Mysterious recurring noises annoy residents of Salford, Manchester, UK

What are these mysterious recurring noises annoying residents of Salford, a metropolitan borough of Greater Manchester?

The unexplained noises are loud, grating clanks lasting for a couple of seconds at a time but repeated every 15-20 minutes.

This video was recorded by Scott James at around 3:30am on March 29, 2016. According to the uploader, it was really loud, mechanical, lasting only 10-20 seconds and coming from the Eccles area about every two minutes.

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