The book 'Brunel and After - The Romance of the Great Western Railway' [481] by Archibald Williams in 1925 has the above illustration (also used in book 'Twixt Rail and Sea) of the 'New Standard 20-ton Mineral Wagon'. The text accompanying the photograph states : -

Introduction of High Capacity Wagons - In co-operation with traders, to secure more economical and efficient transport of coal, the Great Western Railway successfully initiated in August, 1924, the adoption of a 20-ton wagon as the new standard for the conveyance of shipment coal in South Wales. The new wagon, considerable numbers of which are now in use, is destined to take the place of the 10- and 12-ton wagon ; and apart from export coal there is an indication that the bigger wagon will be utilised for inland coal, roadstone, and other minerals. The benefits accruing to the trader are substantial (apart from reduced construction and maintenance costs, increased capacity of sidings, etc.), the G.W.R. allow a rebate of 5 per cent. off the conveyance rate and a further reduction of 1¼d. per ton in tipping and weighing charges on coal conveyed in fully laden 20-ton wagons over their line. [481]