Bentley Priory Museum 2026
Middlesex

Kempton's Triple is the world's biggest working example

Kempton't magnificent Art Deco engine house is now a National Monument
One of the UK's only working mercury arc rectifiers will fascinate kids with its eerie Dr Who lights
The 1008hp triples each pumped 19 million gallons a day until 1980
The 32-ton flywheels spin on the world's largest working Triple

Darent, Kempton's 1903 narrow-gauge locomotive is a family favourite
Home to the world's largest triple-expansion steam pumping engine. Housed in a magnificent 1927 Art Deco building preserved as a steam heritage site, the Great Triple can be seen in action on monthly steaming weekends.
Operator: The Kempton Great Engines Trust
Address: Kempton Park Waterworks Snakey Lane Hanworth Middlesex TW13 7ND
In Steam: 21-22 Mar; 18-19 Apr; 23-25 May; 20-21 Jun; 22-23 Aug; 19-20 Sep; 17-18 Oct; 21-22 Nov; 29-31 Dec. 1030-1600. Static: Sun 29 Mar-15 Nov. 1100-1500. (‘Sir William Prescott Engine’ will NOT be operating.) Visit website or facebook for more details and advance booking.
Kempton's magnificent 1927 engine house houses a pair of 1,000 ton triple-expansion steam pumping engines, one of which is now the largest working example in the world. It has been restored by volunteers over a 10 year period. Also on site are two steam turbines and a rare working mercury arc rectifier.
The building has been preserved as a heritage site, exactly as it was when it pumped millions of gallons of water a day to North London until it closed in 1980. The narrow-gauge railway operates every Sunday except December, plus steaming weekends.
Special events include car shows, model railway exhibitions and much more.
Guided tours always available plus a Guest Driver Experience for anyone wanting to have a go a running the Triple.