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 a
Garratt 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 ...
. The wheel arrangement is effectively two
4-6-4 locomotives operating back to back, 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 engine units. Each engine unit has two pairs of
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 in a leading bogie, followed by three coupled pairs of
driving wheels and two pairs of trailing wheels in a trailing bogie.
Overview
The was the fifth most common Garratt wheel arrangement, with 84 locomotives constructed, 74 by Garratt patent owner
Beyer, Peacock & Company between 1936 and 1950 and ten under sub-contract from Beyer, Peacock by
Belgian
Belgian may refer to:
* Something of, or related to, Belgium
* Belgians, people from Belgium or of Belgian descent
* Languages of Belgium, languages spoken in Belgium, such as Dutch, French, and German
*Ancient Belgian language, an extinct languag ...
manufacturer
Société Franco-Belge
The Société Franco-Belge was a Franco-Belgian engineering firm that specialised in the construction of railway vehicles and their components and accessories. The company originated in 1859 as the Belgian firm Compagnie Belge pour la Constructio ...
in 1952.
Only three railway systems used this wheel arrangement. These were the
Sudan Railways
Sudan has 4,725 kilometers of narrow-gauge, single-track railways. The main line runs from Wadi Halfa on the Egyptian border to Khartoum and southwest to El-Obeid via Sannar and Kosti, Sudan, with extensions to Nyala in Southern Darfur and Wau ...
with ten locomotives of the
250 class and the
Rhodesia Railways
The National Railways of Zimbabwe (NRZ), formerly Rhodesia Railways, is a state-owned company in Zimbabwe that operates the country's national railway system.
It is headquartered in the city of Bulawayo. In addition to the headquarters, it has ...
, now the
National Railways of Zimbabwe
The National Railways of Zimbabwe (NRZ), formerly Rhodesia Railways, is a state-owned company in Zimbabwe that operates the country's national railway system.
It is headquartered in the city of Bulawayo. In addition to the headquarters, it has ...
, who owned 74, split between 34 of the
15th class and 40 of the 15A class. The Sudanese locomotives were later sold to Rhodesia who, in turn, subsequently sold them to
Caminhos de Ferro de Moçambique
Portos e Caminhos de Ferro de Moçambique (abbreviated CFM; in English Mozambique Ports and Railways) is a state-owned company that oversees the railway system of Mozambique and its connected ports.
The rail system is composed of a total of 2,9 ...
.
Usage
Mozambique
In 1964, ten ex-Sudanese 250 class locomotives were purchased by the
Caminhos de Ferro de Moçambique
Portos e Caminhos de Ferro de Moçambique (abbreviated CFM; in English Mozambique Ports and Railways) is a state-owned company that oversees the railway system of Mozambique and its connected ports.
The rail system is composed of a total of 2,9 ...
from the Rhodesia Railways, who had acquired them from Sudan c. 1949 and used them as their 17th class. In Mozambique, they were used on the
Beira railway Beira can refer to:
* Beira (mythology), the mother to all the gods and goddesses in the Celtic mythology of Scotland
*Beira, Azores, a small village on São Jorge Island
* Beira (Portugal), the name of a region (and former province) in north-cent ...
from the port city of
Beira to the Rhodesian (now Zimbabwean) border at Umtali (now
Mutare). They remained in use into the 1980s, but their ultimate post-civil war fate is unclear and all of them are presumed to have been scrapped.
Southern Rhodesia
The Rhodesia Railways (RR)
15th class 4-6-4+4-6-4 was the second most numerous class of
Garratt locomotives, with 74 locomotives built. Only the
South African Class GMA Double Mountain was more numerous at 120 locomotives.
The 15th class was a development of the RR 16th class 2-8-2+2-8-2 Garratts, to meet a requirement for a locomotive with a larger driving wheel diameter for higher speed train service on the more level parts of the railway. After examining the Sudan Railways 250 class, the RR settled on a design with the same wheel arrangement and the same diameter driving wheel diameter as that of the Sudanese Double Baltics.
Initially four locomotives were ordered in 1940, and having proved their worth, a further seventy locomotives were ordered in five batches after the Second World War. The last forty locomotives were designated as the 15A class, since they had boilers with the rated pressure increased from .
Sudan
Ten 4-6-4+4-6-4 Garratt locomotives of the
Sudan Railways 250 class were built in two batches for the
Sudan Railways
Sudan has 4,725 kilometers of narrow-gauge, single-track railways. The main line runs from Wadi Halfa on the Egyptian border to Khartoum and southwest to El-Obeid via Sannar and Kosti, Sudan, with extensions to Nyala in Southern Darfur and Wau ...
by Beyer, Peacock in 1936 and 1937. They were the only Garratt types on the Sudan Railways and were used on the
Port Sudan
Port Sudan ( ar, بور سودان, Būr Sūdān) is a port city in eastern Sudan, and the capital of the state of Red Sea. , it has 489,725 residents. Located on the Red Sea, Port Sudan is recognized as Sudan's main seaport and the source of 90% ...
to
Atbara
Atbara (sometimes Atbarah) ( ar, عطبرة ʿAṭbarah) is a city located in River Nile State in northeastern Sudan.
Because of its links to the railway industry, Atbara is also known as the "Railway City'.
As of 2007, its population is 1 ...
and Atbara to
Wad Madani
Wad Madani ( ar, ود مدني, Wad Madanī) or Madani is the capital of the Al Jazirah state in east-central Sudan.
"Wad Madani" (population), Microsoft Encarta, Online Encyclopedia 2001.
Wad Madani lies on the west bank of the Blue Nile, n ...
routes, until they were made redundant by diesel locomotives in 1949.
They were then sold to the
Rhodesia Railways
The National Railways of Zimbabwe (NRZ), formerly Rhodesia Railways, is a state-owned company in Zimbabwe that operates the country's national railway system.
It is headquartered in the city of Bulawayo. In addition to the headquarters, it has ...
, where they were designated 17th class and used alongside the RR’s 15th and 15A classes. In 1964, all ten locomotives were sold to the
Caminhos de Ferro de Moçambique
Portos e Caminhos de Ferro de Moçambique (abbreviated CFM; in English Mozambique Ports and Railways) is a state-owned company that oversees the railway system of Mozambique and its connected ports.
The rail system is composed of a total of 2,9 ...
.
References
External links
{{Whyte types
6,4-6-4
66,4-6-4+4-6-4