and those built after 1879 as B Class. When five Burnett 0-6-0 tank locomotives were received in 1868 for the St John's Wood Railway, they took the numbers 34-38, so the A Class consisted of Nos. 1-33 and 39-44. After the 0-6-0Ts were sold, the B Class reused the earlier numbers, becoming Nos. 34-38 and 50-66. Running Between 1880 and 1885, seventeen locomotives were reboilered at Edgware Road, and after 1886 this was done at Neasden Depot. At Neasden boiler pressure was increased to , and after 1894 the wheel diameter was increased to and the cylinders increased to . Cabs were fitted after 1895, although these became too hot when working in tunnels and were not popular with crews. Broken coupling rods were a cause of accidents in 1873 and 1884, and in 1885 the cross section was increased. The problem was eventually solved in 1893 when the original Allan motion was replaced by a Gibson & Lilley link motion, this being fitted to all locomotives by 1896. In 1898, No. 62 was experimentally fitted to burn oil, but oil of the right quality for underground use was too expensive. In 1921, further experiments were carried out with oil burning. The Metropolitan Railway A and B Class locomotives worked the whole of the Metropolitan Railway. In 1884, most of the locomotives up to No. 20 were stabled at Neasden, Nos. 27 to 33 were used on the East London Railway, the others from 21 to 50 were at Edgware Road and 51 to 66 at Hammersmith for the Hammersmith & City line. Withdrawal After electrification of the inner London lines in 1905-06, most of the locomotives were redundant. By 1907, forty had been sold or scrapped, No. 1 having been withdrawn earlier in 1897 after it was involved in an accident at Baker Street. Many locomotives went to R. Fraser and Sons for scrap by 1914, thirteen locomotives having been retained for shunting, departmental work and working trains over the Brill Tramway. The purchase of other locomotives, the closure of the Brill Tramway in 1935, and the transfer of freight duties to the LNER saw all but one of these remaining locomotives sold or scrapped around 1936. Class A No. 23 (LT No. L45) survived as a shunter at Neasden until 1948, and is now preserved at the London Transport Museum. No. 22 was sold to the District Railway