The steam engine was the heart of the factory. It was commonly known as "the mule", as it operated all the machinery in the industrial unit. The engine on display is not originally from the factory. It was built in 1897 by the Maquinista Terrestre i Marítima company and used at the Ponsa del Poblenou silk scarf factory in Barcelona.
The original steam engine from this factory has not survived but was sold for scrap in 1915 following the introduction of electricity. The photographs show it was a double-expansion steam engine, using steam twice, at high pressure and at low pressure.