- Garratt
:"For people named Garratt, see
Garratt (surname) "A Garratt is a type of
steam locomotive that is articulated in three parts. Itsboiler is mounted on the centre frame, and twosteam engines are mounted on separate frames, one on each end of the boiler. Articulation permits larger locomotives to negotiate curves and lighter rails that might restrict large rigid-framed locomotives. Many Garratt designs aimed to double the power of the largest conventional locomotives operating on their railways, thus reducing the need for multiple locomotives and crews.Locomotive development
The Garratt articulated locomotive was developed by
Herbert William Garratt , a British locomotive engineer who, after a career with British colonial railways, was theNew South Wales Railways ' Inspecting Engineer inLondon . He first applied for apatent on the idea in 1907, after observing articulated gun carriages.Fact|date=February 2007 Garratt first approachedKitson & Co. , but his idea was rejected, perhaps because that company were already committed to the Kitson-Meyer.Fact|date=February 2007 He then approachedBeyer, Peacock and Company , who were only marginally more interested.Fact|date=February 2007The first Garratts
In 1907 Beyer, Peacock & Co. submitted a proposal for a 2' gauge
0-4-0+0-4-0 Garratt to the New South Wales Government Railways, which was not proceeded with. The following year a design for a 2' (610 mm) gaugeMallet locomotive was submitted in reply to an enquiry from the Tasmanian Government. This was followed with a submission for a Garratt based on, but a little heavier than, the New South Wales proposal. This proposal was accepted; two locomotives were built in 1909, which became the K class. [Belbin, B., Browning, J, & McKillop, B. "K1 Steams Again" in Light Rails No. 193, February 2007, p.4]Unlike in Garratt's patent, Tasmanian Railways insisted on a compound arrangement with cylinders facing inwards, in order to reduce the distances between both the main steam pipe and the high-pressure cylinders, and between the high-pressure and low-pressure cylinders.Fact|date=February 2007 This made the locomotive unnecessarily complicated and placed the high-pressure cylinders directly underneath the cab, making it uncomfortably hot, especially in summer.Fact|date=February 2007 The pattern was not repeated on later Garratt designs. Only one more Garratt locomotive, again built by Beyer, Peacock & Co., was produced with compound propulsion.Fact|date=February 2007
Early design and construction difficulties involved the steam-tight flexible connections between the boiler unit and the power units. These were solved by Beyer, Peacock's designers after studying a description of the spherical steam joints used on a
Fairlie locomotive built for theFfestiniog Railway followed by a visit to the FR to observe these locomotives at work. [ Rolt L.T.C., "A Hunslet Hundred" David & Charles, Dawlish, 1964, (page 66) quoted by Tom Rolt from Edgar Alcock regarding his time at Beyer Peacock.]Darjeeling Himalayan Railway
The third Garratt (an 0-4-0+0-4-0, like the first two) was a class "D" built in 1910 for the
Darjeeling Himalayan Railway . As with many early Garratt classes, this engine's dimensions and power were designed to be roughly equivalent to those of two of the line's existing 0-4-0T engines, although in practice it achieved only a 65% increase in loading. [Hughes, Hugh (1994). "Indian Locomotives Part 3 Narrow Gauge 1865-1940". Continental Railway Circle, Kenton. ISBN 0952165503. p.37] The "D" class was true to Garratt's patent, without compounding of the cylinders and with the cylinders facing outwards. It also incorporated Beyer, Peacock's first improvement to the design, placing the engine unit pivot above the rear axle rather than between the two axles, as Garratt specified.Fact|date=February 2007 This allowed the design to evolve into larger and more powerful locomotives. Although technically successful, the locomotive was underutilized and withdrawn in 1954. [Hughes. p.37]First main-line class
In 1911
Beyer, Peacock and Company built six2-6-0+0-6-2 Garratts for theWestern Australian Government Railways . The M class locos were followed by the Ms and the Msa class. These were the first Garratts built for main line use, the first built in large numbers, and the first design to be repeated and developed.Fact|date=February 2007 They also formed the pattern for locos for the Victorian Railways G class, and for Australian Portland Cement.cite book |author=Durrant, A.E. |title=Garratt Locomotives of the World |publisher=David & Charles |year=1981 |id=ISBN 0-7153-7641-1]Beyer-Garratt
Garratt licensed the British firm of
Beyer, Peacock and Company to build locomotives to his patent design.Fact|date=February 2007 As well as producing locomotives, Beyer, Peacock developed and marketed the design, licensing it to other builders. After the original Garratt patents expired in 1928, Beyer, Peacock continued to market Garratts under its own brand, Beyer-Garratt.Fact|date=February 2007 With continuing development and patent improvements, Beyer, Peacock maintained its leadership with the Garratt, and just under two-thirds of all Garratt locomotives (1023 of 1651) were built at Beyer, Peacock'sGorton Foundry .Fact|date=February 2007 The remainder were constructed by a number of licensees and a small number by non-licensed builders. Garratts were built in Britain,France ,Spain ,Germany ,Italy ,Belgium ,South Africa ,Brazil , andAustralia .Fact|date=February 2007Final Garratts constructed
