the Great Northern, Piccadilly and Brompton Railway, where they were numbered 1B and 2B. The vehicles were long, with a tube-gauge cab at both ends. Braking and electrical control equipment was housed in a compartment behind one of the cabs, and the central section was lower, housing the 80 batteries, arranged in two rows of 40 either side of a central divide, which also supported metal covers for the battery compartments. The batteries were supplied by Chloride Electrical Storage Company. Each locomotive weighed 55 tons, and could haul a 60-ton load at . They were not fitted with current collector shoes, as none of the rails were electrified during construction. Once their task was completed, they were moved by road to the Hampstead Railway. Encouraged by the performance of the vehicles, the District Railway purchased two of their own in 1909, which were larger as they were built to subsurface-gauge. The manufacturer was W. R. Renshaw and Co Ltd, who were based in Stoke-on-Trent in Staffordshire, and the vehicles were fitted with current collector shoes, so that they could draw power from the rails when it was available. During the First World War, they were used as shunting engines at Ealing Common Depot, where power was always available, and so the batteries were removed, and subsequently neglected. New batteries could not be obtained, as batteries of this type were needed for submarines as part of the war effort. The vehicles were numbered 19A and 20A when supplied, but were renumbered as L8 and L9 in 1929, when the batteries were no longer fitted. As electric locomotives, they were upgraded several times, receiving two new types of motors in 1951 and 1955, and new traction control equipment in 1958. They continued to be used to move stores between Acton Works and Ealing Common Depot, until they were superseded by road vehicles in 1969. Conversions The next batch of battery locomotives was made by converting existing stock. When it opened, the Central London Railway (CLR) had suffered from vibration problems, caused by the heavy locomotives, and had experimented with multiple unit operation, with motive power provided by converting four trailer cars to motor cars. Around 1910, two of these motor cars, numbered 201 and 202, were fitted with batteries, and worked on a number of lines in addition to the Central London Railway. In 1915 they were loaned to the Bakerloo line,