The world's largest functioning triple-expansion steam engine is an unbelievably massive beast of a machine. For 77 years, the 19m high engine -- weighing in at 900 tonnes! -- powered gigantic flywheels and crankshafts that pumped millions upon millions of gallons of water from west to north London. It was decommissioned in 1980, but brought back to fully functioning life by a team of retired volunteers who care for the oversized apparatus like it's one of their own.
This "Triple" was one of two installed in 1927 in a custom-built engine house, the realisation of an exacting two-year production process by pump manufacturer Worthington-Simpson. The pair worked in tandem until they were taken out of service over three decades ago, and lay dormant until a team of volunteers took on the task of restoring one to its former glory (the other was left as-is, and visitors can climb to the top on a guided tour).
It's incredible seeing how small the men look in comparison to the gigantic gear they're meticulously caring for, because all of a sudden it's clear that this massive thing is, in fact, composed of all kinds of bitty elements working together. But to hear them speak about it, this is not just an amalgamation of moving parts; it's an imagination sparker, something that breathes and "leaps about" with character. "It's a monster," one of the men says with a smile.