 The Transport Act 1947 nationalised nearly all forms of mass transport in Great Britain and came into effect on 1 January 1948.British Railways came into existence as the business name of the Railway Executive of the British Transport Commission (BTC) on 1 January 1948 when it took over the assets of the Big Four railway companies.A few independent light railways and industrial railways, which did not contribute significant mileage to the system, were not included in British Railways; nor the Glasgow Underground and London Underground, already both public concerns, the Liverpool Overhead Railway, and non-railway-owned tramways.