An 0-4-6, in 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 by 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...

, is a locomotive with 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 driving wheel

Driving wheel

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

s fixed in a rigid frame, and six 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 (normally mounted in a trailing truck). Examples of this type of locomotive were built by Wilhelm von Engerth

Engerth locomotive

The Engerth locomotive was a type of early articulated steam locomotive designed by Wilhelm Freiherr von Engerth for use on the Semmering Railway in Austria.- Designer :...

.

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...
  
  : B3 (also known as German classification and Italian classification)
• French classification: 023

History

This wheel arrangement was used on Engerth

Engerth locomotive

The Engerth locomotive was a type of early articulated steam locomotive designed by Wilhelm Freiherr von Engerth for use on the Semmering Railway in Austria.- Designer :...

 articulated

Articulated locomotive

Articulated locomotive usually means a steam locomotive with one or more engine units which can move independent of the main frame. This is done to allow a longer locomotive to negotiate tighter curves...

 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, widely used on Alpine railways. One early example was Genf built by Maschinenfabrik Esslingen

Maschinenfabrik Esslingen

Maschinenfabrik Esslingen , was a German engineering firm that manufactured locomotives, tramways, railway wagons, roll-blocks, technical equipment for the railways, , bridges, steel structures, pumps and boilers.-Founding:...

in 1858 for the Swiss Central Railway.