The Southern Railway took a key role in expanding the 660 V DC third rail electrified network begun by the London & South Western Railway. As a result of this, and its smaller operating area, its steam locomotive stock was the smallest of the 'Big Four' companies.
The SR N15X class or Remembrance class were a design of British 4-6-0 steam locomotives converted in 1934 by Richard Maunsell of the Southern Railway from the large LB&SCR L class 4-6-4 tank locomotives that had become redundant on the London–Brighton line following electrification. It was hoped that further service could be obtained from these locomotives on the Southern's Western Section, sharing the duties of the N15 class locomotives. The locomotives were named after famous Victorian engineers except for Remembrance, which was the LBSCR's memorial locomotive for staff members who died in the First World War.
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 (LSWR), and performed well in such tasks. Because of their utility, 105 were built and the class went through several modifications over five production batches. For this reason there were detail variations such as frame length. Many of the class were fitted with push-pull operation gear that enabled efficient use on branch line duties without the need to change to the other end of its train at the end of a journey.
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. They were also the last steam engines to work on the Isle of Wight, with the final two being withdrawn in 1967.
The London and South Western Railway B4 class is a class of 0-4-0 tank engines originally designed for station piloting and dock shunting. They were later used extensively in Southampton Docks for nearly half a century.
The LSWR S15 class is a British 2-cylinder 4-6-0 freight steam locomotive designed by Robert W. Urie, based on his H15 class and N15 class locomotives. The class had a complex build history, spanning several years of construction from 1920 to 1936. The first examples were constructed for the London and South Western Railway (LSWR), where they hauled freight trains to the south coast ports and further west to Exeter, as well as occasional passenger work in conjunction with their larger-wheeled N15 class counterparts.
The London and South Western Railway L11 class was a class of 4-4-0 steam locomotives designed for mixed traffic work. They were introduced in 1903 and were nicknamed "Large Hoppers". As with most other Drummond productions, the locomotive had two inside cylinders and Stephenson link valve gear.
The London and South Western Railway T9 class was a class of 66 4-4-0 steam locomotive designed for express passenger work by Dugald Drummond and introduced to services on the LSWR in 1899. One example has been preserved after British Railways ownership. They were given the nickname of "Greyhounds" due to their speed, up to 85 miles per hour (137 km/h), and reliability.
The London and South Western Railway T1 class was a class of fifty 0-4-4T steam tank locomotives designed for suburban passenger work by William Adams and built between 1888 and 1896.
The LSWR 415 class is a steam tank locomotive of 4-4-2T wheel arrangement, with the trailing wheels forming the basis of its "Radial Tank" moniker. It was designed by William Adams and introduced in 1882 for service on the London and South Western Railway (LSWR).
The LSWR 46 Class was a class of 4-4-0 passenger tank locomotive designed by William Adams for the London and South Western Railway. No examples have been preserved.
The LSWR G6 class was an 0-6-0T tank locomotive designed by William Adams for the London and South Western Railway.
The LSWR H16 class were five 4-6-2 tank locomotives designed by Robert Urie for the London and South Western Railway (LSWR) in 1921–1922. They were the last new design for the LSWR and their only Pacific-type design.
The LSWR T3 class was a class of express passenger 4-4-0 steam locomotives designed for the London and South Western Railway by William Adams. Twenty were constructed between 1892–1893.
The LSWR T6 class was a class of express passenger 4-4-0 steam locomotives designed for the London and South Western Railway by William Adams. Ten were constructed at Nine Elms Locomotive Works between 1885 and 1886.
The LSWR X6 class was a class of express passenger 4-4-0 steam locomotives designed for the London and South Western Railway by William Adams. Ten were constructed at Nine Elms Locomotive Works between 1885 and 1886.
The LSWR X2 class was a class of express passenger 4-4-0 steam locomotives designed for the London and South Western Railway by William Adams. Twenty were constructed at Nine Elms Locomotive Works between 1890 and 1892.
The LSWR 445 class was a class of express passenger 4-4-0 steam locomotives designed for the London and South Western Railway by William Adams. Twelve were constructed by Robert Stephenson and Company in 1883.
The LSWR 395 class was a class of goods 0-6-0 steam locomotives designed for the London and South Western Railway by William Adams as part of his modernisation programme. All 70 were constructed by Neilson and Company between 1881 and 1886. The last 34 locomotives differed in being slightly longer and heavier.
The LSWR 330 class or Saddlebacks was a class of goods 0-6-0ST steam locomotives designed for the London and South Western Railway. Twenty were constructed by Beyer, Peacock and Company between 1876 and 1882.