The final
Garratt s were built in 1967-8, eight RailGauge|2ft gauge South African RailwaysSAR NGG 16 Class . The order was placed withBeyer, Peacock and Company , but as it was in the process of closing down it subcontracted the order to theHunslet Engine Company . Hunslet's South Africansubsidiary constructed most of these locomotives in South Africa.Garratts around the world
Garratts were used in
Africa ,Asia ,Australia ,Europe andSouth America . No Garratts were used on North American railroads, the most likely explanation being that American rail companies considered the Garratt's coal and water capacities unequal to their requirements.Europe
Garratts were employed in Great Britain,
Russia andSpain , where some five railway companies employed seven classes. These included the 1931 order forCentral of Aragon Railway for six Double Pacific Garratts for fast passenger service. In Brazil, post-1927 theSão Paulo Railway operated broad-gauge4-6-2+2-6-4 Garratts which ran passenger trains at 70 m.p.h.("The Great Book of Trains", pp. 144-145) In Algeria 30 French-built4-6-2+2-6-4 Garratts with Cossart motion gear operated until the civil war caused their withdrawal in 1951. These engines were streamlined fast runners and performed well in mountainous regions.The
Rio Tinto Railway had two Beyer-Garratts used for hauling mineral trains of up to 2,000 tonnes downhill and 550 tonnes of empties uphill.Fact|date=February 2007British usage of Garratts was minimal. In the UK a single large Garratt (
2-8-0+0-8-2 ,London and North Eastern Railway Class U1 number 2395/9999/69999, was built in 1925 for banking heavy coal trains on the Woodhead route.Fact|date=February 2007 Thirty-three 2-6-0+0-6-2 locomotives were built for theLondon, Midland and Scottish Railway and several0-4-0+0-4-0 s for industrial use, one of which is preserved atBressingham Steam and Gardens .Fact|date=February 2007 The Garratt design was not generally used on British railways as most goods trains were short and light, on railways with broad curves and moderate grades compared with elsewhere in the world.Fact|date=February 2007Beyer, Peacock constructed the largest steam locomotive built in Europe, a
4-8-2+2-8-4 for the USSR, works order number 1176 in 1932. The locomotive had the Russian classification Ya.01 (Я.01). This massive machine was built to the Russian standard RailGauge|60 gauge and a loading gauge height of convert|17|ft|m. It underwent extensive testing and proved to be very able to operate in extremely low temperatures, due to adequate protection of the external plumbing between boiler and engine units. This may have been the lowest temperature operation of a Garratt type. The locomotive was used for a number of years for coal traffic in the Donbass region, but was never replicated. This decision appears to be a combination of unfamiliar maintenance processes and politics. ("Locomotives", A.M.Bell) ("Russian Steam Locomotives", LeFleming/Price) ("Locomotives of Russia 1845 - 1955", V.A.Rakov). The Russians later experimented with Mallet locomotives, the P342-6-6-2 and the P382-8-8-4 .Fact|date=February 2007Africa
The Garratt was most widely used in
Africa with Zimbabwe maintaining an average of four locomotives to perform shunting duties around the city of Bulawayo. The most powerful of all Garratts irrespective of gauge were the South African Railways' eight GL class locomotives of 1929-30, which delivered convert|89130|lbf|kN|2|abbr=on oftractive effort .South African Government, "South Africa - Last Stronghold of Steam", Johannesburg, 1978. ISBN 0-949934-24-0]The largest and most powerful locomotives to run on the metre gauge were the
East African Railways , 59 Class Garratt,4-8-2+2-8-4 s, which delivered a tractive effort of convert|83350|lbf|kN|2|abbr=on. These 34 East African Garratts had a large convert|70|sqft|abbr=on grate and a reputation as amongst the largest and most powerful steam locomotives in the world.Hollingsworth, Brian. & Cook, Arthur. "The Great Book of Trains", 1987, Lifetime Distributors, ISBN 0-86101-919-9]outh America
Argentina
The British-owned
Buenos Aires Great Southern Railway (RailGauge|5ft6in gauge) operated 12 Garratt4-8-2+2-8-4 oil-fired locomotives, numbers 4851-4862, built by Beyer, Peacock in 1929. They were used on the Bahia Blanca North Western section (particularly on theToay line), on the main Bahia Blanca North Western line toPico , and betweenTres Arroyos andBahia Blanca . They were withdrawn in the 1950s due to the rapid decline in freight traffic caused by the increasing competition from road transport.D.S.Purdom, British Steam on the Pampas, Mechanical Engineering Publications Ltd, London, 1977 ] The F.C.A.F in Ushuaia uses two 500 mm gauge Garratts to haul tourists into a National Park.Other British-owned railway companies operated Garratt locomotives built by Beyer, Peacock as follows:
Argentine North Eastern (RailGauge|ussg gauge): 7 2-6-0+0-6-2 locomotives built 1925-1927 and 3 4-4-2+2-4-4, 1930.
