahamstown depot, circa 1991
• No. 2401 alongside a Class GMAM on the Union Limited service near Buffeljagsrivier, approximately 2001
  No. 2401 alongside a Class GMAM on the Union Limited service near Buffeljagsrivier, approximately 2001