Under the Whyte notation for the classification of steam locomotives by wheel arrangement, is an articulated locomotive using a pair of power units back to back, with the boiler and cab suspended between them. The 2-6-2 wheel arrangement has a single pair of leading wheels in a leading truck, followed by three coupled pairs of driving wheels and a pair of trailing wheels in a trailing truck. This wheel arrangement could be called a Double Prairie, as all locomotives of this type are effectively two 2-6-2's that always run together.
Overview The wheel arrangement was used on Garratt, Modified Fairlie and Union Garratt locomotives.
Garratt locomotives The was the second most numerous Garratt wheel arrangement to be built, with altogether 238 examples constructed by Beyer, Peacock & Company (BP) and its licensees. Most of them were built to , and the or narrow gauges. None were built to the , but several were built to and gauges.
The first examples of the type were two L class Garratts built for the Tasmanian Government Railways in 1912. This wheel arrangement also included the final Garratts to be built by BP, seven South African Class NG G16 locomotives in 1958.
+2-6-2+2-6-2 Garratt production list – All manufacturers Gauge Railway Class Works no. Units Year BuilderSouth African RailwaysNG G166919-692681939Beyer, PeacockSouth African RailwaysNG G167426-743271951Beyer, PeacockSouth African RailwaysNG G167862-786871958Beyer, PeacockSouth African RailwaysNG G122506-250721927Société Franco-Belge, BelgiumSouth African RailwaysNG G141074711930HanomagSouth African RailwaysNG G1310549-1055131927HanomagSouth African RailwaysNG G1310598-1059921928HanomagSouth African RailwaysNG G1310629-1063571928HanomagSouth African RailwaysNG G163894-390181967-68Hunslet-TaylorSouth African RailwaysNG G163265-326841936John CockerillNepal Government Railway673611932Beyer, PeacockNepal Government Railway724311947Beyer, PeacockSierra Leone Government Railway6297-629931926Beyer, PeacockSierra Leone Government Railway6497-649821928Beyer, PeacockSierra Leone Government Railway6578-657921929Beyer, PeacockSierra Leone Government Railway7045-704841942Beyer, PeacockSierra Leone Government Railway7049-705021943Beyer, PeacockGreat Western of Brazil1024-102521929Armstrong WhitworthLa Robla Railway, Spain421-42221931Babcock & Wilcox, SpainAssam Bengal Railway, IndiaT6385-638951927Beyer, PeacockTransandine Railway, ArgentinaE126543-654641930Beyer, PeacockMinera de Sierra Minera, Spain189-19021930Euskalduna, SpainLa Robla Railway, Spain10646-1064721929HanomagC.G. de F. Catalanes, Spain1960-196341922St Leonard, BelgiumC.G. de F. Catalanes, Spain2035-203841925St Leonard, BelgiumSouth African RailwaysGB594211921Beyer, PeacockNatal Navigation Collieries, South Africa620611925Beyer, PeacockSouth African RailwaysGG623211925Beyer, PeacockDundee Coal & Coke, South Africa635311927Beyer, PeacockTrans Zambezia, Moçambique/NyasalandE638011930Beyer, PeacockConsolidated Main Reef Mine, South Africa678011935Beyer, PeacockTasmanian Government RailwaysL5525-552621912Beyer, PeacockNew Cape Central Railway, South AfricaG6135-613621923Beyer, PeacockTrans Zambezia, Moçambique/NyasalandE6178-617921924Beyer, PeacockSouth African RailwaysGB6181-618661924Beyer, PeacockSouth African RailwaysGC6187-619261924Beyer, PeacockSouth African RailwaysGD6263-626641925Beyer, PeacockRhodesia Railways136269-6280121926Beyer, PeacockSouth African RailwaysGD6281-628771925Beyer, PeacockSouth African RailwaysGD6288-629031926Beyer, PeacockRhodesia Railways146510-651561929Beyer, PeacockGuayaquil & Quito Railway, Ecuador6527-652931929Beyer, PeacockRiotinto Railway, Spain6560-656121928Beyer, PeacockRhodesia Railways146616-6625101930Beyer, PeacockRhodesia Railways14A7581-7592121952Beyer, PeacockRhodesia Railways14A7599-760461953Beyer, PeacockSouth African RailwaysGCA1043-1068261928KruppSouth African RailwaysGCA970-982131927KruppSouth African RailwaysGDA3115-311951929Linke-HofmannNorth Western Railway, IndiaGAS620311925Beyer, PeacockCeylon Government RailwayC1641011927Beyer, PeacockSão Paulo Railway, BrazilR16367-637261927Beyer, PeacockCeylon Government RailwayC1A7160-716781945Beyer, Peacock
