<P> From 1891, more locomotives were needed for work on the extension line from Baker Street into the country . Four C Class (0 - 4 - 4) locomotives, a development of South Eastern Railway's' Q' Class, were received in 1891 . In 1894, two D Class locomotives were bought to run between Aylesbury and Verney Junction . These were not fitted with the condensing equipment needed to work south of Finchley Road . Four more were delivered in 1895 with condensing equipment, although these were prohibited working south of Finchley Road . In 1896, two E Class (0 - 4 - 4) locomotives were built by the Met at Neasden works, followed by one in 1898 to replace the original Class A No. 1, damaged in an accident . Four more were built by Hawthorn Leslie & Co in 1900 and 1901 . To cope with the growing freight traffic on the extension line, the Met received four F Class (0 - 6 - 2) locomotives in 1901, similar to the E Class except for the wheel formula and without steam heat . In 1897 and 1899, the Met received two 0 - 6 - 0 saddle tank locomotives to a standard Peckett design . Unclassified by the Met, these were generally used for shunting at Neasden and Harrow . </P> <P> Many locomotives were made redundant by the electrification of the inner London lines in 1905--06 . By 1907, forty of the older class A and B had been sold or scrapped and by 1914 only thirteen locomotives of these classes had been retained for shunting, departmental work and working trains over the Brill Tramway . The need for more powerful locomotives for both passenger and freight services meant that, in 1915, four G Class (0 - 6 - 4) locomotives arrived from Yorkshire Engine Co . Eight 75 mph (121 km / h) capable H Class (4 - 4 - 4) locomotives were built in 1920 and 1921 and used mainly on express passenger services . To run longer, faster and less frequent freight services in 1925 six freight K Class (2 - 6 - 4) locomotives arrived, rebuilt from 2 - 6 - 0 locomotives manufactured at Woolwich Arsenal after World War I. These were not permitted south of Finchley Road . </P> <P> In 1933 the Metropolitan Railway was absorbed into the newly created London Passenger Transport Board and on 1 November 1937 the later G, H and K Class steam locomotives were transferred to the London and North Eastern Railway (LNER) who took over all freight workings and became responsible for hauling passenger trains with steam locomotives north of Rickmansworth . From the early 1940s these were replaced by ex Great Central Railway locomotives, now classified LNER Class A5 . These were replaced by LNER L1s after 1948 and ten years later in 1958 when the joint line was transferred to British Railway's London Midland Region former LMS locomotives replaced the L1s . Steam working ended on passenger trains after the introduction of the A Stock in 1961 . </P> <P> LT kept eleven locomotives for use departmental work . From 1956 these were replaced by ex-GWR 0 - 6 - 0PT pannier tanks, to be replaced by diesel - hydraulic locomotives in 1971 . </P>

When did the last steam train run on the london underground