Out-of-control train carriage ran 1.5km through Sydney Metro tunnel in one of several safety incidents

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A 30-tonne railway trailer transporting equipment on the Sydney Metro project ran uncontrolled for more than 1.5km through the half-built tunnel between Marrickville and Waterloo in July, Guardian Australia can reveal.

The only reason workers weren't killed, according to those on site, was because it happened on a Saturday at noon, when they were on their break.

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