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, 0-4-4 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 no 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, four 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 two axles, and four 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 two axles. This type was only used for 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.

In American cities, the type known as a Forney locomotive

Forney locomotive

The Forney is a type of tank locomotive patented by Matthias N. Forney between 1861 and 1864. Forney locomotives include the following characteristics:* An 0-4-4T wheel arrangement, that is four driving wheels followed by a truck with four wheels....

, was used on on the narrow curves of elevated railway

Elevated railway

An elevated railway is a form of rapid transit railway with the tracks built above street level on some form of viaduct or other steel or concrete structure. The railway concerned may be constructed according to the standard gauge, narrow gauge, light rail, monorail or suspension railway system...

s and other rapid transit

Rapid transit

A rapid transit, underground, subway, elevated railway, metro or metropolitan railway system is an electric passenger railway in an urban area with a high capacity and frequency, and grade separation from other traffic. Rapid transit systems are typically located either in underground tunnels or on...

 lines . In the UK 0-4-4 tanks were mainly used for suburban or rural passenger duties.

Equivalent classifications

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...
  
  : B2 (also known as German classification and Italian classification)
• French classification: 022
• 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...
  
  : 24
• Swiss classification: 2/4
• Russian classification: 0-2-2

USA

The 0-4-4 configuration was an enlargement of the 0-4-2

0-4-2

Under the Whyte notation for the classification of steam locomotives, 0-4-2 represents the wheel arrangement with no leading wheels, four powered and coupled driving wheels on two axles, and two trailing wheels on one axle...

 type and appears to have been introduced in the USA, with the Forney locomotive

Forney locomotive

The Forney is a type of tank locomotive patented by Matthias N. Forney between 1861 and 1864. Forney locomotives include the following characteristics:* An 0-4-4T wheel arrangement, that is four driving wheels followed by a truck with four wheels....

, was patented by Matthias N. Forney

Matthias N. Forney

Matthias Nace Forney was an American steam locomotive designer and builder. He is most well known for the design of the Forney type locomotive. Locomotives that he designed served the elevated railroads of New York City for many years before that system converted to electric power...

 between 1861 and 1864. These were characterized by a single frame under the boiler and fuel/water tank, which is supported at the rear by the truck under the coal bunker/water tank. The locomotives were designed to run cab (or bunker) first and were built for commuter lines in cities such as New York, Chicago and Boston.

UK

In the UK the earliest 0-4-4's were well tanks. Both John Chester Craven

John Chester Craven

John Chester Craven was the locomotive, carriage and wagon superintendent of the London, Brighton and South Coast Railway from 1847 until his resignation in 1870....

 of the London Brighton and South Coast Railway and James Cudworth

James Cudworth

James I'Anson Cudworth was Locomotive Superintendent of the South Eastern Railway . He served in this capacity from 1845–76...

 of the South Eastern Railway (UK)

South Eastern Railway (UK)

The South Eastern Railway was a railway company in south-eastern England from 1836 until 1922. The company was formed to construct a route from London to Dover. Branch lines were later opened to Tunbridge Wells, Hastings, Canterbury and other places in Kent...

 introduced classes in 1866. They were followed by Matthew Kirtley

Matthew Kirtley

Matthew Kirtley was an important early locomotive engineer. His brother Thomas Kirtley was also a locomotive engineer as was his nephew, William Kirtley, who served as locomotive superintendent on the London, Chatham and Dover Railway, 1874-1898.Kirtley was born in February 1813 at Tanfield,...

 on the Midland Railway

Midland Railway

The Midland Railway was a railway company in the United Kingdom from 1844 to 1922, when it became part of the London, Midland and Scottish Railway....

(26 locomotive built 1869-70) and Patrick Stirling

Patrick Stirling

Patrick Stirling was Locomotive Superintendent of the Great Northern Railway.His father Robert Stirling was also an engineer. His brother James Stirling was also a locomotive engineer...

 on the Great Northern Railway (48 locomotive built 1873-81). The more common side-tank version was introduced on the Great Eastern Railway

Great Eastern Railway

The Great Eastern Railway was a pre-grouping British railway company, whose main line linked London Liverpool Street to Norwich and which had other lines through East Anglia...

 by Samuel W. Johnson

Samuel W. Johnson

Samuel Waite Johnson was Chief Mechanical Engineer of the Midland Railway from 1873 to 1903. He was born in Bramley, Yorkshire and educated at Leeds Grammar School.-Career:...

 in 1872, and was soon afterwards adopted by most mainline railways in the UK, and became the standard configuration for a passenger tank locomotive until about 1900. Examples have included the LSWR O2 Class

LSWR O2 Class

The LSWR O2 Class is a class of 0-4-4T steam locomotive designed for the London and South Western Railway by William Adams. Sixty were constructed during the late nineteenth century.-Background:...

, Midland Railway 2228 Class

Midland Railway 2228 Class

The Midland Railway 2228 Class was a class of 0-4-4T side tank steam locomotive designed by Samuel Johnson. They were given the power classification 1P....

, the LSWR M7 Class

LSWR M7 Class

The LSWR M7 class is a class of 0-4-4 passenger tank locomotive built between 1897 and 1911. The class was designed by Dugald Drummond for use on the intensive London network of the London and South Western Railway , and performed well in such tasks. Because of their utility, 105 were built and the...

 and the Caledonian Railway 439 Class

Caledonian Railway 439 Class

The Caledonian Railway 439 Class is a class of 0-4-4T steam locomotive. It was a development of the earlier 19 Class and 92 Class 0-4-4Ts and predecessor of the 431 Class. The 439 Class was introduced by John F...

. The last British design of 0-4-4T were the LMS Stanier 0-4-4T

LMS Stanier 0-4-4T

The London, Midland and Scottish Railway Stanier 0-4-4T was a class of 10 light passenger locomotives built in 1932. Ostensibly designed under new CME William Stanier, they were in fact the last new design of the Midland Railway's school of engineering....

 of 1932 which were based on the Midland Railway 2228 Class

Midland Railway 2228 Class

The Midland Railway 2228 Class was a class of 0-4-4T side tank steam locomotive designed by Samuel Johnson. They were given the power classification 1P....

.