The Metropolitan Railway was the first underground railway to open in the world. The railway proved to be a success from the first day and was quickly extended.

Creating the Metropolitan railway

Construction of the Metropolitan Railway began in March 1860, despite concerns about undermining and vibrations causing subsidence to buildings and thousands of homes being destroyed. The railway was mostly constructed using the ‘cut-and-cover‘ method, which evolved digging a trench 10.2m (33ft 6in) wide and constructing a retaining wall supporting an elliptical brick arch or iron girders to form the roof of the tunnel, with a wider construction to accommodate stations.

The Metropolitan Railway opened to the public on Saturday, 10 January 1863 and ran 3.75 miles (6km) from Paddington to Farringdon Street. The railway proved a success from its first day, carrying 38,000 passengers on its first day, with 9.7 million passengers using the railway within the first 12 months of the railway opening.

Extending the Metropolitan railway

Farringdon to Moorgate

The Metropolitan Railway obtained permission in 1861 for two additional tracks to run between King‘'s Cross and Farringdon and for a four-track extension to Moorgate. This extention opened on 23 December 1865, with all four tracks being opened on 1 March 1866.

Creating the Hammersmith and City railway

The railway became increasingly popular and prompted a bill to be passed to Parliament in 1860, to allow for the running of Metropolitan railway services to Hammersmith via Shepard's Bush connecting at Latimer Road. This was approved on 22 July 1861, which opened on 13 June 1864.

The ‘Inner Circle‘

After the success of the Metropolitan Railway in 1863, Parliament received a flurry of railway proposals, to consider the best proposals a committee was set up to create a report, which was published in July 1863 and recommended the creation of a ‘inner circuit of railway that should abut, if not actually join, nearly all of the principal railway termini in the Metropolis‘.

The Metropolitan railway created proposals to extend from Paddington to South Kensington and Moorgate to Tower Hill, which where accepted and received Royal Assent on 29 July 1864.

To complete the circle, the committee encouraged the amalgamation of two schemes, and the Metropolitan District Railway (commonly known as the District Railway was agreed on 29 July 1864. The initial intention was that the two companies would merge, but a separate identity was established to allow the companies to raise their own money. However, the ‘Inner Circle‘ was operated as a single contract.

The extension from Paddington to Gloucester Road (opened as Brompton) opened on 1 October 1868, with a further extension to South Kensington allowing for a connection to the District Railway.

The ‘inner circle‘ opened in 1871, with services running from Mansion House and Moorgate via South Kensington and Paddington, with separate running tracks between the Metropolitan Railway and District Railway between High Street Kensington and South Kensington. The District Railway operated with Metropolitan Railway stock until 3 July 1981 when the railway began operating its own stock.

The Metropolitan railway still planned to extend further eastwards after obtaining an extension to their planned time limit in 1869, construction began in 1873. The extension to Liverpool Street opened on 12 July 1875 and the terminus at Aldgate was opened on 18 November 1876.

In 1882, the Metropolitan railway was further extended from Aldgate to a temporary station at the Tower of London. A full 'inner circle' service began on 6 October 1884, with the temporary station at Tower of London closing on 12 October 1884.

Baker Street to Harrow

The Metropolitan and St John's Wood Railway opened a short single-track railway from Baker Street to Swiss Cottage, in 1868. There was a extension to the railway in 1873 Neasden; with another extension to Harrow being approved in 1874. The extension opened in stages, the extension to Kilburn with a temporary station at Finchley Road opened on 30 June 1879, with service on the railway to Willesden Green commencing on 24 November 1879. The service to Harrow-on-the-Hill opened on 2 August 1880.

The Metropolitan and St John‘s Wood Railway was operated as a part of the Metropolitan Railway and was amalgamated in 1879.

Extending beyond Harrow

The Metropolitan Railway sought permission to extend the railway from Harrow to Aylesbury in 1881, the railway reached Pinner in 1885, with a service from Rickmansworth and Northwood to Baker Street beginning on 1 September 1887. Later in 1885, the Metropolitan Railway sought permission to extend further, with a 8km (5 mile) extension to Chesham, with services beginning on 8 July 1889 between Chorley Wood and Chlalfont and Latimer.

The Metropolitan Railway took over the Aylesbury and Buckingham Railway on 1 July 1891 and opened a temporary platform at Aylesbury in 1882 with services operating to Stoke Mandeville. A permanent station at Aylesbury was opened in 1894.

A branch was constructed from Harrow-on-the-Hill to Uxbridge in 1904.

21 Years elapsed until the railway was further extended, in 1925 the railway was extended from Moor Park via Croxley to Watford. In 1932 the line was further extended from Wembley Park to Stanmore, however this only operated as a part of the Metropolitan Railway for 7 years before being transferred to the Bakerloo Line, which also took over the Metropolitan Railway's stopping services.

The Metropolitan line today

The Metropolitan Railway began running electric services on 1 January 1905, with all services between Baker Street and Harrow being electric by 20 March 1905. The railway beyond Harrow was not electrified, and from 1 July 1907 an exchange to steam locomotives was made at Wembley Park. This was moved to Harrow on 19 July 1908 until the railway was electrified to Rickmansworth in 1925. The Watford branch, which began its operations in 1925, however steam was still in use of Rickmansworth until 1961 when the line was electrified to Amersham and Chesham further to this the service beyond Amersham was handed over to British Rail now Chiltern Railways.

Today, the Metropolitan line spans 66.7km (41.5 miles), with only 9.7km (6 miles) in tunnel. The line serves 34 stations, over the mainline from Aldgate to Amersham and branches to Chesham, Uxbridge and Watford. The busiest station on the line is Kings' Cross St Pancras, with 87 million passengers a year. The line also boasts the longest distance between stations on the London Underground network, between Chesham and Chalfont & Latimer with a distance of 6.26km (3.89 miles); further to the most westerly point on the London Underground network, 43km (27 miles) from central London and 147m (490ft) above mean sea level.