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
Automation of the London Underground to open and close doors, and to assist in case of emergency. This method of working will be extended to the other lines by 2022 and will also be used on Thameslink and Crossrail. There are already driverless trains in operation on London second rapid transit system, the Docklands Light Railway (DLR), although this is a relatively newly built system. Boris Johnson promised in 2012 that there would be driverless Tube trains within 10 years. During his campaign to be re-elected as London Mayor, he said "TfL (Transport for London) will rapidly establish a timetable for introducing the first driverless