Under the Whyte notation

Whyte notation

The Whyte notation for classifying steam locomotives by wheel arrangement was devised by Frederick Methvan Whyte and came into use in the early twentieth century encouraged by an editorial in American Engineer and Railroad Journal...

 for the classification of steam locomotive

Steam locomotive

A steam locomotive is a railway locomotive that produces its power through a steam engine. These locomotives are fueled by burning some combustible material, usually coal, wood or oil, to produce steam in a boiler, which drives the steam engine...

s, 2-10-2 represents the wheel arrangement

Wheel arrangement

In rail transport, a wheel arrangement is a system of classifying the way in which wheels are distributed beneath a locomotive.. Several notations exist to describe the wheel assemblies of a locomotive by type, position, and connections, with the adopted notations varying by country...

 of two leading wheel

Leading wheel

The leading wheel or leading axle 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 in a truck...

s on one axle, usually in a leading truck, ten powered and coupled driving wheel

Driving wheel

On a steam locomotive, a driving wheel is a powered wheel which is driven by the locomotive's pistons...

s on five axles, and two trailing wheel

Trailing wheel

On a steam locomotive, a trailing wheel or trailing axle is generally an unpowered wheel or axle located behind the driving wheels. The axle of the trailing wheels was usually located on a trailing truck...

s on one axle, usually in a trailing truck. In the United States and elsewhere the is known as the Santa Fe type, after the Atchison, Topeka and Santa Fe Railway

Atchison, Topeka and Santa Fe Railway

The Atchison, Topeka and Santa Fe Railway , often abbreviated as Santa Fe, was one of the larger railroads in the United States. The company was first chartered in February 1859...

 that first used the type in 1903.

Other equivalent classifications are:

• UIC classification
  UIC classification
  The UIC classification of locomotive axle arrangements describes the wheel arrangement of locomotives, multiple units and trams. It is set out in the International Union of Railways "Leaflet 650 - Standard designation of axle arrangement on locomotives and multiple-unit sets". It is used in much...
  
  : 1E1 (also known as German classification and Italian classification)
  
• French classification: 151 (also known as Spanish classification
  Spanish classification
  With the Spanish classification system for locomotive wheel arrangements, the system for steam machines.- Steam :With steam locomotives, there are three digits normally and more with articulated locomotives...
  
  )
  
• Turkish classification
  Turkish classification
  In the Turkish classification system for railway locomotives, the number of powered axles are followed by the total number of axles. It is identical to the Swiss system except that the latter places a slash between the two numbers.Thus0-6-0 becomes 33...
  
  : 57
  
• Swiss classification: 5/7
  
• Russian classification: 1-5-1

Evolution

The 2-10-2 evolved from the ATSF 2-10-0

2-10-0

Under the Whyte notation for the classification of steam locomotives, 2-10-0 represents the wheel arrangement of two leading wheels on one axle, ten powered and coupled driving wheels on five axles, and no trailing wheels...

 Decapod. The ATSF’s existing 2-10-0 locomotives, used as pushers up Raton Pass

Raton Pass

Raton Pass is a mountain pass on the Santa Fe Trail along the Colorado-New Mexico border in the United States. Raton Pass is a federally designated National Historic Landmark...

, encountered problems reversing back down the grade for their next assignments. The 2-10-0s, being unable to track around curves at speed, had to run very slowly to avoid derailing. Consequently, the ATSF added a trailing wheel to the engines, allowing them to operate successfully in both directions.

These first 2-10-2 became the forerunners to the entire 2-10-2 fleets. Like all ten-coupled designs, the long rigid wheelbase of the driving wheels presented a problem on curves, requiring blind drivers, lateral motion device

Lateral motion device

Lateral motion devices permit the axles in some railroad locomotives to move sideways relative to the frame.-Purpose:The coupled driving wheels on steam locomotives were held in a straight line by the locomotive's frame...

s and much play on the outer axles. To limit this problem, plus the weight of the rods, the driving wheels were generally small, up to 64 inches (1,625.6 mm), which in turn generated the problem of insufficient counterweights.

There were two forms of 2-10-2, the 'heavy' locomotive and a 'light' version. The 2-10-2's inherent problem was the low speed restriction on the type, which was about 35 miles per hour (56.3 km/h). Further, the 2-10-2 had other inherent restrictions. The massive cylinders that were required on USA locomotives for high tractive effort had the result that no reasonable sized valves could admit and exhaust steam at a sufficient rate to permit fast running. In addition the 2-10-2, like the 2-6-2

2-6-2

Under the Whyte notation for the classification of steam locomotives, 2-6-2 represents the wheel arrangement of two leading wheels, six coupled driving wheels and two trailing wheels.Other equivalent classifications are:...

, had its main rod connected to the third axle, very near to the centre of gravity, which created a violent nosing action when operating at speed.

