Housed in an Art Deco building, the Kempton Steam Museum preserves two of the largest steam engines ever built. The triple-expansion engines are 19-m high and pumped drinking water into reservoirs for the supply of London from 1929 to 1980. Steam was provided by six boilers fuelled by moving-chain grates. The engines were named after Sir William Prescott, chairman of the Metropolitan Water Board, and his wife Lady Bessie Prescott. In 2002, a new boiler house was built to allow one engine to be operated on steam days. Also on display are steam turbines, a collection of metres and gauges, recreated mercury-arc rectifiers, photographs and drawings. The site is owned by the company Thames Water but the engines are maintained by a charitable trust established in 1995. The narrow-gauge railway that brought coal to the waterworks from barges on the River Thames is preserved by volunteers.