Kempton Park Steam Engines

The Kempton Park steam engines (also known as the Kempton Great Engines) are two large triple-expansion steam engines, dating from 1926–1929, at the Kempton Park Waterworks in south-west London. They were ordered by the Metropolitan Water Board and manufactured by Worthington-Simpson in Newark-On-Trent.
Each engine is of a similar size to that used in RMS "Titanic" and rated at about . Each could pump of water a day, to reservoirs at Cricklewood, Fortis Green and Finsbury Park for the supply of drinking water to the north, east & west of London. Raw water was supplied to the waterworks by the Staines and Queen Mary Reservoirs, which stored water collected from the River Thames. They were the last working survivors when they were finally retired from service in 1980.
The engines are of an inverted vertical triple-expansion type, tall from basement to the top of the valve casings and each weighing over 800 tons. The engines are thought to be the biggest ever built in the UK.
One of the engines, called The Sir William Prescott, has been restored to running order and is the largest fully operational triple-expansion steam engine in the world. It may be seen in steam on various weekends during the year. The engine house also houses two steam turbine water pumps. One of these steam turbines has now been motorised to demonstrate its inner workings.
The waterworks is adjacent to the A316 (just before it becomes the M3 motorway), between Sunbury-on-Thames and Hanworth. The same site also features a 2-foot gauge steam railway, the Kempton Steam Railway, the largest steam railway offering rides to the public on selected days, in London.
The steam engines now form a museum operated by Kempton Great Engines Trust, a registered charity.