Argentine Transandine (RailGauge|1 gauge): 4 2-6-2+2-6-2, 1930.
Buenos Aires and Pacific (RailGauge|5ft6in gauge): 4 4-8-2+2-8-4, 1929-1930.
Buenos Aires Midland (RailGauge|1 gauge): 2 4-6-2+2-6-4, 1930.
Cordoba Central (RailGauge|1 gauge) : 10 4-8-2+2-8-4, 1929.
Entre Rios (RailGauge|ussg gauge): 5 2-6-0+0-6-2 and 5 4-4-2+2-4-4, 1927.Australia
The
New South Wales Government Railways introduced the4-8-4+4-8-4 AD60 Garratt in 1952, built by Beyer, Peacock. The AD60 weighed 265 tonnes, with a 16-tonne axle loading. As delivered, it developed atractive effort of 60,000 lbf (265 kN), not as powerful as the South African Railways GMA/M4-8-2+2-8-4 Garratts of 1954, which developed a tractive effort of 60,700 lbf (270 kN).pp. 50-51] Following modifications in 1958 to 30 AD60s, their tractive effort was increased to convert|63016|lbf|kN|abbr=on. [Oberg, Leon. (1975) "Australian Locomotives." p.200. Oberg wrote he witnessed an AD60 clear a dead 1220-tonne double-headed diesel freight (total weight 1450 tonnes) from a 1 in 55 grade without wheel slip (p.191).]Following the success of the K class Garratts on the
North East Dundas Tramway ,Tasmanian Government Railways imported Beyer, Peacock Garratts for their main lines, in particular the4-4-2+2-4-4 M class for express passenger work. These were the only eight-cylinder Garratts. [Cooper, Greg; Grant Goss (1996). "Tasmanian Railways - 125 Years"] The M1 achieved a world speed record of 55 mph (90 km/h), on30 November 1912 . Their 5-foot (1.5 m) diameter driving wheels were at the time the largest on any narrow-gauge locomotive in Australia. [Cooper. p.19] Their eight cylinders proved a nightmare to maintain, and after several fatal and disastrous derailments in the late 1920s, mainly due to inadequate trackwork, they were withdrawn and scrapped.The
Queensland Railways operated 30 Beyer Garratt locomotives. These were mainly based in the Rockhampton area ["Those QR Beyer, Garratts which gave Very Little Trouble" Knowles, John Australian Railway Historical Society Bulletin, January, 1998 pp13-20] .New Zealand
Beyer, Peacock built three
4-6-2+2-6-4 NZR G class locomotives in 1928, which were unsuccessful. Unusually, these engines had three cylinders (24×16.5 in) on two sets of engine frames, thus creating a six-cylinder Garratt; they were the second and final Garratts to employ this arrangement, the other being the aforementioned LNER U1. They entered service in 1929.Walschaerts valve gear operated the outside cylinders with the inner third cylinder linked by aGresley conjugated valve gear . The most likely reasons for these locomotives being failures were that they were too powerful for the system and they had complicated valve mechanisms. Photos verify the coal bunker was carried on an extension to the boiler frame rather than on the rear engine frame, as with most Garratts. The engines delivered convert|51580|lbf|kN|2|abbr=on of tractive effort, which on light NZR track was too powerful for the drawbars on rolling stock. After a few years they were rebuilt as six Pacifics, also unsuccessful, but which saw nearly twenty years of service. [Stewart, W. W. (1970). "When Steam Was King". A.H.& A.W. Reed, Wellington. pp.98-104.]Advantages of the Garratt concept
The principal benefit of the Garratt design is that the
boiler andfirebox unit are slung between the two engine units. This frees the boiler and firebox from the size constraints imposed where they are placed over the frames and running gear, as in conventional designs and other articulateds such as Mallets. Garratts can have a boiler with a greater diameter, which increases heating area and aids the production ofsteam . The boiler can also be shorter than other designs with the same heating area. In some loco designs, the boiler is so long almost no heating of the water occurs at thesmokebox end of the boiler. A larger firebox promotes more efficient combustion offuel and also increases the heat available to the boiler.Fact|date=February 2007Garratts enjoy an advantage over the Mallet system, because of the geometry of the design. When swinging around curves the boiler and cab unit move inward like a bowstring in the bow of a curve and this reduces the centrifugal force that would overturn a normal locomotive and which in turn permits fast running. The Mallet's forward articulated unit tends to throw out as the loco rounds curves. . While most Garratts were designed for freight or mixed traffic, there were a number of passenger Garratt classes. A Garratt holds the world speed record for an articulated locomotive.Fact|date=February 2007
