* 1 Overview
* 1.1 Development
* 1.2 Origin of the name
* 1.3 Global popularity
* 2 Usage
* 2.1 Argentina
* 2.2 Australia
* 2.3 Austria
* 2.4 Bulgaria
* 2.15 India
* 2.30 South Africa
* 2.35 Tunisia
* 2.36 United Kingdom
* 2.36.1 Tender locomotives
* 2.37 United States of America
* 3 References
The introduction of the
The type is generally considered to be an enlargement of the 4-4-2 Atlantic type, although its prototype had a direct relationship to the 4-6-0 Ten-wheeler and 2-6-2 Prairie , effectively being a combination of the two types. The success of the type can be attributed to a combination of its four-wheel leading truck which provided better stability at speed than a 2-6-2 Prairie , the six driving wheels which allowed for a larger boiler and the application of more tractive effort than the earlier 4-4-2 Atlantic , and the two-wheel trailing truck, first used on the New Zealand 2-6-2 Prairie of 1885. This permitted the firebox to be located behind the high driving wheels and thereby allowed it to be both wide and deep, unlike the 4-6-0 Ten-wheeler which had either a narrow and deep firebox between the driving wheels or a wide and shallow one above.
The type is well-suited to high speed running. The world speed record for steam traction of 126 miles per hour (203 kilometres per hour) has been held by a British Pacific locomotive, the Mallard , since 3 July 1938.
The two earliest
The first true Pacific, designed as such with a large firebox aft of
the coupled wheels, was ordered in 1901 by the New Zealand Railways
Department (NZR) from the
Baldwin Locomotive Works
ORIGIN OF THE NAME
There are different opinions concerning the origin of the name Pacific. The design was a natural enlargement of the existing Baldwin 4-4-2 Atlantic type, but the type name may also be in recognition of the fact that a New Zealand designer had first proposed it. Usually, however, new wheel arrangements were named for, or named by, the railroad which first used the type in the United States. In the case of the Pacific, that was the Missouri Pacific Railroad in 1902.
In the Cape of Good Hope in South Africa, the first Pacifics were delivered from Kitson and Company in 1903 and designated the Karoo Class , from the region of the Cape Western System of the Cape Government Railways that they were designed to work in.
The Pacific type was used on mainline railways around the world. The railways of New Zealand and Australia were the first in the world to run large numbers of Pacific locomotives, having introduced 4-6-2 types in 1901 and 1902 respectively and operating them until the 1960s. Builder's photograph of Altoona-built K5 no. 5698, 1929
During the first half of the 20th century, the Pacific rapidly became the predominant passenger steam power in North America. Between 1902 and 1930, about 6,800 locomotives of the type were built by North American manufacturers for service in the United States and Canada. With exported locomotives included, about 7,300 were built in total. About 45% of these were built by the American Locomotive Company (ALCO) which became the main builder of the type, and 28% by Baldwin. Large numbers were also used in South America, most of which were supplied by manufacturers in the United Kingdom, the United States and Germany. Cape Government Railways Enlarged Karoo Class, SAR Class 5
Africa was the third continent upon which the Pacific was regularly used, following the introduction of the Karoo class on the Cape Government Railways in the Cape of Good Hope in 1903. The earliest African examples were built in the United Kingdom by Kitson and Company .
The earliest examples of the Pacific in Europe were two French
prototypes, introduced in 1907 and designed by the Compagnie du chemin
de fer de Paris à Orléans (PO) to overcome the insufficient power of
their 4-4-2 Atlantics. Within a few weeks, these were followed by a
German Pacific type that, although already designed in 1905, only
entered service in late 1907. The next was a British type, introduced
in January 1908. By the outbreak of the
First World War
The Pacific type was introduced into Asia in 1907, the same year that it was first used in Europe. By the 1920s, Pacifics were being used by many railways throughout the Asian continent.
In 1923, the Pacific gave its name to
Arthur Honegger 's orchestral
During the first two decades of the 20th century, the Pacific wheel arrangement enjoyed limited popularity on tank locomotives . On a 4-6-2T locomotive, the trailing wheels support the coal bunker rather than an enlarged firebox and such a locomotive is therefore actually a tank engine version of the 4-6-0 Ten-wheeler tender locomotive. Indeed, many of the earliest examples were either rebuilt from tender locomotives or shared their basic design.
Around 1920, it became apparent to designers that the 4-6-2T wheel arrangement allowed a too limited bunker size for most purposes, with the result that most later designs of large suburban tank classes were of the 4-6-4T Hudson or 2-6-4T Adriatic wheel arrangement.
The LNER Peppercorn Class A1 60163 Tornado , built in 2008
The Pacific became the major express passenger locomotive type on
many railways throughout the 1920s, 1930s and 1940s. Examples were
also built for fast freight and mixed traffic duties. However, due to
the increasing weight of trains during the 1940s, larger developments
of the type became necessary in the United States and elsewhere. The
most notable of these was the
However, the story of the
The Vulcan Foundry built twenty Pacific locomotives for the former Buenos Aires Great Southern Railway (BAGSR) in 1926, two of which still survive. A further single 12B class locomotive was built in 1930, and the 12K class of twelve Pacific locomotives was built for the BAGSR by Vulcan in 1938. Central Argentine Railway (Ferrocarril Central Argentino) PS11 class
In 1930, the
Central Argentine Railway (Ferrocarril Central Argentino
or FCCA) ordered twenty large three-cylinder PS11 class Pacific
Caprotti valve gear , which were at the time the most
powerful locomotives on the FCCA. In 1939, one of these set up a South
American speed record, averaging 65.7 miles per hour (105.7 kilometres
per hour) on the El Cordobes express across the 188 miles (303
kilometres) non-stop run from
The Vulcan Foundry built a further fifty locomotives of a modernised PS12 class version of this design for the nationalised Ferrocarriles Argentinos (FCA) between 1950 and 1953.
