The Sydney Morning Herald | Sydney Harbour Tunnel reopened after 'momentary' power cut causes closure The Sydney Morning Herald The Sydney Harbour Tunnel has reopened to traffic, nearly two hours after a "momentary" power outage at two substations on the lower north shore caused the tunnel to be shut down. The tunnel was closed in both directions about 10.10am on Monday due to ... Traffic chaos as power cut closes tunnel Sydney Harbour Tunnel closed due to power failure Sydney Harbour Tunnel has reopened |