shuttle. In 1923 the London, Midland and Scottish Railway (LMS) had taken over the L&NWR railway's outer circle service from Earl's Court and by the Second World War this had been cut back to an electrified Earl's Court to Willesden Junction shuttle. Following bombing of the West London Line in 1940 the LMS and the Metropolitan line services to Addison Road were both suspended. After the war, to serve the Kensington exhibition halls a District line shuttle service started from Earl's Court to Addison Road, now renamed Kensington Olympia. The off-peak District Hounslow branch shuttle to South Acton was discontinued on 29 April 1935 and replaced by an Acton Town to South Acton shuttle. This shuttle was withdrawn on 28 February 1959, and the peak hour District line through service to Hounslow was withdrawn on 9 October 1964. In the 1970s the Hounslow branch became the Heathrow branch when it was extended to serve Heathrow Airport, first on 19 July 1975 to serve Hatton Cross and then on 16 December 1977 when Heathrow Central opened. Later on 27 March 2008, the branch was extended to Heathrow Terminal 5. Rolling stock Steam locomotives When in 1871 the District Railway needed its own locomotives, they ordered twenty four condensing steam locomotives from Beyer Peacock similar to the A Class locomotives the Metropolitan Railway was using on the route. As they were intended for an underground railway, the locomotives did not have cabs, but had a weatherboard with a bent-back top. The back plate of the bunker was raised to provide protection when running bunker first. A total of fifty four locomotives were purchased. They were still in service in 1905 when the line was electrified, and all but six were sold the following year. Electric locomotives In 1905 the District bought ten bogie box cab locomotives that looked similar to their multiple units but were only long. They were manufactured by the Metropolitan Amalgamated Carriage and Wagon Company and most had a single cab at one end. Consequently, they were operated in pairs, coupled back to back with the cabs at the outer end. The locomotives were used to haul L&NWR passenger trains on the electrified section of the Outer Circle route between Earl's Court and Mansion House. After December 1908 these services terminated at Earl's Court. The locomotives were used to haul District trains, one coupled to each end of a