In Australia, the first known example of the wheel arrangement was the Q class tank locomotive of the 3 ft 6 in (1,067 mm) gauge Western Australian Government Railways (WAGR). The six 4-6-2T locomotives were introduced in 1896, but four of them were soon converted to a 4-6-4T Hudson configuration.
The WAGR was the largest user of Pacific tender types in Australia.
In total, the WAGR operated at least 223
* The first simple expansion (simplex)
Western Australian Government Railways P class no. 508
* It was not until the introduction of the WAGR P class in 1924 that
The 3 ft 6 in (1,067 mm) Midland Railway of
In the 1920s, heavy Pacific locomotives were introduced by both South Australian Railways (SAR) and Victorian Railways (VR), in response to increasingly heavy passenger trains and the demand for faster services. Although similar in size, power and top speed, their designs reflected different approaches.
* The SAR 600 class reflected contemporary American locomotive practice, both in design features and appearance, with two large 24 by 28 inches (610 by 711 millimetres) cylinders. The SAR owned altogether twenty Pacific locomotives, of which the first ten were of the 600 class, supplied by Armstrong Whitworth of the United Kingdom in 1922. The remainder were of the 620 class , built at Islington Workshops between 1936 and 1938.
Victorian Railways S class
* The VR S class , on the other hand, showed a strong British London and North Eastern Railway influence, with three 20 1⁄2 by 28 inches (521 by 711 millimetres) cylinders and with Gresley conjugated valve gear driving the third inside cylinder. The VR’s four S class locomotives were built at Newport Works between 1928 and 1930.
Victorian Railways Dde class , c. 1910
The VR also built a 4-6-2T locomotive class, the Dde class that was
developed from a successful Dd class 4-6-0T design in 1908, intended
for outer suburban passenger services in
The 3 ft 6 in (1,067 mm) gauge
New South Wales Government Railways (NSWGR) introduced its C38
class for express passenger service in 1943. These two-cylinder
Pacifics had a free-steaming 245 pounds per square inch (1,690
kilopascals) boiler and were renowned for their performance. Retired
class leader no. 3801 has achieved considerable fame in preservation,
with notable feats such as a transcontinental journey from
Tasmanian Government Railways
ČSD no. 354.195, a Czechoslovakian version of the Austrian class 629
The only Pacific type to be built in Austria was the class 629 4-6-2
tank locomotive of the
Imperial Royal Austrian State Railways
The class 629 was later also produced and developed in Czechoslovakia
as the class 354.1 of the
Czechoslovak State Railways (ČSD). Between
1921 and 1941, 219 of these locomotives were built there and, in
addition, seventeen of the original Austrian class 629 locomotives
were used there. They survived in service until 1978. Three examples
have been preserved. (Also see
The Pacific tender locomotives that worked passenger services in
Austria between 1938 and 1945 all belonged to the railways of other
countries, such as the
Bulgarian State Railways
In 1938, BDZ improved its express service between
Canadian Pacific G3c class no. 2317
Canadian Pacific Railway
First World War
102 examples of the G5 class locomotive were built after 1944. The
first two were built by Angus and the rest by Montreal and the
Canadian Locomotive Company
The Reid-Newfoundland Company Limited, which operated the railways in Newfoundland , took delivery of ten Pacific locomotives with 42 inches (1,067 millimetres) drivers between 1920 and 1929, built by Baldwin, Montreal and ALCO Schenectady. Numbered 190 to 199, they had two 18 by 24 inches (457 by 610 millimetres) cylinders and weighed 56.3 tons. They all passed to the Government-owned Newfoundland Railway, and then to Canadian National Railways (CN) when Newfoundland joined the Confederation of Canada . CN renumbered them 591 to 599 and classified them as J-8-a (BLW 54398–54401 and 54466–54467 of 1920), J-8-b (BLW 59531 and MLW 67129, both of 1926) and J-8-c (ALCO-Schenectady 67941–67942 of 1929).
They were the only Pacific type locomotives built to operate on 3 ft 6 in (1,067 mm) gauge in North America. The only surviving Newfoundland steam locomotive, the Newfoundland Railway no. 193, later CN no. 593, is preserved and on display at the Humbermouth Historic Train Site in Newfoundland. (Also see Mexico )
The Japanese introduced several classes of Pacific locomotive during their occupation of Manchuria, but the Pashiro became the standard and was China's most numerous class of steam passenger locomotive. Between 1933 and 1944, around 272 were built for the South Manchuria Railway (SMR), the Manchurian National Railway and the railways of occupied North China. They were built by various Japanese builders, including Dalian and Sifang , while the SMR’s own workshops were also involved in the construction.
The Japanese-built Pashina locomotives were used on the Asia Express train between 1934 and 1943, during Japanese control of the SMR. These were built by Kawasaki and Dalian. Chinese National Railway RM Class No. 1163 at Central Park, Aioi, Hyogo
The name Shengli (Victory) was used for all classes of Pacific inherited by the new China in 1951. The Pashiro became the Shengli 6 (SL6 class), while the Pashina locomotives were designated Shengli 7 (SL7 class) under Chinese ownership.
The Sifang works resumed production of SL6 class locomotives in 1956 and completed 151 locomotives before moving on to RM class construction in 1958. The inability of the class to haul the heavier passenger trains that were introduced in the 1970s and 1980s, saw them progressively being re-allocated to secondary duties. By 1990, most of the survivors were concentrated in Manchuria at the Dashiqiao, Jilin and Baicheng depots.
