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
Too connected to fail the DebtRank for every node, which measures that in the case of the distress of the particular node what fraction of the total economic value is potentially affected. By doing this they identified the key financial institutions in the US between 2008 and 2010. Too connected to fail The "too connected to fail" (TCTF) concept refers to a financial institution which is so connected to other institutions that its failure would probably lead to a huge turnover in the whole system. Contrary to the "too big to fail" theory, this approach takes into consideration the highly connected network feature of