In 1900 the British Westinghouse Electrical & Manufacturing Co Ltd bought land in Trafford Park and built a factory which went into production in 1902 for the manufacture of mechanical and electrical equipment for the generation, transmission and use of electricity. In 1919, Trafford Park Works became owned by British Westinghouse’s successor, Metropolitan-Vickers Electrical Company (MV). The main shops, in common with factory construction throughout Trafford Park, were single floor type, with bays 1,000 feet in length, and had direct railway communication with the docks and trunk systems of the country. The main office block was a copy of the Westinghouse building in Pittsburgh, USA and the factory was to the American design and used imported steelwork for construction. Products manufactured at the Works included gas engines, stationary steam engines, electric generators, transformers, switchgear, meters, motors, control gear, and arc lamps. During the First World War, British Westinghouse built some small petrol-electric locomotives for the War Department Light Railways. In 1928 the Works were taken over by Associated Electrical Industries (AEI), which merged Metropolitan-Vickers and British Thomson-Houston, though these two companies continued their own trading names. Traction design and manufacture was always a minority of the workload at Trafford Park with the largest operations generally turbine manufacture. Very few vehicles were built there, and traction machines (i.e. motors, inductors and generators) were largely built in other places – notably at Sheffield or Rugby. Trafford Park traction manufacture was largely that of assembling control gear – contactors, switches, drivers’ controllers, camshaft controllers, relays etc. and building these into frames or equipment boxes for installation in vehicles made elsewhere. An important part of the Trafford Park Works site was the general switchgear operation, mainly for generation or distribution installations. The on-site Switchgear Testing Company was a “testing house” for these products and contributed to testing and development of traction circuit breakers and switchgear. During the Second World War MV acting for the Ministry of Aircraft Production produced more than a thousand Lancaster Bombers in the adjacent Mosley Road building. The company also manufactured war munitions and in the laboratories developed what became known as Radar. In 1959 the newly formed AEI Traction Division established its headquarters at Trafford Park, with a product range that included electric and diesel-electric locomotives; electrical equipment for tram-cars, trolley buses and trolley mining locomotives and traction motors. AEI was taken over by the General Electric Company (GEC) in 1967 whose Witton Works closed in 1969, with the design office and traction manufacture transferred to Trafford Park, as a result of the GEC reorganisation and mergers. GEC Traction Ltd took over the Works in 1972. In 1990 the former Low Voltage Switchgear site at Trafford Park (West Works) was renovated to be the new manufacturing facility for GEC Alsthom Traction, with an electronics workshop, machine shop and plating baths, and an assembly shop for switchgear, equipment cases and power modules. This building was vacated in 1998 when power modules and switchgear was moved to Tarbes in south west France. The Works housed the administrative, commercial and accounting functions, the majority of the design departments and the development section with its associated workshops and laboratories. The manufacturing area was devoted primarily to the production of components of traction control and railway signalling equipment. In 1993, as part of the rationalisation of the equipment group, it was announced that the headquarters of GEC Alsthom Traction would move to Preston, leaving only Power Module design and manufacture at Manchester, with the eventual closing of all activities at Trafford Park in 1998. The iconic original Westinghouse building was demolished and the site is now (2015) largely devoted to container handling and logistics operations.

In 1910 the state-owned South African Railways and Harbours (SAR&H) organisation was created, after the four colonies of the Cape, Natal, Transvaal and the Orange Free State were amalgamated into the new Union of South Africa. In 1916, SAR&H took over the activities of the Central South African Railways, the Cape Government Railways and the Natal Government Railways. In 1924 the last privately owned railway line in South Africa was taken over by SAR&H; the New Cape Central Railway between Worcester and Voor Bay. In 1920 electrification of South Africa’s railways was completed, and in 1924 the first electric test train ran between Ladysmith and Chieveley in Natal. In 1950 the first portion of the new Johannesburg station was opened and construction was completed on the huge workshops complex at Koedoespoort. In 1960, diesel locomotives were introduced on a large scale to SAR&H. In 1981, SAR&H changed its name to South African Transport Services (SATS) and took on South Africa’s railway, harbour, road transport, and aviation and pipeline operations.

