Harbour Tunnel snarl-up triggered by drainage maintenance failure The diesel spill that closed the Harbour Tunnel for more than an hour on Thursday morning, forcing long traffic snarls right through the city's northern suburbs, was apparently caused by an overnight maintenance failure on the tunnel's drainage system. In one of the worst recent mornings for commuters trying to get to the CBD, queues of traffic extended north from the city deep into the Lane Cove Tunnel, along Victoria Road and into the northern beaches. The trigger was the closure of the Harbour Tunnel just after 6am. The tunnel was closed after a truck struck a metal plate in the gutter of the tunnel's southbound corridor, puncturing a tyre and ripping off the fuel tank, which split open. Harbour Tunnel general manager Bob Allen said the plate was a temporary measure while some of the tunnel's 20-year old drains were being replaced. "It appears that a temporary repair last night wasn't as effective as it should've been," he said. The clean-up inside the tunnel. Photo: NSW Police Force All I want to do is say sorry to the people of Sydney. Mr Allen said it was fortunate the truck was able to stop in the tunnel's breakdown lane after its tyre was punctured. More than 200 litres of diesel fuel spilt along 300 metres of the tunnel, forcing authorities to close all southbound traffic while it was cleaned. The tunnel was eventually reopened just after 8am. But congestion continued to build through the northern half of the city. On Victoria Road, one of the alternative routes into the city, traffic backed up to the Gladesville Bridge. On the northern beaches, there were delays on Manly Road through Balgowlah until about 9.30am, the Transport Management Centre said. Commuters who ditched buses and cars for trains and ferries were also delayed. There were also major delays on the Airport & East Hills Line and South Line after overhead train wires came down at Campbelltown. The opposition rounded on this as the latest in a succession of peak-hour snarls. The opposition spokesman for roads Ryan Park called for a refund of the Harbour Bridge toll. Roads Minister Duncan Gay apologised to motorists and said an inquiry into what went wrong in the tunnel had already started. "As a small measure of compensation, the tolls on the Harbour Bridge were kept at $2.50 until 9.30 instead of the usual $4.00," he said.