extensions had been suspended. The bombing of London and especially the Blitz led to the use of many tube stations as air-raid shelters, with 175,000 people arriving every night in August 1940. Six stations were breached by a direct hit, and in March 1943, 173 people died in a crowd crush accident at the unfinished Bethnal Green station. In the 1940s a depot built for the Northern line extension and an unfinished stretch of the Central line extension, the underground section between Newbury Park and Leytonstone, was turned into an aircraft factory. The closed Brompton Road station was used as an anti-aircraft control room. The closed Down Street station was used by Winston Churchill and the War Cabinet and the Railway Emergency Committee. Before the war, the Olympia exhibition centre had been served by the Metropolitan line and by a service from Earl's Court to . Following bombing in 1940 passenger services over the West London Line were suspended. This left the exhibition centre without a railway service, so after the war the station was renamed Kensington (Olympia) and served by a District line shuttle from Earl's Court. The Central line extensions in east and west London were completed, tube trains running to Epping from 1949. Nationalisation (1947–2000) Britain's railways were nationalised on 1 January 1948, and London Transport placed under the authority of the British Transport Commission (BTC). The BTC prioritised the reconstruction of the main line railways over the maintenance of the Underground and most of the unfinished plans of the 1935–40 New Works Programme were shelved or postponed. For the tube lines new cars (1949 Stock) were built to run with the 1938 stock. Some of the cars on the District line were in need of replacement, and in 1953 an unpainted aluminium train (R Stock) entered service, and this became the standard for new trains, and was followed by 1959 tube stock. After experiments with an AEC lightweight diesel multiple unit in 1952, steam trains were removed from the Central line following the electrification of the Epping–Ongar section in 1957. Between 1963 and 1970, London Transport reported directly to the Minister of Transport, before control passed to the Greater London Council. Electrification work on the Metropolitan line, suspended due to the war, had restarted in 1959. The line was electrified to and the unpainted aluminium (A Stock) replaced steam trains, British Rail providing services for the