The RM class was China's last steam passenger design. It was a late 1950s development of the successful pre-war SL6 class Pacific and became the standard passenger class. The class, numbered RM 1001 to 1258, entered service in 1958 and a total of 258 were built before production ceased in 1966. In the 1970s, they were gradually displaced from premier services by locomotives more suited to handling heavier trains and they ended their service lives on secondary passenger duties.
Czechoslovakian 387.043 at the Lužná u Rakovníka Museum
Between 1926 and 1967, two Pacific tender locomotive classes were
The 2100 horsepower Pacific Class 387.0 was the most successful of
these, nicknamed Mikádo because of its short chimney. Between 1926
and 1937, 43 were built in five series by the
Škoda Works in
Prior to 1954, the
Egyptian State Railways used 4-4-2 Atlantic or
4-6-0 Ten-wheeler types on express passenger trains. However, in 1953
a requirement arose for a locomotive capable of hauling 550-tonne
trains over the 150 kilometres (93 miles) from
They were ordered from Société Alsacienne (SACM) at Grafenstaden in
France. The class was unusual in being designed for oil burning, with
a long narrow firebox and combustion chamber fitted between the plate
frames. They had a short lifespan in express train service, since the
1956 war put an end to fast train running in Egypt. The Pacifics were
then transferred to haul slower night express trains to
The French-owned Imperial Railway Company of
The first one was bought from Forges, Usines et Fonderies de
Haine-Saint-Pierre in Belgium in 1923. This locomotive had been
ordered by the Spanish railway Ferrocarril Madrid-Aragon in 1914,
prior to the outbreak of the
First World War
Three more similar Pacific locomotives, but superheated , were
ordered in 1936. They arrived after the Italian conquest of Ethiopia
and were allocated to the
Addis Abeba and
Twenty-two Pacific locomotives of the Class Hr1 , numbers 1000 to 1021 and named Ukko-Pekka after the nickname of Finnish President Pehr Evind Svinhufvud , were constructed in Finland by Tampella and Lokomo between 1937 and 1957. They were the largest passenger locomotives to be built and used in Finland and remained the primary locomotives on express trains for Southern Finland until 1963, when the class Hr12 diesel locomotives took over. A Finnish "Ukko-Pekka" class Hr1
The last two Class Hr1 locomotives to be built in 1957, numbers 1020
When tested after delivery from
By European standards, Class Hr1 locomotives ran high annual
kilometre figures, between 125,000 and 140,000 kilometres (78,000 and
87,000 miles) per locomotive per year between 1937 and 1963. The two
fully roller bearing-equipped locomotives even exceeded the 150,000
kilometres (93,000 miles) mark in 1961, the highest annual kilometre
figure to be obtained by a steam locomotive in Northern Europe. The
only similar annual kilometres by European Pacific type locomotives
were run in
At least twelve class Hr1 locomotives were preserved as at April 2008, of which two were in operational condition. These were no. 1021, owned by the VR Group , and the privately owned no. 1009. No. 1001 was reserved for the Railway Museum in Hyvinkää and no. 1002 was reserved for the city of Helsinki as a possible static monument.
France was a major user of the
The Paris à Orléans ordered a further 98 Pacific locomotives that
were delivered between 1908 and 1910, and another 89 in 1909 and 1910.
Another fifty were ordered from the
American Locomotive Company
The L\'Ouest followed with two prototype
The Alsace-Lorraine built eight Pacific locomotives in 1909, at the time when the railway was still under German control. These became French locomotives in 1920.
The Paris à Lyon et à la Méditerranée (PLM) was the largest French user of Pacific locomotives, owning 462, built between 1909 and 1932. These were both compound and simplex locomotives and were built both with and without superheaters . Large numbers were later rebuilt to compounds or to incorporate superheaters by both the PLM and the state-owned Société Nationale des Chemins de fer Français (SNCF). Nord E 41 at St-Pierre-des-Corps
The Nord built 139 Pacific locomotives from 1912, including the various so-called Superpacific types of 1923 to 1931. The company also ordered Chapelon type rebuilds from the Paris à Orléans in 1934, and new-built locomotives between 1936 and 1938. L\'État 231 G Ouest no. 558, preserved by the Pacific Vapeur Club
The L\'État owned 352 Pacific locomotives, some of which were transferred from the Bavarian Railways and Württemberg Railways as Armistice reparations in 1918.
The Midi likewise owned altogether forty Pacific locomotives, acquired in three batches.
The eastern L\'Est never built a 4-6-2, preferring its 4-6-0
Ten-wheeler types until it progressed straight to the much larger
After nationalisation in 1938, the SNCF built no more Pacifics, although it continued to rebuild some of the existing stock running on lines already established by the private railway companies, particularly by continuing to apply the great improvements brought about by the work of André Chapelon .
Grand Duchy of Baden State Railways Class IVf
The first Pacific locomotive for a German railway was the Badische
IVf class for the
Grand Duchy of Baden State Railways (Großherzoglich
Badische Staatseisenbahnen), designed by Maffei in 1905. However, due
to manufacturing delays, the first three locomotives were not
introduced until 1907, shortly after the first French Pacifics. They
were four-cylinder compound locomotives of the Von Borries type. After
the Maffei locomotives, a further 32 were built under license by
Karlsruhe Engineering Works and delivered between 1907 and 1913.
