A radial axle is an axle on a railway locomotive or carriage which has been designed to move laterally, along the arc of a circle, when entering a curve in order to reduce the flange and rail wear. William Bridges Adams was an early developer of radial axles. Radial axles were widely used on carriages in the late 19th century before the adoption of

bogie A bogie ( ) (in some senses called a truck in North American English) is a chassis or framework that carries a wheelset, attached to a vehicle—a modular subassembly of wheels and axles. Bogies take various forms in various modes of transp ...

s. They were also used on the leading or trailing carrying axles of locomotives, particularly tank locomotives. The idea was tried successfully by William Adams on the

London and South Western Railway The London and South Western Railway (LSWR, sometimes written L&SWR) was a railway company in England from 1838 to 1922. Originating as the London and Southampton Railway, its network extended to Dorchester and Weymouth, to Salisbury, Exeter ...

in 1882 in a class now known as "Adams Radials". Radial axles were also used in locomotives designed by F.W. Webb of the

London and North Western Railway The London and North Western Railway (LNWR, L&NWR) was a British railway company between 1846 and 1922. In the late 19th century, the L&NWR was the largest joint stock company in the United Kingdom. In 1923, it became a constituent of the Lo ...

, and by

William Stroudley William Stroudley (6 March 1833 – 20 December 1889) was an English railway engineer, and was one of the most famous steam locomotive engineers of the nineteenth century, working principally for the London, Brighton and South Coast Railway (L ...

and

R. J. Billinton Robert John Billinton (5 April 1844 – 7 November 1904) was the Locomotive, Carriage, Wagon and Marine Superintendent of the London, Brighton and South Coast Railway from 1890 until his death. Early career He was born in Wakefield either on 5 Ap ...

of the

London Brighton and South Coast Railway The London, Brighton and South Coast Railway (LB&SCR; known also as the Brighton line, the Brighton Railway or the Brighton) was a railway company in the United Kingdom from 1846 to 1922. Its territory formed a rough triangle, with London at its ...

. Webb's form of radial axle used a

cannon box bearing A cannon bearing or cannon box bearing is an arrangement of bearings on a shaft, usually an axle, where two bearings are mounted in an enclosed tube. The function of the cannon box is to preserve the alignment of the two bearings, even if the over ...

where the two axle bearings are carried in a single curved casting, the 'cannon box', which can slide sideways in a circular track. David Joy, designer of the eponymous valvegear, described encountering these axleboxes on Webb's Precedent class. The earlier Adams design had relied on the axle and thrust-faces within the axle bearings to keep the hornblocks in position.

Sources

* {{Locomotive running gear Steam locomotive technologies Train axles