Modified Fairlie locomotives The Modified Fairlie was first introduced in South Africa, when the South African Railways (SAR) experimented with a modified type of Fairlie locomotive in order to compare the concept to that of the Garratt locomotive in terms of actual performance and maintenance requirements. In essence, the Modified Fairlie was an adaptation of the Kitson-Meyer concept. It was similar in appearance to a Garratt, but with the boiler, cab, coal and water bunkers all mounted on a single rigid frame which pivoted on the engine units, with the pivot centers located approximately at the centre of the rigid wheelbase of each engine unit. In the Garratt design, by comparison, the coal and water bunkers are mounted directly on the engine units and swivel with them, while the boiler, firebox and cab are mounted on a rigid frame which is suspended between the two engine units.The Fairlie locomotive
Union Garratt locomotives The Union Garratt was a hybrid locomotive, part Garratt and part Modified Fairlie, designed and built for the SAR by Maffei in Munich, Germany. The front end of the locomotive was of a typical Garratt arrangement, with a water tank mounted on the front engine unit’s frame, while the rear end was constructed in the Modified Fairlie fashion, with the coal bunker mounted on a rigid extension of the locomotive’s main frame and with the pivoting rear engine unit positioned beneath the coal bunker.
Usage
Sierra Leone
The Sierra Leone Government Railway acquired altogether 27 gauge 2-6-2+2-6-2 Garratt locomotives from BP between 1926 and 1956. Seven were delivered in 1926, 1928 and 1929. Six more followed in 1942 and 1943 and fourteen more in 1955 and 1956.
Another two were delivered to the Sierra Leone Development Corporation in 1937, also from BP.
South Africa The largest user of the type was the South African Railways (SAR) who operated 132 locomotives of this wheel arrangement, spread over fifteen classes. Of these, ten classes were Cape gauge (83 locomotives) and five classes were narrow gauge (49 locomotives). Two of the narrow gauge locomotives were later rebuilt to improve coal combustion and reclassified.
Cape gauge The 2-6-2+2-6-2 locomotives of the SAR entered service between 1921 and 1929.
In 1921, a single experimental Class GB Garratt entered service, followed by six more in 1924, designed and built by BP. They were superheated, with Belpaire fireboxes, plate frames and Walschaerts valve gear. In 1923, the New Cape Central Railway (NCCR) placed two Garratts in service, built by BP in 1922 to the design of the Class GB. They were also superheated, with plate frames and Walschaerts valve gear, but heavier and with larger cylinders. In 1925, when the NCCR was amalgamated into the SAR, the two Garratts were designated Class GK. In 1924, a single experimental Class FC Modified Fairlie entered service, designed and built by North British Locomotive Company (NBL). It had Walschaerts valve gear, a plate frame and was superheated.North British Locomotive Company works list, compiled by Austrian locomotive historian Bernhard Schmeiser In 1924 and 1925, six Class GC Garratts entered branchline service. They were built by BP in 1924 and were superheated, with Belpaire fireboxes, plate frames and Walschaerts valve gear.South African Railways and Harbours Locomotive Diagram Book, 2’0” & 3’6” Gauge Steam Locomotives, 15 August 1941, as amended
In 1925, a single Class GG Garratt entered service. It was a development of the Class GB with large driving wheels for fast passenger service on mainline duties. Built by BP, it was superheated, with a plate frame, a Belpaire firebox and Walschaerts valve gear. The Class GG was the only Garratt on the SAR to be intended primarily for passenger working. In 1925 and 1926, fourteen Class GD Garratts entered branchline service. Marginally larger and more powerful than their predecessor Class GC and with a higher axle loading, they were built by BP. They were superheated and had plate frames, Belpaire fireboxes and Walschaerts valve gear. In 1926, four Class FD Modified Fairlies entered service, designed and built by NBL in 1925. They had Walschaerts valve gear, plate frames and were superheated.