Bavarian S 3/6
However, the most successful early German Pacific class was the
Bavarian S 3/6
When the various pre-
First World War
During the 1920s and 1930s the
* The Class 01 , a two-cylinder standard type of the Deutsche
Reichsbahn introduced between 1926 and 1938, was the first
standardised steam express passenger locomotive class to be built for
the unified German railway system.
* The Class 02 four-cylinder compound locomotive version was less
successful, being costly to maintain. Only ten were built and all of
them were rebuilt into two-cylinder 01 class locomotives between 1937
* The Class 03 was a lighter version of the 01 class, built between
1930 and 1938. Ten locomotives of the 03.10 class remained in Poland
Second World War
The Hungarian locomotive builder
MÁVAG (Magyar Királyi
Államvasutak Gépgyára) built several classes of
The earliest Indian
Indian XB class of 1927
In 1924, the Locomotive Standards Committee of the Indian Government recommended eight basic types of locomotive for use on the sub-continent, three of which were 4-6-2s. These were the XA class for branch line passenger working, the XB class for light passenger trains and the XC class for heavy passenger trains. The Vulcan Foundry built large numbers of all these classes for the different Indian railways between the late 1920s and early 1930s, beginning with fourteen each for the East Indian Railway Company (EIR) and the Great Indian Peninsula Railway (GIPR) in 1927.
In 1937, two XP class locomotives were built for the GIPR by Vulcan
Foundry. These were experimental locomotives that formed the basis for
India's renowned WP class , designed by Railway Board designers in
India specifically to use low-calorie, high-ash Indian coal. The WP
class was introduced after the
Second World War
There were also two WL classes. The first four locomotives, built in 1939 by Vulcan Foundry for the North Western Railway , went to Pakistan upon the India-Pakistan partition . A second Indian WL class was introduced in 1955 and ten of these locomotives were built by Vulcan Foundry.
The Bengal Nagpur Railway had a saturated C class, a superheated CS class, and a CC class comprising C class locomotives that had been converted from saturated to superheated steam. SIR class YB 4-6-2 of 1928
The South India Railway (SIR) ordered six YB class and two XB class Pacific locomotives from the Vulcan Foundry in 1928.
The earliest Pacific classes in
Twenty class C53 locomotives were delivered to the Staatsspoorwegen
in 1917 and 1922. They were designed by Dutch engineers and were
manufactured in the
The majority of the class were scrapped by the Indonesian Railway
soon after Indonesia’s independence. The last survivor was number
C5317, which lasted until the final days of steam locomotives in
When the 4 ft 8 1⁄2 in (1,435 mm) standard gauge
Three were delivered in 1941 and designated the PC class , but the fourth was lost en route. When the Iraqi standard gauge railways were dieselised in the 1960s, the class was withdrawn from service.
Italian Class 691 no. 022 at
Between 1911 and 1914, 33 Pacific locomotives of the 690 class were
built for the
Ferrovie dello Stato Italiane (Italian State Railways),
twenty by Breda in
Between 1928 and 1931, these locomotives were rebuilt with larger boilers and reclassified as Class 691. One of them, no. 691.011, established the Italian speed record for steam locomotives at 150 kilometres per hour (93 miles per hour).
The whole class was withdrawn between 1962 and 1963. One locomotive, no. 691.022, has been preserved at the Museo della Scienza e della Tecnologia di Milano (National Museum of Science and Technology of Milan).
Japanese Government Railways
Japanese Government Railways
Other Japanese Pacific designs included the C52 class, built from 1926 to 1929, the C53 and C54 classes that were both built in 1935, the C55 class, the C57 class built from 1937 to 1953, and the C59 class.
The C57 Class, of which 135 were built by Kawasaki , Kisha Seizō,
The 3 ft 6 in (1,067 mm)
The 1,000 mm (3 ft 3 3⁄8 in) metre gauge Malayan Railway was amongst the earliest railways in Asia to adopt Pacific type locomotives. Sixty locomotives of the Federated Malay States Railways (FMSR) Class H were built between 1907 and 1914. With a small volume of highly rated freight traffic, it was possible to adopt standard engines for both passenger and freight services. Three coupled axles were sufficient to move the trains at moderate speeds over the whole Malayan rail network.
As a result of experience gained with the first batch of 4-6-2 locomotives, the design of Malayan Pacific locomotives was finalised and 68 engines of this design were eventually built. They had bar frames, steel fireboxes and three cylinders, each of 13 by 24 inches (330 by 610 millimetres). The coupled wheels were 54 inches (1,372 millimetres) in diameter. The heating surface of the boiler was 1,109 square feet (103 square metres), of which 218 square feet (20.3 square metres) was superheating surface, while the grate area was 27 square feet (2.5 square metres). The total weight in working order was 60.5 tons, with a maximum axle load of 12.9 tons. Its maximum speed in ordinary service was 50 miles per hour (80 kilometres per hour). The three cylinders were provided with rotary cam poppet valves with the camshaft divided into two parts, independently driven from each side of the engine, which avoided complete immobilisation in case of a breakdown on a long stretch of single track. These locomotives were all later converted to burn oil fuel.
During the Second World War, after the fall of
After the arrival of the mainline diesel-electric locomotives in the latter part of the 1950s, the Pacifics were transferred to less important trains. Many survived up the end of Malayan steam traction in the 1970s.
Canadian National Railway
The Caminhos de Ferro de Lourenço Marques in Portuguese Mozambique
ordered its first three class 300 Pacific locomotives from Baldwin in
1919. They hauled passenger trains on the 88 kilometres (55 miles)
line between Lourenço Marques (Maputo) and
Ressano Garcia , and also
crossed the South African border at
Komatipoort in South Africa, 93
kilometres (58 miles) from Lourenço Marques, where South African
Railways locomotives took over for the rest of the way to
The first true Pacifics, the original thirteen Q class 4-6-2 locomotives built by Baldwin for the New Zealand Railways Department (NZR) in 1901, worked until withdrawal in 1957. None has been preserved.
