Specification includes:

• NEM coupler pockets
• Highly detailed body and underframes
• Metal bearings
• Choice of two buffer types (five-plank only)
• Optional sheet rail (seven-plank only)
• Designed in the UK

Given the diagram '1355' by the Southern Railway, this seven-plank open was the SECR’s most numerous wagon. Over 2,000 were built between 1915 and 1927. The only design change that the Southern Railway made was to add a sheet rail.

The five-plank wagons used the same underframe but were technically classified as ‘rebuilds’ (only wheels and buffers were re-used). Some 550 (Southern Railway Dia. 1347s) were built, along with 150 near-identical (SR) Dia. 1349s.

Both designs lasted into BR days. Whereas the five-planks had gone by the mid-1960s, the last seven-planks were not withdrawn until the 1970s.