This horizontal, single-cylinder gas engine runs at the entrance of the Ansom Engine Museum in Poynton (Cheshire, UK). It was made by the National Gas and Oil Engine Company early in the 20th century. (To clarify, gas refers to natural gas and not gasoline.) Alas, I cannot remember where it originally worked but I think that it was at a reservoir.
Nikon Zf, 35mm f/1.8S.