The most notable
In 1960 Ted Blomfield, locomotive fitter at Rotorua, New Zealand, built a Super Q Pacific for the 1 foot gauge Toot and Whistle Railway. The engine operated at Toot and Whistle's Kuirau park railway for six years before officialdom demanded the locomotive be retired. It was replaced by a Black Five replica. Another Super Q exists as a 5 inch-gauge engine.
Between 1926 and 1928, the 3 ft 6 in (1,067 mm) gauge Nigerian
Railways ordered ten Class 405 Pacifics from Nasmyth, Wilson ">
Pm36-2 Beautiful Helene in
PKP class Pm36
The Pm36-1 won a gold medal at the International Exposition of Modern
Art and Technology in Paris in 1937. It was damaged and later scrapped
Second World War
Besides these two Polish-built locomotives, several German DRG class
03, class 0310 and class 181 locomotives (ex Württemberg Class C )
and Austrian class 629 tank locomotives saw service in Poland as the
classes Pm2, Pm3, Om101 and OKm11 respectively. (Also see
One 600 mm (1 ft 11 5⁄8 in) narrow gauge Pacific locomotive, the Belgijka , built in 1935 by Ateliers Métallurgiques in Nivelles and Tubize in Belgium, was also used in Poland and is preserved at the Narrow Gauge Railway Museum in Wenecja , Poland.
The Portuguese Railways (Caminhos de Ferro Portugueses or CP) had two
batches of Pacific 2C1-h2 class locomotives running on its 1,668 mm (5
ft 5 21⁄32 in) broad gauge lines, built by
The first use of the
In 1901, the NGR rebuilt one of its Class K"> Ex NGR Class Hendrie A, SAR Class 2
* In 1905, two Class A Pacific tender locomotives entered service on
the NGR, designed by Locomotive Superintendent D.A. Hendrie and built
by NBL. They had plate frames, used saturated steam and had Stephenson
valve gear . To accommodate the wide and deep firebox, Hendrie used a
bridle casting similar to that introduced on the CGR by Beatty with
his Class 6
2-6-2 Prairie in 1903. This method of widening the frames
for the firebox continued in South African locomotive design until
1927, when the general adoption of bar frames rendered it no longer
necessary. In 1912, they were designated Class 2 on the SAR.
* In addition, two more Class A locomotives, also known as Class
Hendrie C, were built in the NGR’s
Cape Government Railways
The first locomotives with a Pacific wheel arrangement in the Cape
were two tank locomotives that entered service in 1896 on the private
Metropolitan and Suburban Railway that operated a suburban passenger
* In 1903, the first two
Karoo locomotives entered passenger service
on the CGR. It was a development of the CGR Class 6
2-6-2 and was
designed by Chief Locomotive Superintendent H.M. Beatty. The
locomotives, built by
Kitson and Company , were acquired to cope with
the increasing weight of passenger trains on the one in eighty ruling
Beaufort West and
De Aar in the
Karoo , hence the
Karoo Class name. In 1912, when they came onto the SAR roster, they
were designated Class 5A .
* Following on the success of the first two
Karoo Class locomotives,
a further four were ordered from
Beyer, Peacock and Company in 1904.
They were modified slightly in view of the experience gained with the
original two. On the SAR, they were all designated Class 5B , until
one was later reboilered with a Watson Standard no. 1 boiler and
reclassified Class 5BR. All of them were later equipped with piston
valve cylinders and superheaters.
* In 1907, the CGR placed a single experimental three-cylinder
compound Pacific in service, based on the second
Karoo Class . Built
North British Locomotive Company (NBL), it was not classified
and was simply referred to as the Three Cylinder Compound. The
cylinders were arranged in the Smith system of compounding, with a
single high-pressure cylinder situated between the two low-pressure
cylinders. The locomotive had a bar frame ,
Walschaerts valve gear and
used saturated steam. Compared to a simplex two-cylinder Karoo, the
compound could take a heavy train up a long continuous grade at a much
higher speed, while experienced drivers found it could outperform the
Karoo in terms of power as well as fuel and water consumption. In
1912, the SAR classified it as Class Experimental 1 .
* The Enlarged Karoo, built by
Vulcan Foundry , was one of the
locomotive types that were designed and ordered by the CGR before the
SAR was established and that ended up being delivered to the newly
established national railways of the
Union of South Africa
Central South African Railways
CSAR Class 9 no. 600 , SAR no. 727
Five Class 9 Pacific passenger locomotives, designed by P.A. Hyde,
the first Chief Locomotive Superintendent of the Central South African
Railways (CSAR), were delivered from
Vulcan Foundry in 1904. They had
Stephenson valve gear
Five Class 10 variants were introduced between 1904 and 1910.
