The railways of Britain were battered and bruised after the First World War. Over 20,000 miles of track were owned and operated by 120 companies, and the government decided the country could no longer support so many inefficient, diverse and, in some cases, overlapping operations.

To stem the mounting losses and regulate the system, the 1921 Railways Act, also known as the Grouping Act, became law on 1 January 1923. Just four large companies remained, nicknamed the 'Big Four': the LMS (London, Midland and Scottish Railway); the LNER (London and North Eastern Railway); the SR (Southern Railway); and the GWR (Great Western Railway).

Remembering the Big Four looks back at the Big Four railway companies, 100 years after they were drawn together. Complete with contemporary images of the locomotives inherited and built by each company, it is essential reading for any railway enthusiast.