The Southern inherited many wooden-bodied carriage designs from its constituent companies. However, there was an emphasis on standardising the coaching stock, which led to Maunsell designing new carriages. These were classified between 0 and 4, so that an 8' 0¾" wide carriage was "Restriction 0". The restrictions related to the Southern's composite loading gauge, so that some more restricted routes could be catered for. The new carriages were based upon the former LSWR "Ironclad" carriage designs, and comprised First and Third Class compartments, each of which contained a corridor and doors for each compartment, enabling quick egress on commuter services. Similar principles were applied to the electric train sets, where quick passenger egress promoted a punctual service.