2-8-2+2-8-2

Locomotive wheel arrangement 2-8-2+2-8-2 (Double Mikado) WheelArrangement 2-8-2+2-8-2.svg Diagram of one small leading wheel, four large driving wheels joined by a coupling rod, two small trailing wheels, four large driving wheels joined by a coupling rod, and one small leading wheel Class GE no. 2274.jpg SAR Class GE, c. 1966 1D1+1D1, 1'D1'+1'D1' 141+141 46+46 4/6+4/6, 8/12 from 1920s 1-4-1+1-4-1 1924 South Africa SAR Class GE South African Railways Beyer, Peacock & Company Beyer, Peacock & Company Under the Whyte notation for the classification of steam locomotives by wheel arrangement, a 2-8-2+2-8-2 is an articulated locomotive using a pair of 2-8-2 power units back to back, with the boiler and cab suspended between them. The 2-8-2 wheel arrangement has a single pair of leading wheels in a leading truck, followed by four coupled pairs of driving wheels and a pair of trailing wheels in a trailing truck. Since the 2-8-2 type was known as Mikado, the corresponding Garratt and Modified Fairlie types were usually known as Double Mikado. Overview The 2-8-2+2-8-2 wheel arrangement was used by Garratt and Modified Fairlie locomotives. Garratt locomotives The Double Mikado was the fourth most common Garratt type, with 144 examples constructed, 114 built by Garratt patent owner Beyer, Peacock & Company and 30 built by others under license. Only 10, six for Chile and four for Peru, were built to 4ft8.5in on on. Ninety were built to Cape on for a number of different African railways. For Spain, sixteen were built to 1672mm on gauge. +2-8-2+2-8-2 Garratt production list – All manufacturers GaugeRailwayClassWorks no.UnitsYearBuilder1000 1000 mm 1 onC.F. Franco Ethiopien & Libya1371-137661939Ansaldo, Italy1000 1000 mm 1 onWar Department, India/Burma7122-7135141944Beyer, Peacock & Company1000 1000 mm 1 onRoyal State Railways of Thailand21618-2162361929Henschel & Son1000 1000 mm 1 onRoyal State Railways of Thailand23109-2311021936Henschel & Son1067 3 ft 6 in 1Sierra Leone Development Corporation678611937Beyer, Peacock & Company1067 3 ft 6 in 1Sierra Leone Development Corporation684211937Beyer, Peacock & Company1067 3 ft 6 in 1South African RailwaysGE6193-619861924Beyer, Peacock & Company1067 3 ft 6 in 1South African RailwaysGE6339-6348101927Beyer, Peacock & Company1067 3 ft 6 in 1Rhodesia Railways6562-656981929-30Beyer, Peacock & Company1067 3 ft 6 in 1South African RailwaysGE6716-671721930Beyer, Peacock & Company1067 3 ft 6 in 1Sierra Leone Development Corporation6726-672721931Beyer, Peacock & Company1067 3 ft 6 in 1Rhodesia Railways6877-688261938Beyer, Peacock & Company1067 3 ft 6 in 1Rhodesia Railways6899-690461937Beyer, Peacock & Company1067 3 ft 6 in 1War Department, Congo/Gold Coast/Rhodesia7057-7074181943Beyer, Peacock & Company1067 3 ft 6 in 1Rhodesia Railways7498-7527301953Beyer, Peacock & Company1435 4ft8.5in 1 onCentral of Peru673111931Beyer, Peacock & Company1435 4ft8.5in 1 onNitrate Railways, Chile6291-629331926Beyer, Peacock & Company1435 4ft8.5in 1 onNitrate Railways, Chile6481-648331928Beyer, Peacock & Company1435 4ft8.5in 1 onCentral of Peru6626-662831930Beyer, Peacock & Company1676 5 ft 6 in 1 onCentral of Aragon, Spain402-40761931Babcock & Wilcox, Spain1676 5 ft 6 in 1 onRenfe, Spain730-739101960Babcock & Wilcox, Spain Modified Fairlie locomotives The South African Railways (SAR), where the Modified Fairlie concept was conceived as a possible alternative to the Garratt, was the only user. The Modified Fairlie was essentially 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.43-45, 52-5312, 91, 98The Fairlie locomotive Usage South Africa Between 1925 and 1931, the SAR placed eighteen Cape on Class GE Garratts in service, all built by Beyer, Peacock & Company between 1924 and 1930. The first six entered service in 1925 and proved so successful that a second order for ten was placed in 1926. Another two locomotives entered service in 1931. All of them had Belpaire fireboxes, plate frames, Walschaerts valve gear and were superheated. The locomotive was an enlargement of the Class GD 2-6-2+2-6-2 Double Prairie and was designed as a heavy goods locomotive for use on light 60 lb/yd kg/m 0 off rail. They were the first eight-coupled Garratts to be built for the SAR and, on a tractive effort basis at the time of their introduction, they were the most powerful locomotives operating on light track in Africa and the Southern Hemisphere.South African Railways and Harbours Locomotive Diagram Book, 2’0” & 3’6” Gauge Steam Locomotives, 15 August 1941, as amended31-32, 111 thumb|SAR Class HF no. 1386, c. 1950 In 1927, the SAR placed ten Class HF Modified Fairlie Double Mikados in service, followed by an eleventh one in 1928. The locomotive was designed by the SAR under the direction of Colonel F.R. Collins DSO, SAR Chief Mechanical Engineer from 1922 to 1929, and was built by Henschel & Son in 1926 and 1927, hence the designation of Class HF for "Henschel Fairlie". Designed for mainline work, it was the Modified Fairlie equivalent of the Class GE Garratt which was similar in both size and mechanical respects. It had Walschaerts valve gear, a bar frame and was superheated, with a round-topped firebox.Henschel-Lieferliste (Henschel & Son works list), compiled by Dietmar Stresow The Class HF proved to be a powerful locomotive, but it was less successful than its Garratt equivalent. The pivot bearings were subject to quite rapid wear since they carried a considerable additional load compared to those on the Garratt, as a result of the water and coal bunkers which were mounted on the main frame instead of on the engine units. This resulted in increased maintenance and, as a consequence, increased operating cost. No more locomotives of the Modified Fairlie design were acquired by the SAR. References External links 8,2-8-2