When the Southern Railway was formed in 1923, it continued to build coach designs inherited from the main three constituent companies. Richard Maunsell introduced the SR’s first ‘standard’ coaches, building over 1,200 of them. These were formed into 139 sets, as it was the SR’s practice to keep coaches together for long periods of time, with a set number at each end. 
These coaches are the later 59ft type built from 1934 with flush sides, constructed with steel panels over a wooden framework. They were painted olive green in early SR days and, from 1939, in Bulleid’s malachite green, before most received the standard BR crimson and cream following nationalisation from 1949.