when it was being extended to Queen's Park. Car 202 had its 'Nife' battery updated to one with 263 cells made by Edison Accumulator Ltd in 1924, while the number of cells in car 201 was increased from 200 to 238 in 1932. For working on other lines, they were fitted with outside shoes, since most lines used a four-rail system, whereas the CLR used only three. The vehicles were numbered L22 and L23 in 1929, and were scrapped in 1936 and 1937. When the City and South London Railway was being reconstructed in 1922, a number of "padded cell" trailer cars – so-called because of their lack of windows – were stripped out, so that lead-acid batteries and charging resistances could be placed in the resulting space. Each car was then coupled to an electric locomotive, and the batteries were connected to the shoe fuses of the locomotive. The current rail shoes were removed, so that the batteries did not energise the rails. Recharging was arranged at certain points, by means of switches and cables connected to the supply that normally fed the rails. Two Hungarian gate stock cars, which had previously been used as ballast motor cars, were converted to battery operation. When working as passenger vehicles on the Piccadilly line, they had been numbered 34 and 39. In 1929 they were transferred to the Hampstead line, where they were numbered 113 and 118, becoming L11 and L12 in 1936. Shortly afterwards, the numbers were swapped, so that L11 became L12 and L12 became L11. They used batteries made by DP Battery Company, each with 220 cells. The final conversion was of Bakerloo car 66, originally made by the American Car and Foundry Company, and fitted with a 220-cell DP battery weighing 6.5 tons in 1932. It was numbered L32, and was scrapped in 1948. Main battery locomotives In 1936, the decision was taken to purchase a batch of new battery locomotives, and an order was placed with the Gloucester Railway Carriage & Wagon Company for nine vehicles, six of which would be fitted with GEC traction control equipment, while the other three would be fitted with metadyne units. The GEC-fitted machines weighed 53.8 tons, and were numbered L35 to L40, while the Metadyne-equipped ones weighed an extra 2.2 tons, and were numbered L41 to L43. Both types, when pulling a 200-ton ballast train, could run at when