The London, Brighton and South Coast Railway E5 Class was a class of 0-6-2T side tank steam locomotive designed by Robert Billinton. They were introduced in 1902 and were a larger version of the E4 Class intended for semi-fast secondary passenger work.
As the weight of passenger trains continued to grow steadily during the 1890s and 1900s Robert Billinton decided to enlarge his radial tank classes still further by introducing a 5-foot-6-inch (1.676 m) wheeled version incorporating the C2 class boiler. Thirty E5 locomotives were built by Brighton Works between November 1902 and November 1904. In addition to more power and a higher top speed, they also had more fuel capacity than the E4 class.
The E5s were deemed to be fairly successful and locomotives achieved high mileages, but in 1911 four examples were rebuilt by D. E. Marsh with the larger C3 class boiler and were re-classified E5X. This experiment was not however a success and the performance was not greatly improved and higher centre of gravity made for rougher running at speed.
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 apex, practically the whole coastline of Sussex as its base, and a large part of Surrey. It was bounded on its western side by the London and South Western Railway (L&SWR), which provided an alternative route to Portsmouth. On its eastern side the LB&SCR was bounded by the South Eastern Railway (SER) – later one component of the South Eastern and Chatham Railway (SE&CR) – which provided an alternative route to Bexhill, St Leonards-on-Sea, and Hastings. The LB&SCR had the most direct routes from London to the south coast seaside resorts of Brighton, Eastbourne, Worthing, Littlehampton and Bognor Regis, and to the ports of Newhaven and Shoreham-by-Sea. It served the inland towns/cities of Chichester, Horsham, East Grinstead and Lewes, and jointly served Croydon, Tunbridge Wells, Dorking and Guildford. At the London end was a complicated suburban and outer-suburban network of lines emanating from London Bridge and Victoria, and shared interests in two cross-London lines.