London Underground infrastructure Tube Programme, investigating replacing the trains for the Bakerloo and Piccadilly lines, is looking for trains with better energy conservation and regenerative braking. The Underground serves 270 stations. Fourteen Underground stations are outside Greater London, of which five (Amersham, Chalfont & Latimer, Chesham, and Chorleywood on the Metropolitan line and Epping on the Central line) are beyond the M25 London orbital motorway. The longest distance between two stations is between Chalfont & Latimer and Chesham on the Metropolitan line. The shortest distance between adjacent stations is the between Leicester Square and Covent Garden on the Piccadilly line. The station furthest
History of the London Underground Farringdon to King's Cross in 1852 . Although the plan was supported by the City of London, the railway companies were not interested and the company struggled to proceed. In 1854 the Metropolitan Railway (also known as the Met) was granted permission to build an underground line at an estimated cost of £1 million. With the Crimean War under way, the Met found it hard to raise the capital, and construction did not start until March 1860. The railway was mostly built using the "cut-and-cover" method from Paddington to King's Cross; east of King's Cross it was built by tunnelling