Why were the railways grouped?

By the early 20th century, the railways had grown to such an extent that competition was fierce and the market was fast becoming saturated, as a result, the railways were not run particularly well or efficiently.

Just how wasteful the network had become became apparent during the First World War when the railways were brought under state control. Bringing the railways under the control of a governing body had highlighted benefits in efficiency and led to this being a key strategy in the 'Railway Act 1921' which was designed to stem the loses of over 100 railway companies in the UK.

Initially, it was felt that complete nationalisation was the way to go, however, one of the Act's architects (Eric Geddes) wasn't convinced and campaigned for regional monopolies with localised knowledge and industry expertise to lead the way.

The result of this was nearly all of Britain's 120 railway companies being amalgamated into four privately owned railway companies comprising LMS (London, Midland and Scottish Railway), GWR (Great Western Railway), SR (Southern Railway) and the LNER (London and North Eastern Railway). These companies would later become collectively known as the Big Four.

The Big Four ruled the rails for over 20 years from commencement in 1923 until the 'Transport Act 1947' when Nationalisation resulted in the birth of British Railways.