The History of Kempton Park Pumping Station

Brief History

Kempton Park Pumping Station has been supplying fresh water to London since 1906. The site today is operated by Thames Water PLC and is also home to the Kempton Great Engines Trust.  Since 1995, the Trust has preserved the unique set of triple-expansion steam engines and turbines at Kempton Park, which served London for over fifty years.  

The New River Company established the Kempton Park works in 1897 to purify water abstracted from the River Thames at Staines and pump it to service reservoirs at Cricklewood.  Construction began in 1900 and was completed in 1906, by which time the New River Company and the seven other private water companies in London had been amalgamated into the Metropolitan Water Board (MWB).

The expansion of London necessitated the MWB to increase the capacity of the works in the 1920s with the installation of rapid primary filtration and additional steam pumping machinery. Primary filtration was cutting edge for its time, and the steam engines were amongst the largest of their kind in the world. Post-war, the site became a test bed for further filtration innovation, including the trialing of chemical treatments and rotary strainers. 

In 1973 the MWB’s governance was amalgamated with local wastewater facilities to form the Thames Water Authority. The clean water side of the operation then became known as the Metropolitan Water Division (MWD).

Steam power dominated Kempton Park until 1980, when the engines now preserved by Kempton Steam Museum were decommissioned in favour of more economical electric spindle pumps. 

Kempton Park still serves London through much of the original infrastructure laid down at the beginning of the last century. Since the 1990s, Kempton has also delivered water into the London Ring Main, which acts as an underground service reservoir circumnavigating London. The site, on average, supplies 130 Mega Litres (30 Million Gallons) of water to London daily.

In 1995 the Kempton Great Engines Trust was established with the aim to restore and showcase the surviving triple-expansion engines and steam turbines at Kempton Park Pumping Station. Since 2004, Kempton Steam Museum has welcomed thousands of visitors each year and endeavours to demonstrate the ‘Sir William Prescott’ engine in steam for many generations to come. 

The East London Water Works

Adjacent to Kempton Park site was the East London Water Works pumping station at Hanworth Road. The Works was commissioned in 1873 to pump water along a nineteen mile water main to a reservoir under Finsbury Park (Hornsey Wood Reservoir), for the supply of fresh water to the East End.  The works was designed by ELWW Chief Engineer Charles Greaves to overcome issues with the company’s intakes on the River Lea which tended to yield low volumes during the dry summer months and had been the root cause of a Cholera outbreak in 1866. 

Greaves constructed a river intake on the Thames at Sunbury where he installed two Bull steam engines. River water from Sunbury was pumped the short distance to Hanworth Road where it was stored in a raw water reservoir prior to filtration.  Alongside the reservoir were six slow sand filter beds, three Harveys of Hayle beam engines, ten Cornish boilers and a 250 foot high standpipe tower built to an Italianate style (Campanile). The beam engines had 84 inch diameter cylinders and an 11 foot stroke. Each engine in one stroke could pump 396 1/3 gallons of water. The pumping station had a normal daily output of 8 million gallons (increased to 12.6 million in 1911). 

After the creation of the Metropolitan Water Board and owing to their close proximity, the works at Kempton Park and Hanworth Road were combined, with interconnections made between the areas they both supplied. 

When the Staines Aqueduct was brought to Kempton Park, water was directed into the Hanworth Road Works, relinquishing the need for the Bull engines at Sunbury. The beam engines from 1906 found their load lightened when the new triple-expansion engines at Kempton were commissioned.  A spare engine at Kempton was given the duty to pump to Finsbury Park with the beam engines at Hanworth Road then only operating for a total of a month a year during times when all three Kempton engines were needed to pump to Cricklewood.

The beam engines were last recorded working during the hot summer of 1929 when two out of the three pumped constantly for a three month period. The engines were however always kept warm in readiness for being called into service. In 1933 two steam turbines were installed at Kempton Park finally making the beam engines redundant. The engines were formally decommissioned by the MWB Works & Stores Committee on the 22nd March 1934.  Owing to their engineering magnificence and representing the pinnacle of beam engine design,  the engines were then greased up and left with the intention to preserve them as museum pieces.

In 1939 the beam engines were recommissioned for stand-by purposes should any of the Kempton Park engines be damaged through enemy action. As the Cornish boilers had passed the end of their life, three Lancashire boilers were installed to supply steam.  The circumstances for the engines to be called into full action never fortunately arose as Kempton only received minor damage. The Hanworth Road works did however sustain a direct hit by a V2 rocket, destroying a filter bed and smashing the engine house windows.

