Railway had electrified in 1907, it sold most of its locomotives. In 1925 two locomotives (No. 33 and No 34) remained for departmental use. In 1926 No. 33 was scrapped and replaced by Metropolitan Railway A Class No. 22, which became District No. 35. These were replaced in 1931 by two 0-6-0T goods locomotives bought from the Hunslet Engine Company. When they passed to London Transport in 1933, they were numbered L.30 and L.31. They were withdrawn in 1963. In 1933 the Metropolitan Railway was still using steam locomotives on passenger trains. The LNER took over responsibility for steam working in 1937 and LT kept eleven locomotives for departmental work. From 1956 these were replaced by ex-GWR 0-6-0PT pannier tanks, to be replaced by diesel-hydraulic locomotives in 1971. In 1899 the Central London Railway had two tube-gauge steam locomotives that were oil fired underground and could run on coal above ground. They were sold by 1921. Battery-electric locomotives A fleet of 37 battery-electric locomotives are in service, able to take power from the electrified rails or from an on-board battery. Diesel locomotives A fleet of 4 diesel locomotives are currently used as shunting locomotives in Ruislip Depot due to growing restrictions on where they can operate on the network. Departmental stock Sleet locomotives Other stock See also Automation of the London Underground London Underground rolling stock numbering and classification Notes References Sources Snippet view at google.com, retrieved 20 August 2012 Further reading Lists of rolling stock