If silence is the space within which music exists, then perhaps noise is the stuff that makes stillness possible.
Bryan Crump took that approach to this week's sonic Moment of Calm. It's a 1958 recording of the Wellington to Auckland Express charging through a cold night just south of Waiouru.
It was one of many recordings of New Zealand steam locomotives Dawson Wilkinson made as the age of Kiwi steam drew to close, edited by Peter Mellor into the splendid record you see below.
A KA class locomotive pulls the Auckland, Wellington Express into National Park in 1965. Credit: W W G Pryce. Photo: Bryan Crump
Sure, the stuff in the middle is pretty raucous, but listen to the end and you'll hear the whistle blow and echo around the high country hills - we reckon that might still the soul.