In 1927, ten Class U Union Garratt locomotives were placed in service. The locomotives, designed and built by Maffei, were superheated and had Walschaerts valve gear and bar frames. In 1927 and 1928, 39 Class GCA Garratts entered branchline service. They were built by Friedrich Krupp of Essen in Germany to the same specifications as the Class GC, but with bar frames, round-topped fireboxes and with water tanks and built-up coal bunkers of a different shape. Like the Class GC, they were superheated and had Walschaerts valve gear. In 1929, five Class GDA Garratts entered branchline service. They were built by Linke-Hofmann Werke in Breslau, Germany, to the same specifications as the Class GD, also superheated and with Walschaerts valve gear, but with bar frames, differently shaped coal and water bunkers and round-topped fireboxes.
Narrow gauge The South African narrow gauge 2-6-2+2-6-2 locomotives entered service between 1927 and 1968. Two were rebuilt in 1989 and 1990 and reclassified.
In 1927, two Class NG G12 Garratts entered service, the smallest Garratts to see service in South Africa. Ordered from BP in 1927, their construction was sub-contracted to Belgian locomotive builders Société Franco-Belge. They were superheated, with outside plate frames, Walschaerts valve gear and round-topped fireboxes.South African Railways and Harbours Narrow Gauge Locomotive Diagram Book, 2’0” Gauge, S.A.R. Mechanical Dept. Drawing Office, Pretoria, 28 November 1932 In 1927 and 1928, twelve Class NG G13 Garratts entered service on the Langkloof and Harding narrow gauge lines. Designed and built by Hannoversche Maschinenbau AG (Hanomag) in consultation with the SAR, the type was to become the standard narrow gauge Garratt in South Africa for the next forty years. They were superheated, with outside bar frames and round-topped fireboxes, and with an extremely compact arrangement of Walschaerts valve gear. The leading wheels were arranged as conventional pony trucks, while the inner trailing wheels were built to the Gölsdorf system which allowed the axle some lateral movement. In 1931, a single light Class NG G14 Garratt entered service. Built by Hanomag in 1930, it was similar to but slightly larger than the , also superheated but with larger bore cylinders, an outside bar frame and a round-topped firebox.
Between 1937 and 1968, 34 Class NG G16 Garratts were placed in service, spread over five orders from three manufacturers. It was almost identical to the Class NG G13, but with all leading and trailing wheels fitted with roller bearing axle boxes and arranged as pony trucks. Société Anonyme John Cockerill of Belgium delivered four in 1937. Another 22 were built by BP in 1939, 1951 and 1958, the last seven being the last steam locomotives to be built by BP. The final eight locomotives in 1968 were the last new steam locomotives to be ordered by the SAR and were built by Hunslet-Taylor in Germiston, Transvaal. In 1989 and 1990, two Class NG G16 Garratts were rebuilt by the Alfred County Railway to incorporate a gas producing combustion system (GPCS) and were reclassified to Class NG G16A. The rebuilding was done by mechanical engineer Phil Girdlestone, using technology similar to that used by mechanical engineer David Wardale in the creation of the Class 26 Red Devil in 1980.Information supplied by Phil Girdlestone
Southern Rhodesia