Kempton Park Steam Engines

The Kempton Park steam 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 1,008 horsepower . Each could pump nineteen million imperial gallons 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, 62 feet 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.

Wikipedia