Owing to post-war metal shortages, the beam engines were scrapped in 1947. The Hanworth Road filter beds remained visible until the 1990s when it was then used as a spoil dump for the London Ring Main project.

Click for further technical information about the Hanworth Road Beam Engines.

The New Pumping Station & Triple-Expansion Engines

London’s continual growth in the early part of the 20th century necessitated further expansion to the water supply infrastructure. In 1912 the MWB’s Chief Engineer Mr. W. B. Bryan recommended that Kempton Park should be expanded by constructing further slow sand filter beds and an additional pumping station which would also act as  an electric power station.  In the plan, three steam turbines would be installed each with the capability of pumping 15 million gallons per day along a 66 inch main to a new reservoir at Horsenden Hill in Hampstead.  In addition to the pumps were to be three steam turbine electric generators for powering electric water pumps intended for installation at Hanworth, Sunbury and Littleton.  Bryan also outlined plans for a new raw water storage reservoir at Littleton later known as the Queen Mary Reservoir to supply the new pumps at Kempton.

The MWB began approval of Bryan’s recommendations in 1914 but were shelved shortly after the outbreak of the First World War and the death of Bryan.  Sir James Restler succeeded as Chief Engineer and recommended the use of triple-expansion engines over steam turbines on the grounds of efficiency and reliability. Sir James Restler also died in office and was succeeded by Henry E. Stilgoe in 1920.

In 1920 Henry Stilgoe further advocated the expansion of Kempton Park works this time with rapid sand filters and triple-expansion engines. In 1924 the MWB accepted the tender of Worthington Simpson of Newark-on-Trent for two inverted marine type triple-expansion steam engines at a cost of £94,000. These engines would each have a maximum output of 19 million gallons of water per day and be amongst the largest steam engines ever built (now preserved by Kempton Steam Museum). Tenders were also received from William Moss & Sons for the construction of the Primary Filter and New Engine House at the combined cost of £245,000.  To power the engines, six Water Tube Boilers were ordered from  Babcock & Wilcox at a cost of £34,000. The boilers were fired with coal using an electrically driven moving chain grate.

Construction began in 1925 and was completed by 1929.  On the 24th October 1929 the pumping station was inaugurated by the Minister of Health, the Rt Hon. Arthur Greenwood M.P. in the presence of many dignitaries.  On the 8th November 1929 the two engines, Nos. 6 & 7  were named ‘The Sir William Prescott’ and ‘Lady Bessie Prescott’ engines respectively after the Chairman of the MWB and his wife.  

The installation meant an additional 24 million gallons of drinking water could be pumped to service reservoirs at Cricklewood, Highgate, Bishops Wood and Fortis Green. Water from these reservoirs would then flow by gravity for distribution to large parts of North, West and Central London.

Click for further technical information about the Triple-Expansion Engines. 

The Steam Turbines & The Dawn of Electricity

London’s continual expansion necessitated the output of the Kempton works to be increased. To meet this demand two steam turbines were installed in 1933. The two units were made by Fraser & Chalmers in Erith, Kent and numbered 8 and 9. They were installed in a space left between the two triple-expansion engines intended for a further engine or turbine equivalent.

The two turbines drove centrifugal water pumps made by Worthington Simpson and could deliver a total output of 24 million gallons of water each per day. Unlike the quiet and efficient running triples, the turbines were noisy and consumed considerably more steam. Their size and cost was however substantially less than a triple.

The turbines along with the triple-expansion engines were retired from service in 1980. The water pumping operations at the Kempton Park site are now undertaken by electric centrifugal pumps located in the old Lilleshall engine house.

Click for further technical information about the Steam Turbines.

Kempton Great Engines Trust & Kempton Steam Museum

After 1980, the steam engines and boilers at Kempton Park remained derelict with only the occasional film shoot or visit.  In 1993 the six Babcock & Wilcox and two John Thompson boilers were scrapped to make way for a Carbon Reactivation plant.  In 1995, Thames Water approached Nick Reynolds at Kew Bridge Steam Museum to establish a trust to preserve the steam engines.

In 1997 a 99 year lease was signed between Thames Water and The Kempton Great Engines Trust. The Kempton Great Engines Society was subsequently formed which recruited volunteers to undertake the restoration work. In 2002 the Sir William Prescott engine was returned to steam and the museum inaugurated by the HRH The Prince of Wales in December of that year.  Since 2004, Kempton Steam Museum has welcomed thousands of visitors and endeavours to maintain the collection for generations to come.

For further information about KGES or KGET, please see our About Us Page.

For further technical information please visit our Collection Page.