Big Four (British railway companies)

The Big Four was a name used to describe the four largest railway companies in the United Kingdom in the period 1923–47. The name was coined by The Railway Magazine in its issue of February 1923: "The Big Four of the New Railway Era".

The Big Four were:

• Great Western Railway (GWR)
• London, Midland and Scottish Railway (LMS)
• London and North Eastern Railway (LNER)
• Southern Railway (SR)

The companies were formed as a result of the Railways Act 1921, in a process known as "The Grouping" (of the railways), which came into effect on 1 January 1923.

On 1 January 1948, the companies were nationalised to form British Railways as a result of the Transport Act 1947.

• List of railway companies involved in the 1923 Grouping