The British Railways Board was an independent statutory corporation responsible for running the British railway network from 1963. It was established by the Transport Act 1962, which abolished the British Transport Commission and divided its undertakings between five newly-created bodies: the British Railways Board, the British Waterways Board, the British Transport Docks Board, the London Transport Board, and a Transport Holding Company. The British Railways Board was responsible for running the railway network, as well as managing government-owned railway hotels. Members of the British Railways Board were also appointed by the Minister for Transport. The first Chair of the British Railways Board was Dr Richard Beeching. The British Railways Board operated through regional boards, which were responsible for regional sections of the railway network. These regions were Southern, Western, London Midland, London and North Eastern, Eastern, and Scottish. Members of these regional boards were appointed by the British Railways Board, in consultation with the Minister for Transport. The British Railways Board also operated a series of committees to manage every aspect of railway control, including committees for finance, technical, works and property. These committees were frequently reorganised throughout the life of the British Railways Board, under both different Chairs of the Board and different governments. Several changes occurred during the 1960s. The Board had two new Chairs; Stanley Raymond, who replaced Richard Beeching in 1965, and his successor Henry Johnson, who became Chair in 1967. In 1968, the Transport Act transferred the control of the Sundries and Freightliner divisions from the British Railways Board to National Carriers Ltd and Freightliners Ltd. The Board retained a forty-nine per cent stake in Freightliners Ltd. During the 1970s, the British Railways Board created several subsidiary companies which were to manage some of its undertakings. These included British Transport Hotels Ltd, British Rail Engineering Ltd, and British Rail Hovercraft Ltd. Many of these subsidiary companies were sold under the Conservative governments of the 1980s. There were also two new Chairs during this time. Richard Marsh replaced Henry Johnson in 1971, and Peter Parker became chair in 1976. The privatisation of the British rail network during the 1990s radically changed the role of the British Railways Board. The Transport Act 1993 established Railtrack, a publicly-owned company. The Act transferred the ownership of track and railway infrastructure from the British Railways Board to Railtrack, in addition to the control of signals. Railtrack also replaced the British Railways Board as the body responsible for track investment and maintenance. The British Railways Board remained in existence after these changes, but only performed residual functions relating to pensions, liabilities, and non-operational railway land. The Board also continued to operate the British Transport Police service. The British Railways Board was abolished by the Transport Act 2000, which transferred the remaining functions of the Board to the newly-created Strategic Rail Authority.

GEC Traction (GECT) was formed in 1972 as part of the GEC Power Engineering Group following earlier amalgamations of the traction divisions of the General Electric Company (GEC), the English Electric Company (EE) and Associated Electrical Industries (AEI). A wholly owned subsidiary company of GEC, the company had offices and works, located at Trafford Park in Manchester, at Strand Road in Preston, and at Attercliffe Common, Sheffield. The headquarters of GEC Traction was Trafford Park, Manchester (previously the headquarters of English Electric-AEI Traction) with design of rotating machines at Preston and Sheffield, and manufacturing activities for control equipment at Manchester and Preston. GEC Traction designed and manufactured a full range of traction machines and control equipment for electric vehicles, including electric locomotives and multiple unit trains for main-line and mass-transit railway systems (dc up to 3,000 volts, and ac up to 50,000 volts), diesel-electric locomotives and trains, mining and industrial locomotives, tramcars and trolleybuses. GEC Traction was the leading supplier of traction equipment in the UK and had a wide market around the world, particularly in South Africa, Australasia, Hong Kong, South Korea, South America and Pakistan. In 1979 the Industrial Locomotive Division of the former English Electric which was based at Vulcan Works, Newton-le-Willows was merged into GEC Traction, which later became a separate company, GEC Industrial Locomotives Ltd. During the late 1980s and 1990s the firm underwent major rationalisation, involving closure of several sites including Attercliffe Common in Sheffield in 1985 and the company’s headquarters at Trafford Park in Manchester in 1998. The company name GEC Traction endured until a merger with the French Alsthom group in 1989, which created GEC Alsthom Traction, which was still a branch of the main company GEC Alsthom.

In 1947, a major portion of the North Western Railways 8,122 kilometer route (5,048 mi) was transferred to Pakistan and named the Pakistan Western Railway. The remaining 3,133 route kilometers (1,947 mi) were transferred to Indian control. In May 1974 it was renamed Pakistan Railways.