Anniversaries in September
- 1 September
- 1866 – Cannon Street station opens as the City of London terminus of the South Eastern Railway.
- 1887 – Metropolitan Railway extends from Pinner to Rickmansworth.
- 1892 – Metropolitan Railway extends from Chalfont & Latimer to Aylesbury.
- 1913 – Metropolitan Railway takes over the Great Northern and City Railway.
- 1939 – Great Western Railway ends passenger services on Denham to Uxbridge High Street branch line.
- 1968 – Victoria line opens between Walthamstow Central and Highbury & Islington.
- 2 September
- 1861 – Kentish Town rail accident kills 16 when a freight train and passenger train collide at a junction near Kentish Town station.
- 1958 – A crash of an Independent Air Travel cargo plane in Southall kills the 3 crew and 4 people on the ground.
- 3 September
- 1878 – A collision with the collier Bywell Castle kills over 650 passengers on the paddle steamer Princess Alice when it sinks near North Woolwich.
- 4 September
- 1934 – Two freight trains collide at Hither Green yard.
- 1938 – A crash of an RAF training aircraft into houses at Edmonton kills the pilot and 12 people on the ground.
- 5 September
- 2006 – London Overground brand introduced.
- 6 September
- 1975 – Northern line Highbury Branch closes between Moorgate and Old Street in preparation for transfer to British Rail operation.
- 7 September
- 1862 – Birth of Sir Edgar Speyer, Chairman of Underground Electric Railways Company of London and financier.
- 1940 – First use of tube stations as air raid shelters.
- 8 September
- 1973 – The IRA explode a bomb at Victoria station injuring 4.
- 1856 – Great Western Railway opens branch line from West Drayton to Uxbridge Vine Street.
- 9 September
- 1874 – District Railway extends from Earl's Court to Hammersmith.
- 10 September
- 1961 – Last steam- and electric-locomotive hauled services on the Metropolitan line.
- 1961 – Metropolitan line services end between Amersham and Aylesbury.
- 1962 – British Railways ends passenger services on West Drayton to Uxbridge Vine Street branch line.
- 1973 – The IRA explode bombs at King's Cross and Euston stations.
- 11 September
- 1805 – Failure of a mooring chain at Blackwall allows a number of merchant ships to drift in the Thames and Boddington, runs aground on a sandbank, sinks and is wrecked.
- 1939 – London North Eastern Railway branch line from Finchley Central to Edgware closes for conversion to London Underground operation.
- 12 September
- 1901 – District Railway sells Brompton and Piccadilly Circus Railway to the Metropolitan District Electric Traction Company.
- 1932 – District line extends from Barking to Upminster.
- 1960 – Rickmansworth to Amersham and Chalfont & Latimer to Chesham sections of Metropolitan line electrified.
- 13 September
- 1926 – City and South London Railway extends from Clapham Common to Morden.
- 1926 – Charing Cross, Euston and Hampstead Railway extends from Embankment to Kennington to connect to the City and South London Railway.
- 14 September
- 1862 – Death of Charles Pearson, promoter of an underground railway for London.
- 15 September
- 1881 – A collision between two trains near King's Cross station due to a signalling error kills one.
- 1936 – A British Airways Ltd De Havilland D.H.86 night mail plane crashes shortly after take-off from Gatwick Aerodrome, killing three crew and injuring one other.
- 1940 – Part of a Dornier Do.17 Z, crashes into the roof of Victoria station having been rammed by the Hawker Hurricane of Ray Holmes.
- 1952 – British Railways passenger services between Belmont and Stanmore end.
- 2017 – A bomb attack on a London Underground train at Parsons Green injures 30, mostly with burns.
- 16 September
- 1920 – Sopwith Aviation and Engineering Company closes at Kingston with the assets taken over by H G Hawker Engineering.
- 17 September
- 1770 – Limehouse Cut opens, London's first canal.
- 1999 – Jubilee line extends from North Greenwich to Bermondsey.
- 18 September
- 19 September
- 1932 – Piccadilly line extends from Finsbury Park to Arnos Grove.
- 1997 – Southall rail crash kills 7 when a train passes a signal at danger and collides with another.
- 20 September
- 1954 – British Railways closes branch from Nunhead to Crystal Palace (High Level).
- 2021 – Northern line opens branch from Kennington to Battersea Power Station.
- 21 September
- There are no anniversaries today
- 22 September
- There are no anniversaries today
- 23 September
- 1868 – Aylesbury and Buckingham Railway opens between Aylesbury and Verney Junction.
- 1968 – The driver of a ballast train dies when it crashes into the rear of a Bakerloo line train at Neasden having passed three signals at danger.
- 24 September
- 1982 – Bakerloo line services end between Harrow & Wealdstone and Watford Junction.
- 1999 – Jubilee line extends from Bermondsey to Waterloo.
- 25 September
- 1882 – Metropolitan Railway extends from Aldgate to Tower of London.
- 1940 – Second Wandsworth Bridge opens.
- 1940 – A German bomb kills 8 at Colindale station.
- 1949 – Central line extends from Loughton to Ongar.
- 26 September
- 1819 – Birth of Sir Edward Watkin, railway executive.
- 1873 – First Wandsworth Bridge over the River Thames opens.
- 1977 – Sir Freddie Laker's inaugural low-cost transatlantic Skytrain service flies from Gatwick Airport to John F. Kennedy International Airport.
- 27 September
- There are no anniversaries today
- 28 September
- 1973 – A bomb explodes at the West London Air Terminal in Cromwell Road injuring 8.
- 29 September
- 1799 – Birth of Lewis Cubitt architect of Bricklayers Arms and King's Cross stations.
- 30 September
- 1885 – District Railway ends services between Ealing Broadway and Windsor.
- 1905 – District Railway ends services between Barking and Upminster.
- 1939 – District line ends services between Upminster and Southend.
- 1959 – First section of Chiswick Flyover opens.
- 1994 – Piccadilly line ends services on the Aldwych branch.
- 1994 – Central line ends services between Epping and Ongar.
