Britain's Railways are grouped into the <a href="https://en.wikipedia.org/wiki/List_of_railway_companies_involved_in_the_1923_grouping#The_Big_Four" id="mwAbw" rel="mw:WikiLink" title="List of railway companies involved in the 1923 grouping">Big Four</a>: <a href="https://en.wikipedia.org/wiki/London_and_North_Eastern_Railway" id="mwAb0" rel="mw:WikiLink" title="London and North Eastern Railway">LNER</a>, <a href="https://en.wikipedia.org/wiki/Great_Western_Railway" id="mwAb4" rel="mw:WikiLink" title="Great Western Railway">GWR</a>, <a href="https://en.wikipedia.org/wiki/Southern_Railway_(UK)" id="mwAb8" rel="mw:WikiLink" title="Southern Railway (UK)">SR</a>, and <a href="https://en.wikipedia.org/wiki/London,_Midland_and_Scottish_Railway" id="mwAcA" rel="mw:WikiLink" title="London, Midland and Scottish Railway">LMS</a>.<sup about="#mwt275" class="mw-ref reference" data-mw='{"name":"ref","attrs":{},"body":{"id":"mw-reference-text-cite_note-53"}}' id="cite_ref-53" rel="dc:references" typeof="mw:Extension/ref"><a href="./January_1#cite_note-53" id="mwAcE" style="counter-reset: mw-Ref 53;"><span class="mw-reflink-text" id="mwAcI">[53]</span></a></sup>
<span class="mw-reference-text reference-text" id="mw-reference-text-cite_note-53"><cite about="#mwt272" class="citation web cs1" id="mwDqE"><a class="external text" href="http://www.legislation.gov.uk/ukpga/Geo5/11-12/55/enacted" id="mwDqI" rel="mw:ExtLink nofollow">"Railways Act 1921"</a>. HMSO. 19 August 1921. <a class="external text" href="https://web.archive.org/web/20201112024029/http://www.legislation.gov.uk/ukpga/Geo5/11-12/55/enacted" id="mwDqM" rel="mw:ExtLink nofollow">Archived</a> from the original on 12 November 2020<span class="reference-accessdate" id="mwDqQ">. Retrieved <span class="nowrap" id="mwDqU">25 August</span> 2021</span>.</cite><span about="#mwt272" class="Z3988" id="mwDqY" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&amp;rft.genre=unknown&amp;rft.btitle=Railways+Act+1921&amp;rft.pub=HMSO&amp;rft.date=1921-08-19&amp;rft_id=http%3A%2F%2Fwww.legislation.gov.uk%2Fukpga%2FGeo5%2F11-12%2F55%2Fenacted&amp;rfr_id=info%3Asid%2Fen.wikipedia.org%3AJanuary+1"></span></span>