The SR electrified the London Victoria to Brighton line in the early 1930s, and full electric services commenced over the route from 1 January 1933. For the high-profile
Southern Belle Pullman train three five-car units, consisting entirely of Pullman cars, were built. All 15 cars were built by
Metropolitan Cammell. In June 1934 the Southern Railway renamed the
Southern Belle as the
Brighton Belle. As they were Pullman cars, owned by the independent
Pullman Car Company (UK), the individual carriages were numbered in its series, taking numbers 279 to 293, and the first class cars were given women's names while the third (from June 1956, second) class cars carried less-inspiring
Car No xx designations, derived from the second and third digits of the Pullman Car Company's number. However, the units together were allocated numbers in the SR series, originally taking , which was revised in January 1937 to . ==Formations==