Garratts have several advantages when used on light and
narrow gauge railways. They aretank locomotive s, thus eliminating the need for expensive turntables or wyes. They don’t need to be run through to terminals increasing operational flexibility. Because the engine units are separated by the boiler unit, the weight of the locomotive is split over the two units. Therefore they can run over bridges that might not be able to support conventional or Mallet locomotives of similar weight.Fact|date=February 2007Whilst at the end of steam most conventional steam locomotives had reached their maximum in 'critical dimensions', the Garratt still had some way to go, with larger driving wheels, larger boilers and greater output still achievable.
Disadvantages of the Garratt concept
The major disadvantage of a Garratt (shared with all
tank engine s) is that the tractive weight reduces as the water is used from the front tank and coal from the rear bunker. As the weight on the wheels reduces slipping occurs. To reduce wheel slippage, a wagon containing water was attached behind the Garratt, and this practice also permitted the engine to operate over longer distances.Fact|date=February 2007 The weight of the water in the locomotive's tank and weight of coal in the bunker (necessary for the factor of adhesion) was predicted in advance, and this problem was not normally an operational issue.Fact|date=February 2007Another disadvantage is that both power units are controlled by one regulator, thus if one power unit slipped the steam to both was reduced as the driver tried to control the slip.Fact|date=February 2007
The Garratt had a safety problem in Western Australia when operating through a narrow-profile single-track tunnel. Should a Garratt stall in a narrow tunnel the crew could be trapped, since there was no route forward or backwards past the hot cylinders. A normal engine has hot cylinders at one end with an escape route at the other end. Two crew members died in
Western Australia in the 1940s when anAustralian Standard Garratt stalled in the state's only tunnel, theSwan View Tunnel .Competitors, look-alikes, and variations on the theme
The Garratt was, obviously, not alone in the field of articulated locomotives. Aside from the well-known
Fairlie andMeyer types, the Garratt had contemporary and similarly-designed competition in the form of the Union-Garratt, Modified Fairlie andGolwe . Of these, the closest was the Union-Garratt, a type originally conceived owing to the perceived necessity for a rigid connection between a bunker or tender and a firebox fed by a mechanical stoker. Though it could be argued that the NZR G class locomotives were Union-Garratts (having their bunkers mounted on the boiler frames, rather than on the hind engine unit), a more concrete example can be seen in the two South African Railways Union Garratts of classes GH and U.The Union-Garratt did not enjoy the success of the standard Garratt. It was soon evident that mechanical stokers could function perfectly across the connection between a Garratt's boiler and engine unit, making the rationale for the Union-Garratt obsolete. The Union-Garratts' extended boiler frames and the position of the bunker and hind water tank upon those frames meant that they suffered from many of the problems which beset the Mallet design; the SAR U and GH classes had much heavier axle-loadings than Garratts of comparable size, weight and power, and the movement of water at the extreme ends of the long main frames generated high wear on the hind pivot between the boiler and engine unit. The Union-Garratt, like the Golwe and Modified Fairlie, was not perpetuated on anything like the scale of the Garratt, and no known examples survive.
