Under the

Whyte notation 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 twentieth cen ...

for the classification of steam locomotives 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 An articulated locomotive is a steam locomotive (rarely, an electric locomotive) with one or more engine units that can move independent of the main frame. Articulation allows the operation of locomotives that would otherwise be too large to neg ...

of the Garratt 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, centr ...

and cab suspended between the two power units. Each power unit has no

leading wheel The leading wheel or leading axle or pilot wheel of a steam locomotive is an unpowered wheel or axle located in front of the driving wheels. The axle or axles of the leading wheels are normally located on a leading truck. Leading wheels are used ...

s, four powered and coupled driving wheels 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) located behind the driving wheels. The axle of the trailing wheels is usually located in a trailing truck. On some large locomotives, ...

s. A similar arrangement exists for Mallet and Meyer locomotives, but is referred to as .

Overview

The first Garratt locomotive, K1, one of two gauge

Tasmanian Government Railways K class The Tasmanian Government Railways K class was a class of 0-4-0+0-4-0 Garratt articulated steam locomotives operated by the Tasmanian Government Railways from 1909 – the first Garratt locomotives built. Overview Although considered the first ...

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) or Rheilffordd Eryri is a long, restored narrow gauge heritage railway in the Welsh county of Gwynedd, operating from Caernarfon to Porthmadog, and passing through a number of popular tourist destinations ...

. This arrangement proved one of the less popular Garratt types, since most Garratt locomotives were larger and more powerful, requiring more pairs of driving wheels to operate within the normal

axle load An axle or axletree is a central shaft for a rotating wheel or gear. On wheeled vehicles, the axle may be fixed to the wheels, rotating with them, or fixed to the vehicle, with the wheels rotating around the axle. In the former case, bearin ...

limits, and because

s gave more stability and better tracking to allow faster speeds. In total, 34 Garratts of this type were constructed, seven by Garratt patent holder Beyer, Peacock & Company, 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 (french: Congo belge, ; nl, Belgisch-Congo) was a Belgian colony in Central Africa from 1908 until independence in 1960. The former colony adopted its present name, the Democratic Republic of the Congo (DRC), in 1964. Colo ...

, 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 ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...

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 effici ...

'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, 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

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 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 stages were used in shi ...

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.Bressingham Steam Museum. This locomotive had its engine units arranged back-to-back in the usual Garratt fashion.

References

External links

{{Whyte types 4,0-4-0