 These were replaced in 1907 by the current electrically powered machines from Fullerton, Hodgart and Barclay of Paisley (the currently installed electric motors were manufactured by JH Holmes & Co, Hebburn-upon-Tyne and date from 1938-9).It powered the docks hydraulic system of cranes, bridges and locks.The tower houses a raised weight hydraulic accumulator which stores the hydraulic energy ensuring a smooth delivery of pressure and meaning that the pumps do not need to be running the whole time in order to satisfy peak demand.The external accumulator was added in 1954.