This is a list of Yorkshire Railways. Most were absorbed by larger railway companies which ended with two of the constituents of The Big Four (London Midland Scottish & London and North Eastern Railway) operating in the Yorkshire & Humber area. These companies were created under the Railways Act 1921 and the act came into effect on 1 January 1923. The Big Four existed for 25 years before being nationalized on 1 January 1948 under the Transport Act 1947. Privatisation in 1994 onwards has seen the railway ownership pass from British Rail to Railtrack and then onto Network Rail.