The Metropolitan Railway (also known as the Met) was a passenger and goods railway that served London from 1863 to 1933, its main line heading north-west from the capital's financial heart in the City to what were to become the Middlesex suburbs. Its first line connected the main-line railway termini at Paddington, Euston, and King's Cross to the City.
The first section was built beneath the New Road using cut-and-cover between Paddington and King's Cross and in tunnel and cuttings beside Farringdon Road from King's Cross to near Smithfield, near the City. It opened to the public on 10 January 1863 with gas-lit wooden carriages hauled by steam locomotives, the world's first passenger-carrying designated underground railway.
The 3.75-mile (6 km) railway had stations at Paddington (Bishop's Road) (now Paddington), Edgware Road, Baker Street, Portland Road (now Great Portland Street), Gower Street (now Euston Square), King's Cross (now King's Cross St Pancras), and Farringdon Street (now Farringdon).
The railway was hailed a success, carrying 38,000 passengers on the opening day, using GNR trains to supplement the service. In the first 12 months 9.5 million passengers were carried and in the second 12 months this increased to 12 million. It was the origin of London Underground.
According to en.wikipedia