The city’s first underground line – and the first underground line in the world – was the Metropolitan Line, which opened in 1863 with the aim of helping to reduce London’s growing traffic congestion problem.
Running for three miles, the new railway, constructed by the Metropolitan Railway Company, ran for three miles under New Road, from Paddington to Farrington Street and took three years to build.
It was constructed using a technique known as “cut and cover” which involved digging a trench and building a tunnel inside before covering it back up.
Almost 40,000 passengers journeyed between Paddington and Farringdon on the day it opened, with the journey taking about 18 minutes.
The success of the new railway sparked a flurry of interest and in 1868, the first section of the District Line was opened, the same year the St John’s Wood Railway Company opened a line from Baker Street to Swiss Cottage.
Having grown substantially since it’s earliest days, today only six miles (9.7 kilometres) of the Metropolitan Line’s 41.5 miles (66.7) kilometres actually run underground.
The line now carries about 53 million passengers annually and 49 trains operate on it during peak periods.