This book is a comprehensive history of all twenty-six classes of four coupled tank engines commissioned by the Great Western Railway or built at their Wolverhampton and Swindon Works, from the Broad Gauge 2–4–0 and 4–4–0 tanks of the 1840s and 1850s to the well known Collett 0–4–2 branch line engines of classes 48XX (later renumbered 14XX) and 58XX of the 1930s. As well as the Broad Gauge engines, the strange looking ‘Covertibles’ of William Dean, a number of experimental ‘one-off’ designs, the numerous Wolverhampton 0–4–2Ts of the ‘517’ class and the Swindon built ‘2–4–0 ‘Metro Tanks’ are described with — where known — their allocation and operation. The book includes twenty weight diagrams and nearly 300 photographs, over 50 in color. The four-coupled tank engines absorbed by the Great Western from other companies at or before 1923 will be featured in a separate volume to follow.