In the USA the peak of the 2-10-2 design limitations was reached in 1926, and was overcome with the advent of the superior 2-10-4 design.

History

2-10-2s were used in a number of countries around the world, including those in North America, Western Europe, China, the Soviet Union and South Africa.

North America

In North America the 2-10-2 was produced between 1914 and 1930, after which its limitations became apparent and larger locomotives were built. About 2,200 were built, including about 500 of the two USRA

United States Railroad Administration

The United States Railroad Administration was the name of the nationalized railroad system of the United States between 1917 and 1920. It was possibly the largest American experiment with nationalization, and was undertaken against a background of war emergency.- Background :On April 6, 1917, the...

 WWI

World War I

World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...

 standard designs. The heaviest 2-10-2s were the ten built by Baldwin for the Reading circa 1931, weighing 451000 pounds (204.6 t) engine only. The Illinois Central 2800-class rebuilds probably had the highest calculated tractive effort for any two-cylinder steam locomotive at 104000 pound-forces (462.6 kN), even though the weight on drivers was only 333000 pounds (151 t).

The Baltimore and Ohio placed its first order for a 2-10-2 with Baldwin in 1914 (No. 6000). From 1914 to 1956 these B&O engines bore numbers commencing with 6, hence their nickname 'big sixes'. Known as the S class, there were several variant sub-classes. The engines were heavy and powerful and they held off the diesel-electrics until 1951, when they gradually began to be withdrawn and were finally all scrapped by 1959.

Germany

Continental Europe saw a fair number of 2-10-2s, although the type was always less popular than 2-8-2

2-8-2

Under the Whyte notation for the classification of steam locomotives, 2-8-2 represents the wheel arrangement of two leading wheels on one axle , eight powered and coupled driving wheels on four axles, and two trailing wheels on one axle...

s and 2-10-0

2-10-0

Under the Whyte notation for the classification of steam locomotives, 2-10-0 represents the wheel arrangement of two leading wheels on one axle, ten powered and coupled driving wheels on five axles, and no trailing wheels...

s. A large number of European 2-10-2s were tank locomotive

Tank locomotive

A tank locomotive or tank engine is a steam locomotive that carries its water in one or more on-board water tanks, instead of pulling it behind it in a tender. It will most likely also have some kind of bunker to hold the fuel. There are several different types of tank locomotive dependent upon...

s, taking advantage of the symmetrical nature of the arrangement. Examples on the German railway systems included classes BR84

DRG Class 84

The German DRG Class 84s were standard goods train tank locomotives with the Deutsche Reichsbahn. A total of twelve engines were placed into service by the Reichsbahn between 1935 and 1937. The machines were given operating numbers 84 001–012...

 and BR85

DRG Class 85

The Class 85 was a German goods train tank engine and standard locomotive with the Deutsche Reichsbahn.- History :In 1931, the DRG ordered ten locomotives from the firm of Henschel that were taken into the fleet as numbers 85 001–010. The Class 85 was intended for hauling passenger and goods trains...

, both standard designs built in 1935 and 1937 respectively, and class BR95, built in 1922 by the Prussian State Railways. From 1936 the German railways built 28 3-cylinder 2-10-2 tender freight locomotives of class BR45

DRG Class 45

German Class 45 steam locomotives were standard locomotives designed by the Deutsche Reichsbahn for hauling goods trains.- History :...

, which were the largest steam locomotive

Steam locomotive

A steam locomotive is a railway locomotive that produces its power through a steam engine. These locomotives are fueled by burning some combustible material, usually coal, wood or oil, to produce steam in a boiler, which drives the steam engine...

s on the system.

Spain

In Spain, the 2-10-2 wheel arrangement had one series of 22 units. Initially ordered for the Norte Co., the RENFE kept the entire series on hand. Built between 1941 and 1944 in La Maquinista Terrestre y Marítima factory in Barcelona for hauling heavy coal trains, they were amongst the most powerful steam locomotives in Europe. They had three cylinders but used simple expansion and were known as "Santa Fe" locomotives.

South Africa

On Cape gauge

Cape gauge

Cape gauge is a track gauge of between the inside of the rail heads and is classified as narrow gauge. It has installations of around .The gauge was first used by Norwegian engineer Carl Abraham Pihl and the first line was opened in 1862.- Nomenclature :...

, this wheel arrangement was first used by the South African Railways

Rail transport in South Africa

Rail transport in South Africa is the most important element of the country's transport infrastructure. All major cities are connected by rail, and South Africa's railway system is the most highly developed in Africa...

