former Metropolitan line stations between Amersham and . Victoria line and Jubilee line The Victoria line was recommended in a 1949 report as it would reduce congestion on other lines. After some experimental tunnelling in 1959, construction began in 1963 and, unlike the earlier tubes, the tunnels did not have to follow the roads above. The line was originally approved to run from Walthamstow to Victoria station, the extension to Brixton being authorised later. As part of the works, Oxford Circus station was rebuilt to allow interchange with the Central and Bakerloo lines. Cross platform interchanges were built at Euston, Highbury & Islington and Finsbury Park. After running trains from Walthamstow, first to Finsbury Park and then to Warren Street in 1968, the line to Victoria was officially opened in March 1969. The extension to Brixton opened in 1971. Designed for automatic train operation, access to the platforms was by using magnetically encoded tickets collected by automatic gates. The Moorgate tube crash occurred on 28 February 1975 on the isolated Northern City Line when a southbound train failed to stop at the Moorgate terminus and crashed into the wall at end of the tunnel, killing forty-four people. No fault was found with the train equipment, the subsequent report found that there was insufficient evidence to determine the cause. Following the incident, a system that stops a train automatically if the driver fails to brake was introduced at dead-ends on the London Underground. The Northern City Line was connected to British Rail tracks at Finsbury Park in the 1970s. The last tube train ran in October 1975, and British Rail services began in 1976. In 1977, the Piccadilly line was extended from Hounslow to Heathrow Airport, and in 1986 a platform serving Terminal 4 opened on a loop line. The Fleet line through central London was first proposed in 1965, taking over the Bakerloo line's Stanmore branch at Baker Street and then running via Fleet Street to Lewisham. To simplify planning the construction was divided into stages, and the first stage from Baker Street to Charing Cross had all the necessary approvals by 1971. Work began the following year and tunnelling had been completed in 1976. After the line had been renamed the Jubilee line in honour of Queen Elizabeth's Silver Jubilee in 1977, the line opened in April 1979 using trains that had been running on the Bakerloo line. 1980s