History of the London Underground 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
London Underground 1972 Stock London Underground 1972 Stock The London Underground 1972 Stock is a type of rolling stock used on the London Underground. The 1972 Stock was ordered to make up the shortfall in trains on the Northern line's 1959 Tube Stock fleet. It is, however, currently used on the Bakerloo line. Following the withdrawal of the A Stock on the Metropolitan line in 2012, and the C Stock on the Circle, District and Hammersmith & City lines in June 2014, these trains are now the oldest trains on the London Underground and also on any rapid transit system in the United Kingdom.