In 1959 Associated Electrical Industries (AEI) created a self-contained company named AEI Traction Division to control the railway activities of both Metropolitan Vickers Electrical Company Ltd and British Thomson-Houston (BTH). Included in this company were the interests of the Metropolitan-Vickers General Railway Signal Co., (later to become GEC General Railway Signal). The newly formed company established its headquarters, at Trafford Park, Manchester, and operated from three other sites, Attercliffe Common in Sheffield, Rugby Works, and Stockton Works supplying traction motors, machines, control gear and mechanical parts of locomotives. AEI Traction Limited’s product range encompassed electric and diesel-electric locomotives; electrical equipment for tramcars, trolley buses, trolley mining locomotives, traction motors and gears. In 1969 AEI Traction Division merged with English Electric Traction to form English Electric-AEI Traction Division.

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.

The British Thomson-Houston Co. Ltd., (BTH) was created as a subsidiary of the General Electric Company, USA in 1896 to exploit the sale of products in the United Kingdom. BTH was a reconstruction of an existing firm, Laing, Wharton and Down (1886). The BTH manufacturing works were based at Rugby, Warwickshire and the company’s products included induction motors, alternators, switchgear, turbo-generators and turbines, as well as a large number of rotary converters and motor converters, primarily for chemical plants. During the First World War, BTH’s most significant contribution was the development of marine apparatus for the naval service. The 1920s saw a period of vast expansion for the company with new extensions built at many of its factories such as Willesden, Birmingham, Chesterfield and Lutterworth. BTH amalgamated with Metropolitan-Vickers Electrical Company Ltd to form Associated Electrical Industries (AEI) in 1928 although both companies retained their separate identities and continued to compete for the same contracts. BTH developed manufactured electric torpedoes and electrical components for aircraft engines, munitions, etc., during the Second World War and in 1935 independently of each other, BTH and Metropolitan-Vickers were the first two companies in the world to construct jet engines.

The Transport Act 1947 nationalised virtually all British transport, including the railways, waterways, and road haulage. These were transferred to a newly-created operating body, the British Transport Commission (BTC). The British Transport Commission began operations on 1st January 1948, under Chairman Sir (later Lord) Cyril Hurcomb. At this time, the British Transport Commission acquired the “Big Four” grouped railways, with virtually all minor railways as well, together with the London Passenger Transport Board. This automatically transferred the assets of the rail companies to BTC, including ships, ports, hotels, and investments in bus, coach, and haulage companies. Two bus companies, Tilling and Scottish Motor Traction, were soon added, as well as long-distance road hauliers. The Transport Act charged the British Transport Commission with the task of charged with “integrating” various forms of transport into single public service. The British Transport Commission did not directly operate transport services. Operations were delegated to five separately appointed executives: Docks and Inland Waterways, Hotels, London Transport, Road Transport, and Railways. The Railways Executive operated under the name British Railways. In 1949, the Road Transport Executive was divided into two separate executives: Road Haulage and Road Passenger. The Commission exercised financial control over these Executives, and managed them through schemes of delegation. The Commission attempted to fulfil its statutory duty to “integrate” public transport by introducing Area Schemes. These were designed to establish regional monopolies for road passenger transport, ports, and harbours. “Integration” was also to be promoted through Charges Schemes, in which the true costs of different modes of transport were to be reflected in the charges. This was designed to attract traffic to the most economic and efficient mode of transport. The structure of Executives was dramatically altered by the Transport Act 1953, which abolished all Executives, with the exception of London Transport. Responsibility for the operation and maintenance of transport systems was delegated to the chief regional managers. The railways were reorganised into a system of area boards for each of its six regions. In September 1953, Sir Brian Robertson became Chairman. Disposal of the haulage fleet also began at this time, but a lack of buyers made this difficult. Rising costs, industrial action and competition from road traffic meant that the British Transport Commission was in financial trouble by 1955. It sought relief from this by publishing The Modernisation and Re-equipment of British Railways, a plan which proposed an investment in the railways of £1,240m over fifteen years. The main features of this plan were the replacement of steam with electric and diesel traction, the electrification of principle routes, and the introduction of new coaching stock. Despite the modernisation plan, the financial position of the British Transport Commission worsened. Two government reviews, in 1956 and 1959, concluded that the Commission was unwieldy and had an insufficiently commercial outlook. Sir Brian Robertson retired in May 1961, and was replaced by Dr Richard Beeching. The BTC was abolished by the Transport Act 1962. It was replaced with five new authorities that were answerable to the Minister of Transport: the British Railways Board, the British Transport Docks Board, the British Waterways Board, the London Transport Board, and the Transport Holding Company. Dr Beeching became chair of the British Railways Board.