 (SAR) in 1927. Two Class 18

South African Class 18 2-10-2

In December 1927 and January 1928 the South African Railways placed two Class 18 steam locomotives with a 2-10-2 wheel arrangement in service.-Manufacturer:The Class 18 2-10-2 steam locomotive was designed by Colonel F.R...

 steam locomotives, the most powerful non-articulated locomotives to see service on the SAR, were introduced on the line between Witbank

Witbank

Witbank , also known as eMalahleni is a city situated on the Highveld of Mpumalanga, South Africa, within the eMalahleni Local Municipality. The name Witbank is Afrikaans for White Ridge and is named after a white sandstone outcrop where wagon transport drivers rested...

 and Germiston in an attempt to ease problems that were being experienced with increasingly heavy coal trains. It was designed by Colonel F.R. Collins, Chief Mechanical Engineer of the SAR from 1922 to 1929, and built by Henschel and Son

Henschel & Son

Henschel & Son was a German company, situated in Kassel, best known during the 20th century as a maker of transportation equipment, including locomotives, trucks, buses and trolleybuses, and armoured fighting vehicles and weapons....

 in Germany. They were three cylinder locomotives, with their two outer cylinders using Walschaerts valve gear and the inner cylinder using Gresley conjugated valve gear

Gresley conjugated valve gear

The Gresley conjugated valve gear is a valve gear for steam locomotives designed by Sir Nigel Gresley, chief mechanical engineer of the LNER, assisted by Harold Holcroft...

 that was actuated by the motions of the outer cylinders.

One more 2-10-2 locomotive, the Class 20

South African Class 20 2-10-2

In 1935 the South African Railways placed one Class 20 steam locomotive with a Santa Fe wheel arrangement in service. In 1950 it was modified to an experimental condensing locomotive.-Design:...

, was designed by A.G. Watson, Chief Mechanical Engineer from 1929 to 1936, and built by the SAR at its Koedoespoort shops in Pretoria

Pretoria

Pretoria is a city located in the northern part of Gauteng Province, South Africa. It is one of the country's three capital cities, serving as the executive and de facto national capital; the others are Cape Town, the legislative capital, and Bloemfontein, the judicial capital.Pretoria is...

 in 1935. In 1950 the sole Class 20 was modified to an experimental condensing locomotive, equipped with a condensing tender that was ordered from Henschel in 1948. Beginning in 1951, tests with the condensing Class 20 were conducted in the Eastern Transvaal and the Karoo

Karoo

The Karoo is a semi-desert region of South Africa. It has two main sub-regions - the Great Karoo in the north and the Little Karoo in the south. The 'High' Karoo is one of the distinct physiographic provinces of the larger South African Platform division.-Great Karoo:The Great Karoo has an area of...

. The positive results of the condensing trials proved the viability of condensing locomotives in South Africa

South Africa

The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...

 and led to the introduction of the Class 25 4-8-4

South African Class 25 4-8-4

Between 1953 and 1955 the South African Railways placed ninety Class 25 condensing steam locomotives with a 4-8-4 Northern wheel arrangement in service...

 condensing locomotive fleet in 1953.

Soviet Union

In the Soviet Union 2-10-2 type locomotives were used to haul heavy freight trains. Two series were relatively common, the FD (for Felix Dzerzhinsky)

Steam locomotive FD

The russian locomotive class FD FD from Felix Dzerzhinsky, russian: ФД from Феликс Дзержинский was a soviet russian main freight steam locomotive type. Between 1932 to 1942 years 3213 locomotives were built.- History :...

 with more than 3000 built through the 1930s, and the LV (Lebedyanskii, modified by the Voroshilovgrad factory).

The FD class was developed from ALCO and Baldwin heavy freight locomotives imported to Soviet Russia, where they were designated as Ta and Tb class respectively. In 1958, 1,054 FDs were sold to China, where they worked until the 1980s. A much lesser number were sold to North Korea around the same time.

The LV class was developed from the previous L-class 2-10-0 locomotive by the Voroshilovgrad factory. It used a feedwater heater

Feedwater heater

A feedwater heater is a power plant component used to pre-heat water delivered to a steam generating boiler. Preheating the feedwater reduces the irreversibilities involved in steam generation and therefore improves the thermodynamic efficiency of the system...

 to increase thermal efficiency and it was the most efficient freight steam locomotive in the Soviet Union with thermal efficiency of 9.3%. The first prototype was named OR18-01 (October Revolution factory, 18 tonne axle load). 522 LV-class locomotives were built. Several were preserved, including the first OR18-01 and the last LV-0522.

China

2-10-2s were the mainstay of Chinese steam, this being the arrangement of the Chinese QJ class locomotives, based in turn on the Soviet LV class, which were built until 1988 and were still in widespread service until the final steam runs in 2003.

Some of these QJs are finding their way to the United States for excursion service. In 2006, Multipower International, Inc. restored two Chinese QJ

China Railways QJ

The QJ was a type of heavy freight steam locomotive used by China Railways. The majority were made by Datong locomotive factory...

2-10-2 steam locomotives to FRA Part 230 specifications and delivered them to Railroad Development Corp.