* Also in 1904 and also designed by Hyde, fifteen Class 10 Pacific locomotives were delivered to the CSAR from NBL. The locomotives were of an extremely advanced design, superheated and with the highest boiler pitch yet in South Africa, with plate frames, wide Belpaire fireboxes , outside admission piston valves and Walschaerts valve gear . In 1912, when they were assimilated into the SAR, they retained their Class 10 classification. * Ten heavy Pacific passenger locomotives, designed by CSAR Chief Mechanical Engineer (CME) G.G. Elliot based on Hyde’s Class 10 design, were ordered from NBL and delivered in 1910. They had plate frames , Belpaire fireboxes and Walschaerts valve gear and were delivered in two variants, five of them using saturated steam while the rest were superheated. While similar to the Class 10, their boilers were arranged further forwards, their firebox throats and back plates were sloped instead of being vertical, they used inside admission piston valves and their valve gear was reversed by means of a vertical steam reversing engine mounted on the right-hand running board. They were all classified as Class 10-2 by the CSAR but, in 1912, the SAR designated the saturated steam locomotives Class 10A and the superheated ones Class 10B . A further five superheated Class 10B locomotives were delivered to the SAR from Beyer, Peacock in 1912. * Twelve light Pacific locomotives were also placed in service by the CSAR in 1910, classified as Class 10-C. Designed by Elliot and built by NBL, they were similar to the Class 10-2, but slightly smaller and with smaller coupled wheels. They used saturated steam and had Belpaire fireboxes and Walschaerts valve gear , but they were soon reboilered and equipped with superheaters. In 1912 they were designated Class 10C by the SAR. * One more Pacific was ordered by the CSAR from ALCO in 1910. It was superheated and built to very much the same specifications as that of the Class 10-2 of that same year, but with a bar frame. It was slightly more powerful than the Class 10-2 and was designated Class 10 by the CSAR, along with the fifteen locomotives of 1904. In 1912, the locomotive became the sole Class 10D on the SAR.
South African Railways
Seven Class 16 variants were introduced on the South African Railways (SAR) between 1914 and 1935. SAR Class 16 no. 800 , c. 1930
* The Class 16 Pacific was designed by Hendrie, CME of the SAR from
1910 to 1922, and was built by NBL, who delivered twelve locomotives
in 1914. The design closely followed that of the Class 15 4-8-2
Mountain type that was introduced at the same time from the same
builders, and many parts were made interchangeable. They had
Walschaerts valve gear , were superheated and had Belpaire fireboxes .
At the time, it was considered a very large and powerful express
locomotive, even when compared to British locomotives built to run on
4 ft 8 1⁄2 in (1,435 mm) standard gauge . With 60 inches (1,524
millimetres) coupled wheels, the ratio of wheel diameter to rail gauge
was the same as that of a
Standard gauge locomotive having 81 inches
(2,057 millimetres) coupled wheels. Their tractive effort of 29,890
pounds-force (133.0 kilonewtons) at 75% boiler pressure exceeded the
27,800 pounds-force (123.7 kilonewtons) at 85% boiler pressure of
Churchward’s The Great Bear on the
Great Western Railway and
equalled, also at 85% boiler pressure, that of Gresley’s subsequent
Great Northern Pacifics. This made the Class 16 the most powerful
express passenger locomotive design yet to have been built in Britain
at the time.
* The Class 16A four-cylinder simplex Pacific of 1915 was designed
by Hendrie and built by NBL. Two locomotives were delivered, identical
in most respects to their predecessor Class 16 except that they had
four cylinders instead of the usual two. All four cylinders were
arranged in line below the smokebox and were the same size, with the
outer cylinders driving the centre coupled wheels while the inner
cylinders operated on a cranked leading coupled wheel axle. The result
was a very smooth running locomotive, capable of very fast running,
but since the available space on a
Class 16B No. 805 restored to its as-delivered appearance
* The Class 16B Pacific, also designed by Hendrie, was also built by NBL, who delivered ten locomotives in November 1917. They were identical to the predecessor Class 16 and successor Class 16C in most respects, except that they had wider cabs than the Class 16, while the Class 16C had a combustion chamber in the firebox. All ten were eventually reboilered with Watson Standard no 2B boilers and Watson cabs with slanted fronts, and reclassified to Class 16CR. * Ten Class 16C locomotives, also designed by Hendrie and built by NBL, were delivered in 1919 with another twenty following in 1922. Identical to predecessors Class 16 and Class 16B in most respects except for the addition of a combustion chamber, they proved to be excellent free-steaming, fast and reliable locomotives with a reserve of power greater than either of the predecessors. All thirty were later reboilered with Watson Standard no 2B boilers and also reclassified to Class 16CR.
Class 16D no. 860
* Seven Class 16D Pacific locomotives were built for the SAR by
Baldwin Locomotive Works
Henschel-built Class 16DA of 1930
* When A.G. Watson succeeded Collins as CME in 1929, he designed a
boiler with a very wide firebox of the Wootten type, with a grate area
of 60 square feet (5.574 square metres) to improve the steaming
properties of these locomotives. The grate was 15 square feet (1.394
square metres) larger than that of the Hohenzollern and Baldwin
locomotives and these boilers were installed on the final six Class
16DA locomotives, built by
Class 16E No. 858
* The Class 16E Pacific was designed by Watson and built by
Henschel, who delivered six locomotives in 1935. With its 72 inches
(1,829 millimetres) diameter coupled wheels, it was considered to be
the most remarkable
In 1906, two small
In 1907, the NGR placed another six 4-6-2T tank locomotives in
service, designed by Hendrie based on his
In 1908, two Pacific tank locomotives with bar frames and Walschaerts valve gear , built by Bagnall , entered service on the narrow gauge Walmer Branch of the CGR in Port Elizabeth. They came onto the SAR roster in 1912 and remained in service until the Walmer branch was closed in 1929.
