Some might say that this is a freelance design. But we Archer’s* fans know better. This is a quarter inch scale model of the triple expansion engine at the Ambridge pumping station of the Borchester & District Water Board. It delivered one million gallons a day to the reservoir on Lakey Hill, presumably from the River Am.

The model was designed and constructed by Neil Carney of Bolton over a period of four years, and was a real head turner at the National Model Engineering and Modelling Exhibition at Harrogate in 2010.

It reminded us of the rather larger Kempton Great Engines west of London which supplied London with 19 million litres of water a day .

Standing nearly 62 ft high and weighing 800 tonnes, Engine No. 6 (also known as Sir William Prescott after the British engineer and politician) is the largest, triple expansion engine in the world and the only one in existence powered by steam.

Sir William is one of two great engines (six storeys high) of the Kempton Great Engines Trust, he sits next to his wife Bessie, Engine No.7.  (Billy and Bessie - another soap, perhaps?)The engine was built by Worthington Simpson Ltd, at their engine works at Newark on Trent and designed by the Metropolitan Water Board under the direction of engineer Henry Stilgoe. There are only a few comparable engines in working order but none in steam.

It was built in 1928 and was designed for 24-hour, 7 days-a-week operation, though in practice they were run overlapped (9 months on; 3 months off). Coal consumed was up to 13 tons a day. The engines operated until 1980.

Perhaps the Ambridge engines could match that, to supply the West Midlands  with its water.

Neil Carney’s model is a delight of detail. As well as the triple engine itself and its pumping arrangement the staircases are finely executed as is the control panel. The model is nicely  finished  and lined, and the flywheel looks really authentic. The turbines that replaced these engines were tiny in comparison, but lasted just a fraction of the life of these behemoths. That’s progress?

*For the benefit of readers from outside the UK.  The Archers is a long running daily radio programme on the BBC about a fictional farming family and their life in Ambridge. It is actually the world’s longest running soap opera, first broadcast in 1950.