Under the

Whyte notation The Whyte notation is a classification method for steam locomotives, and some internal combustion locomotives and electric locomotives, by wheel arrangement. It was devised by Frederick Methvan Whyte, and came into use in the early twenti ...

for the classification of

steam locomotive A steam locomotive is a locomotive that provides the force to move itself and other vehicles by means of the expansion of steam. It is fuelled by burning combustible material (usually coal, Fuel oil, oil or, rarely, Wood fuel, wood) to heat ...

s by

wheel arrangement In rail transport, a wheel arrangement or wheel configuration is a system of classifying the way in which wheels are distributed under a locomotive. Several notations exist to describe the wheel assemblies of a locomotive by type, position, and c ...

, the is an articulated locomotive of the

Garratt A Garratt locomotive is a type of articulated steam locomotive invented by the engineer Herbert William Garratt that is articulated into three parts. Its boiler, firebox, and cab are mounted on a centre frame or "bridge". The two other ...

type. The wheel arrangement is effectively two locomotives operating back-to-back or face-to-face, with the

boiler A boiler is a closed vessel in which fluid (generally water) is heated. The fluid does not necessarily boil. The heated or vaporized fluid exits the boiler for use in various processes or heating applications, including water heating, centra ...

and cab suspended between the two power units. Each power unit has no leading wheels, four powered and coupled

driving wheel On a steam locomotive, a driving wheel is a powered wheel which is driven by the locomotive's pistons (or turbine, in the case of a steam turbine locomotive). On a conventional, non-articulated locomotive, the driving wheels are all coupled t ...

s on two axles and no

trailing wheel On a steam locomotive, a trailing wheel or trailing axle is generally an unpowered wheel or axle (Wheelset (rail transport), wheelset) located behind the driving wheels. The axle of the trailing wheels is usually located in a trailing Bogie, t ...

s. A similar arrangement exists for

Mallet A mallet is a tool used for imparting force on another object, often made of rubber or sometimes wood, that is smaller than a maul or beetle, and usually has a relatively large head. General overview The term is descriptive of the ...

, Meyer and Fairlie locomotives, but is referred to as .

Overview

The first Garratt locomotive, K1, one of two gauge Tasmanian Government Railways K class locomotives built in 1909, has this wheel arrangement and has been restored to operating condition at the

Welsh Highland Railway The Welsh Highland Railway (WHR; ) is a restored Narrow-gauge railway, narrow-gauge heritage railway in the Welsh county of Gwynedd. It runs from Caernarfon to Porthmadog, and passes through a number of popular tourist destinations includi ...

. This arrangement proved one of the less popular Garratt types, since most Garratt locomotives were larger and more powerful, requiring more pairs of

s to operate within the normal

axle load The axle load of a wheeled vehicle is the total weight bearing on the roadway for all wheels connected to a given axle. Axle load is an important design consideration in the engineering of roadways and railways, as both are designed to tolerate a m ...

limits, and because leading wheels gave more stability and better tracking to allow higher speeds. In total, 34 Garratts of this type were constructed, seven by Garratt patent holder

Beyer, Peacock & Company Beyer, Peacock and Company was an English general engineering company and railway locomotive manufacturer with a factory in Openshaw, Manchester. Charles Beyer, Richard Peacock and Henry Robertson founded the company in 1854. The company close ...

, mostly for industrial use, and 27 by other builders. The largest user of the type was the ''C.F. Vicinaux du Mayumbe'' in the

Belgian Congo The Belgian Congo (, ; ) was a Belgian colonial empire, Belgian colony in Central Africa from 1908 until independence in 1960 and became the Republic of the Congo (Léopoldville). The former colony adopted its present name, the Democratic Repu ...

, with twenty locomotives built to a gauge by St Leonard in Belgium.

Use

Argentina

The gauge Southern Fuegian Railway (F.C.A.F.) in

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

procured a new Garratt in 1994. Based on

Livio Dante Porta Livio Dante Porta (21 March 1922 – 10 June 2003) was an Argentine steam locomotive engineer. He is particularly remembered for his innovative modifications to existing locomotive systems in order to obtain better performance and energy effi ...

's work, it included larger cross section tubing, insulation of the boiler and an improved front end. This vastly improved the economy of this modern steam engine and more than doubled train length. Accordingly, a second Garratt for this railway was built to similar specifications, but with superheating added, in the workshops of Girdlestone Rail in

Port Shepstone Port Shepstone is a large town situated on the mouth of the Mzimkhulu River, the largest river on the KwaZulu-Natal South Coast of South Africa. It is located halfway between Hibberdene and Margate, KwaZulu-Natal, Margate and is positioned 120&nbs ...

, South Africa. It was shipped to Argentina in 2006 and entered service in October of that year. These locomotives had their engine units arranged face-to-face.

Australia

The Tasmanian Government Railways K class was the first class of Garratt locomotive ever produced. They differed from most later Garratts in two respects. * They were

compound locomotive A compound locomotive is a steam locomotive which is powered by a compound steam engine, compound engine, a type of steam engine where steam is expanded in two or more stages. The locomotive was only one application of compounding. Two and three ...

s, with two high-pressure cylinders on the rear engine unit and two larger low-pressure cylinders on the front engine unit. * Their engine units were arranged with their cylinders facing each other, rather than back-to-back as on most other Garratts.''Steam Locomotives of the Tasmanian Government Railways and its Constituents.''

Australian Railway History ''Australian Railway History'' is a monthly magazine covering railway history in Australia, published by the New South Wales Division of the Australian Railway Historical Society on behalf of its state and territory Divisions. History and prof ...

, issue 917, March 2014, p. 19.

United Kingdom

In addition to K1 at the Welsh Highland Railway, the industrial Beyer-Garratt ''William Francis'', built in 1937, is preserved at the Bressingham Steam Museum. This locomotive had its engine units arranged back-to-back in the usual Garratt fashion.

References

{{Whyte types 4,0-4-0