In 1911, shortly before being amalgamated into the SAR, the NGR
placed the first two of seven 4-6-2T narrow gauge locomotives in
service, built by
Kerr, Stuart and Company
In 1916, the SAR ordered six narrow gauge Pacific tender locomotives
Baldwin Locomotive Works
A Pacific locomotive was ordered by the Ferrocarril Madrid-Aragon
from Forges, Usines et Fonderies de Haine-Saint-Pierre in Belgium in
1914, but was not delivered, presumably due to the disruption to trade
caused by the
First World War
In 1958, the Ferrocarril La Robla purchased four vintage 1,000 mm (3 ft 3 3⁄8 in) metre gauge Pacific locomotives from the Tunisian Railways . These had been built in 1914 by Société Alsacienne de Constructions Mécaniques (SACM). They were numbered 181 to 185 and were scrapped in the early 1970s after having served in Spain for more than ten years. (Also see Tunisia )
SJ Class F
In 1913, the Swedish State Railways (Statens Järnvägar or SJ) ordered eleven four-cylinder compound Pacific type locomotives from Nydqvist ">
In 1935, five more locomotives of the Japanese Government Railways Class 55 were added, numbered 551 to 555, and in 1938 four more were delivered, numbered 556 to 559.
The Royal State Railways of Siam (RSR), the predecessor of the State
The final type of Pacific steam locomotive was when RSR imported the
parts for 10 locomotives, based on the
Second World War
In 1914, the Tunisian Chemins de fer Bône-Guelma placed five 4 ft 8
1⁄2 in (1,435 mm) standard gauge Pacific locomotives in service at
They hauled all principal express and passenger trains between Tunis Ville and Ghardimaou until 1951, when the new mainline diesels relegated them to secondary trains. All were withdrawn from service during 1954 and 1955.
Also in 1914, the Chemins de fer Bône-Guelma ordered five 1,000 mm (3 ft 3 3⁄8 in) metre gauge locomotives from SACM. The engine weight in working order was 56.6 metric tonnes, with coupled wheels of 1,500 millimetres (59 inches) diameter and two 465 by 610 millimetres (18.3 by 24.0 inches) cylinders.
They were considered very successful and
GWR no.111, The Great Bear
Prior to the 1923 Grouping , only five
The Great Northern Railway (GNR) and the North Eastern Railway (NER) each built two Pacific types in 1922, later to become the Classes A1/A3 and A2 on the London and North Eastern Railway (LNER). Further examples of these two classes were built by the LNER after 1923. LNER Class A3 4472, the Flying Scotsman
The GNR Class A1 , designed by Sir
Nigel Gresley and later rebuilt
into the improved Class A3, featured three cylinders and an innovative
conjugated valve gear . The class eventually consisted of 79
locomotives. After initial teething problems, it proved to be an
excellent design and one of them, the Flying Scotsman , was the first
British locomotive to be officially recorded as reaching 100 miles per
hour (160 kilometres per hour). The
LNER Class A4
This speed was surpassed by the streamlined
LNER Class A4
A further 89 Pacific locomotives of the Peppercorn Class A1 ,
Thompson Class A1/1 , Peppercorn Class A2 , Thompson Class A2/1 ,
Thompson Class A2/2 and Thompson Class A2/3 were either built or
rebuilt for the LNER by Edward Thompson and
Arthur Peppercorn ,
although many actually only appeared in the
The London, Midland and Scottish Railway (LMS) introduced its twelve Princess Royal Class Pacific locomotives in 1933 and then enlarged the design with the streamlined Princess Coronation Class of 1937. 37 locomotives of the Coronation Class were built by 1947, with one more appearing in 1948 in the BR era. Coronation no. 6220 , the first of the class, reached 114 miles per hour (183 kilometres per hour) on 29 June 1937 and briefly held the British speed record for steam traction, until it was bettered by the LNER Mallard a year later. The LMS Princess Royal Class was also used as the basis for an unusual experimental locomotive, the Turbomotive , which used turbines instead of cylinders. Battle of Britain class no. 34072 257 Squadron
During the Second World War, the Southern Railway (SR) introduced two classes of Pacific, designed by New Zealander Oliver Bulleid . These were the Merchant Navy Class and the West Country and Battle of Britain Class . These two classes continued to be built in the BR era and eventually totaled thirty Merchant Navy Class locomotives and 110 West Country and Battle of Britain Class locomotives.
The 55 BR Standard Class 7 Britannia Pacific locomotives, introduced in 1951, were of a simple expansion two-cylinder design with Walschaerts valve gear . Their conservative design reflected a requirement for a more cost-effective, lower maintenance locomotive. Ten locomotives of a lighter version, the BR Standard Class 6 , were introduced in 1952. BR standard class 8 Duke of Gloucester
The final Pacific design in the United Kingdom was the BR Standard Class 8 no. 71000 Duke of Gloucester , of which only one was built in 1954. It had many parts in common with the Britannias, but had three cylinders and Caprotti valve gear . It was used as a test-bed of sorts to be further developed with improved efficiency and power as the stated goal.
In the same year, the
NER Class Y
In 1911, the PRR ordered an experimental K-29 class
The last PRR Pacific locomotives were two large K-5 class
locomotives, built in 1929. No. 5698 was built at the PRR Altoona
Works and had
Walschaerts valve gear , while no. 5699 was built by
Baldwin and had
Caprotti valve gear . Although successful, these
locomotives were not replicated, since the larger
The first modern example of the type to be built for duty in the United States, was built for the Missouri Pacific in 1902, but the chief proponent of the type west of the Mississippi River was the Atchison, Topeka and Santa Fe Railway, who began buying the type the next year and ultimately owned 274. The road would have pioneered the type, if not for a belief that a two-wheeled lead truck would be sufficient for high speed passenger service. They began buying 2-6-2 Prairie types in quantity from Baldwin in 1901, with the four cylinder Vauclain compound system, a weight of 190,000 pounds (86,183 kilograms) and 79 inches (2,007 millimetres) diameter coupled wheels.
