Former Met tracks and stations are used by the London Underground's Metropolitan, Circle, District, Hammersmith & City, Piccadilly, Jubilee and Victoria lines, and by Chiltern Railways and Great Northern.

Costs were reduced by cutting back part of the route at the western end so that it did not connect directly to the GWR station, and by dropping the line south of Farringdon.

[18] Despite concerns about undermining and vibrations causing subsidence of nearby buildings[19] and compensating the thousands of people whose homes were destroyed during the digging of the tunnel,[20] construction began in March 1860.

[16] The line was mostly built using the "cut-and-cover" method from Paddington to King's Cross; east of there it continued in a 728 yards (666 m) tunnel under Mount Pleasant, Clerkenwell then followed the culverted River Fleet beside Farringdon Road in an open cutting to near the new meat market at Smithfield.

[31] After minor signalling changes were made, approval was granted and a few days of operating trials were carried out before the grand opening on 9 January 1863, which included a ceremonial run from Paddington and a large banquet for 600 shareholders and guests at Farringdon.

[32][37][l] The Metropolitan initially ordered 18 tank locomotives, of which a key feature was condensing equipment which prevented most of the steam from escaping while trains were in tunnels; they have been described as "beautiful little engines, painted green and distinguished particularly by their enormous external cylinders.

[43] With the problem continuing after the 1880s, conflict arose between the Met, who wished to make more openings in the tunnels, and the local authorities, who argued that these would frighten horses and reduce property values.

[33] The link to the West London Railway opened on 1 July that year, served by a carriage that was attached or detached at Notting Hill for Kensington (Addison Road).

A number of railway schemes were presented for the 1864 parliamentary session that met the recommendation in varying ways and a Joint Committee of the Parliament of the United Kingdom was set up to review the options.

[68] Starting as a branch from Praed Street junction, a short distance east of the Met's Paddington station, the western extension passed through fashionable districts in Bayswater, Notting Hill, and Kensington.

[74] East of Westminster, the next section of the District's line ran in the new Victoria Embankment built by the Metropolitan Board of Works along the north bank of the River Thames.

Struggling under the burden of its very high construction costs, the District was unable to continue with the remainder of the original scheme to reach Tower Hill and made a final extension of its line just one station east from Blackfriars to a previously unplanned City terminus at Mansion House.

[33] In 1868 and 1869, judgements had been against the Met in a number of hearings, finding financial irregularities such as the company paying a dividend it could not afford and expenses being paid out of the capital account.

[108][y] To serve the Royal Agricultural Society's 1879 show at Kilburn, a single line to West Hampstead opened on 30 June 1879 with a temporary platform at Finchley Road.

[123] The Met took over the A&BR on 1 July 1891[123] and a temporary platform at Aylesbury opened on 1 September 1892 with trains calling at Amersham, Great Missenden, Wendover and Stoke Mandeville.

[87] In 1895, the MS&LR put forward a bill to Parliament to build two tracks from Wembley Park to Canfield Place, near Finchley Road station, to allow its express trains to pass the Met's stopping service.

[137] Because of the state of the relationship between the two companies the MS&LR was unhappy being wholly reliant on the Met for access to London and, unlike its railway to the north, south of Aylesbury there were several speed restrictions and long climbs, up to 1 in 90 in places.

A train scheduled to use the GWR route was not allowed access to the Met lines at Quainton Road in the early hours of 30 July 1898 and returned north.

[151] The use of six-car trains was considered wasteful on the lightly used line to Uxbridge and in running an off-peak three-car shuttle to Harrow the Met aroused the displeasure of the Board of Trade for using a motor car to propel two trailers.

Eventually the UERL controlled all the underground railways except the Met and the Waterloo & City and introduced station name boards with a red disc and a blue bar.

[168] Suggestions of merger with the Underground Group were rejected by Selbie, a press release of November 1912 noting the Met's interests in areas outside London, its relationships with main-line railways and its freight business.

[178][ah] In 1912, Selbie, then General Manager, thought that some professionalism was needed and suggested a company be formed to take over from the Surplus Lands Committee to develop estates near the railway.

[181] Published annually until 1932, the last full year of independence, the guide extolled the benefits of "The good air of the Chilterns", using language such as "Each lover of Metroland may well have his own favourite wood beech and coppice — all tremulous green loveliness in Spring and russet and gold in October".

[190] The generating capacity of the power station at Neasden was increased to approximately 35 MW[191] and on 5 January 1925 electric services reached Rickmansworth, allowing the locomotive change over point to be moved.

[195] A possible route was surveyed in 1906 and a bill deposited in 1912 seeking authority for a joint Met & GCR line from Rickmansworth to Watford town centre that would cross Cassiobury Park on an embankment.

After the London Passenger Transport Bill, aimed primarily at co-ordinating the small independent bus services,[212] was published on 13 March 1931, the Met spent £11,000 opposing it.

[213] The bill survived a change in government in 1931 and the Met gave no response to a proposal made by the new administration that it could remain independent if it were to lose its running powers over the circle.

[209] On 1 July 1933, the London Passenger Transport Board (LPTB), was created as a public corporation and the Met was amalgamated with the other underground railways, tramway companies and bus operators.

The traffic reduced significantly when the GCR introduced road transport to Marylebone, but the problem remained until 1936, being one reason the LPTB gave for abolishing the carrying of parcels on Inner Circle trains.

[260] After some derailments in 1887, a new design of 27 feet 6 inches (8.38 m) long rigid-wheelbase four-wheelers known as Jubilee Stock was built by the Cravens Railway Carriage and Wagon Co. for the extension line.