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 (752 kW).

[1] Each could pump nineteen million imperial gallons (86,000 m3) 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.

[2] The engines are of an inverted vertical triple-expansion type, 62 feet (19 m) tall from basement to the top of the valve casings and each weighing over 800 tons.

[4] It may be seen in steam on various weekends throughout the year, and as a static display every Sunday between March and November.