When these proved insufficiently stable for high speed service, the
road ordered the 1200 class of
The Santa Fe ordered additional Pacific types of both four cylinder balanced compound and two cylinder simple types in seven classes through 1914. These gradually increased to 276,500 pounds (125,418 kilograms) and invariably rode on 73 inches (1,854 millimetres) drivers. The simple types tended to run conservative pressures at 170 to 175 pounds per square inch (1,170 to 1,210 kilopascals), while the compounds ran at 220 to 175 pounds per square inch (1,520 to 1,210 kilopascals). The early examples utilized a firebox grate of 54 square feet (5 sq. m), but the last few classes had larger grates of 57.6 sq. ft. (5.35 sq. m). All of these were considered light Pacifics by the road, and there were a few engines of orphan classes as well. Some of these were scrapped as compounds, but most were rebuilt with two 23½" X 28" (597 x 711 mm) simple cylinders and 220 pounds per square inch (1,500 kilopascals) operating pressure.
The railroad began scrapping these in 1932, and regretted scrapping
those few during the massive traffic of the Second World War. Two were
semi-streamlined for a brief period during 1939. They hauled all
manner of passenger trains, and saw occasional duty in local freight
and helper service. All were out of service by 1955. They initially
served on the western portion of the Santa Fe system, west of La
Junta, Colorado, where the line traversed the Rocky Mountains and
tackled the mountains of California. 4-4-2 Atlantic types were
generally used on the Great Plains. Later, as passenger cars grew to
85 feet (26m) in length and gained weight due to all-steel
construction, Pacifics would replace the Atlantic types in the east
and the western stretches would be served by new
These engines were not dissimilar to the USRA Light Pacifics introduced during the First World War, but differed in certain respects. The Santa Fe, like most large United States railroads, was accustomed to custom-designing their own power and refused to buy USRA designs during the ill-fated nationalization of the United States railroads under Wilson. This era, however, did allow many smaller railroads, who could not afford to custom-design power, to modernize their fleets and it also saw the rise of the USRA Heavy Pacific. The Pennsylvania K-series served as a prototype for these, but they differed in important aspects such as the PRR's Belpaire fireboxes.
The Santa Fe did not buy any USRA Heavy Pacifics, either, but after the war, Baldwin began building the new and even heavier 3400 Class for the road. These were huge at 288,000 to 310,350 pounds (130,635 to 140,772 kilograms), but were otherwise a conservative design with two simple 25 x 28 cylinders, Walschaerts valve gear , 66.8 square feet (6.2 sq m) of grate and 200 pounds per square inch (1,400 kilopascals) boilers. Fifty were built by Baldwin through 1924 but, while improvements to the light Pacifics were mostly confined to simplification and other updates were only sporadically applied, all of the 3400s were built or retrofitted with feedwater heaters and all but six were to receive 79 inches (2,007 millimetres) diameter driving wheels before or during the Second World War. All got a pressure increase to 220 pounds per square inch (1,500 kilopascals), nine received thermic syphons, and a little experimentation was done with combustion chambers and roller bearings. Weights ultimately reached 312,000 to 326,000 pounds (141,521 to 147,871 kilograms). These, too, were mostly out of service by 1955. Six Santa Fe Pacific types survive, most of them of the heavy 3400 Class. ALCO-built Soo Line 2719 at Two Harbors, Minnesota , 2009
Most of the United States railroads which offered passenger service, used Pacific types. Except for the custom design and sheer volume of units produced, the experience of railroads in the eastern and western United States was not dissimilar to that of the Pennsylvania and Santa Fe, respectively. Some roads developed these into the Hudson (or Baltic) type 4-6-4, others preferred the versatility of the 4-8-2 Mountain and 4-8-4 Northern types, and some, like the Santa Fe, bought both. One railroad, the St. Louis-San Francisco or Frisco, actually converted a few existing Pacific types to Hudsons with larger fireboxes in their Springfield shops. The Pacific type, however, was far and away the predominant passenger service steam engine in the United States until the end of steam. Lighter streamlined cars led to a resurgence of the light Pacific, with several railroads applying streamlined shrouds to older engines. The last Pacific built for service in the United States was delivered to the Reading in 1948. Most or all Pacifics were out of regular service by 1960.
One notable 4-6-2, the Soo Line no. 2719 which hauled the last of the Soo Line Railroad ’s steam-powered trains in 1959, was preserved and was restored to operating condition for excursions. She is now on display at the Lake Superior Railroad Museum in Duluth, Minnesota .
Wikimedia Commons has media related to
* ^ Railway Technical Web Pages (Steam Locomotive Glossary)
* ^ A B C D E F G H I J K L M N Holland, D.F. (1971). Steam
Locomotives of the South African Railways. 1: 1859–1910 (1st ed.).
Newton Abbott, Devon: David & Charles. pp. 69–77, 88–89,
101–103, 128–130, 137–139. ISBN 978-0-7153-5382-0 .
* ^ A B C D E Progress: Locomotive Development in New Zealand - The
"Pacific" Type. Its Genesis and Triumph. The New Zealand Railways
Magazine, Volume 9, Issue 7 (October 1, 1934).
* ^ A B C Steamlocomotive.com -
* v * t * e
SINGLE ENGINE TYPES
Divided drive and Duplex engine types
Fairlie , Meyer and
Articulated locomotives Mallet types (includes Triplex types )
* 2-1 0-10-2
* 2-10-10-10-1 0-10-2
Articulated locomotives Engerth types
* 0-4-4 * 0-4-6
* 0-8-4 * 0-8-6
* Shay * Climax * Heisler * Willamette
* Other notation forms: AAR * Swis