War locomotives
During
World War II , several Garratt designs were built to meet the wartime needs of narrow-gauge railways in Africa, Asia and Australia.Six
2-6-2+2-6-2 Garratts were built for the 2' 6" (762 mm) gaugeSierra Leone Government Railway in 1942, to a design first supplied to that railway in 1926. Five of the older Garratts were converted to a2-8-0+0-8-2 wheel arrangement to increase theirtractive effort .Seventy Garratts were constructed by Beyer, Peacock for the War Department, to three standard designs. A
2-8-2+2-8-2 based on the South African Railways GE class was constructed on 3' 6" (1067 mm) gauge for West Africa andRhodesia , while a heavier class of4-8-2+2-8-4 was constructed forEast African Railways . A lighter metre-gauge4-8-2+2-8-4 was constructed for India and Burma. This design was particularly successful, and was the basis for several post-war classes.The
Australian Standard Garratt (ASG) was constructed for Australian convert|3|ft|6|in|m|abbr=on gauge railways. It was a4-8-2+2-8-4 locomotive was designed and constructed in Australia in 1943, during the crisis days ofWorld War II immediately following the bombing of Darwin in 1942.Butlin, S.J. Australia in the War of 1939-1945: Vol 111, War Economy 1939-1942. Australian War Memorial, Canberra, 1961] The class had several design problems, and encountered resistance from unions, and most were withdrawn at war's end.Preservation
Around 250 Garratts exist today. While many are stored or dumped in various stages of disrepair, more than 100 are preserved in
museum collections or onheritage railway s. Operating Garratt locomotives can be found in Europe, Africa,India and Australia. [Hamilton, G. [http://users.powernet.co.uk/hamilton/survivors.html Surviving Garratt Locomotives] accessed5 March 2007 ] In Spain occasionally runs an 2-8-2+2-8-2 , number 282F-0421, nicknamed "Garrafeta"in Lerida area. An enormous 4-6-2+2-6-4, number 462F-0401, is actually under restoration. Both locomotives are managed by ARMF, a non-profit organisation which also holds the only main line repair workshop for historical railway vehicles on broad gauge network. [www.armf.net]A single Hanomag-built narrow gauge example exists in the USA located in
Texas The first Garratt locomotive, the K class of the
North-East Dundas Tramway , has been preserved. After the line closed in 1929 the locomotives were put up for sale. K1 was purchased by Beyer, Peacock in 1947 for their museum. The preserved loco has parts from both original engines, including the boiler from K2. When Beyer, Peacock ceased trading, the locomotive was sold to theFfestiniog Railway , who initially proposed to cut it down to meet their loading gauge. For a number of years it was on loan to theNational Railway Museum and exhibited inYork . In 1995 it was removed from York to commence restoration in Birmingham. It was returned toWales in 2000 where restoration was continued at the Ffestiniog Railway workshops atBoston Lodge . It was fitted with a new boiler and restored to full running order on theWelsh Highland Railway in September 2006. The Welsh Highland Railway owns several former South AfricanSAR NGG 16 Class Garratts, and operates both the first and last Garratts constructed by Beyer, Peacock. [Belbin & McKillop. pp.6-7]Several
Australia n Garratts have been restored to operating condition. G 42, formerly used on thenarrow gauge lines of the Victorian Railways , now works regularly on thePuffing Billy Railway in theDandenong Ranges outsideMelbourne . [The PBR site (accessed 2008-05-09) lists their G Class in regular service.] TheQueensland Rail ways removed 1009, its sole remaining 3' 6" (1067 mm) gauge4-8-2+2-8-4 Garratt, from an open air museum and fully restored it to working order. It was out of service in December 2007, awaiting a new boiler which Queensland Rail plans to construct itself. In late 2007 work commenced to overhaul N.S.W.G.R. AD60 6029 to operating condition in Canberra.In
Kenya , East African Railways 59 class 5918 is maintained in operating condition. InZimbabwe 20th class 730 is held in operating condition but has not worked since 2001.In
South Africa , a restored main-line 3' 6" (1067 mm) gauge GMAM class Garratt 4079 operates as a tourist attraction and was used in 2006 on a specialRovos Rail tour. AtPietermaritzburg inKwaZulu-Natal a 2' (610 mm) gauge Garratt is operational on a short tourist line. Fact|date=February 2007In December 2007, Zimbabwe class 14A Garratt number 509, overhauled in Bulawayo was offloaded in New Zealand for operational preservation by the Main Line Steam trust [
RailwaysAfrica 2008/1 p 34 ]References
Web Sites
* [http://users.powernet.co.uk/hamilton/ A Complete List of All Garratt Locomotives] , "Gavin Hamilton"
* [http://whr.bangor.ac.uk/k1.htm K1 The World's First Garratt] , "Ben Fisher"
* [http://www.garrattmaker.com/ Karamoja,a Kenya-Uganda Garratt Locomotive] , "garrattmaker"
* [http://www.steamindex.com/people/garratt.htm Herbert William Garratt] .
* [http://users.powernet.co.uk/hamilton/pics5.html Illustrations of Garratts] .
* http://www.livesteaming.com/beyer-garratts.htm The first the last and the largest in the 21st Century
* [http://www.garrattmaker.com/history.html]
Wikimedia Foundation. 2010.