electrical fault on a Northern Line train near the Sydney Harbour Bridge strands 4,000 passengers on Sydney's CityRail train system for nearly three hours, and causes substantial delays during the evening rush hour. 16 March – Senator Santo Santoro resigns as Minister for Ageing following a scandal involving his ownership of shares in a company related to his portfolio. He resigns from the Senate on 20 March. 18 March – More than 200,000 people walk across the Sydney Harbour Bridge to celebrate its 75th anniversary. 23 March – Three people are killed when three trucks and four cars are involved in a major collision and explosion in Melbourne's Burnley Tunnel. 23 March – The PlayStation 3 games console is released in Australia, exactly a year after the Australian release of Microsoft's Xbox 360. 24 March – The Australian Labor Party and Premier Morris Iemma are returned to power with a reduced majority in the 2007 New South Wales state election. Peter Debnam resigns as Opposition Leader & Barry O'Farrell is elected leader on 4 April. 26 March – Australian Guantanamo Bay detainee David Hicks pleads guilty to a charge of providing material support for terrorism before a United States military commission in Cuba. 28 March – Four people are killed after a private charter boat collides with a Sydney Harbour ferry. 29 March – New South Wales Police arrest three people, including an Australian Army captain, for alleged involvement in the theft and distribution of M72 LAW rocket launchers to criminals. 31 March – Earth Hour, in which Sydneysiders were encouraged to turn off their lights between 7:30 pm and 8:30 pm, takes place. April 2 April – The Bureau of Meteorology issues a tsunami warning for the east coast of Australia after an earthquake in the South Pacific Ocean is detected. Precautions are taken, such as the suspension of Sydney Ferries services, but Australia is unaffected. The tsunami, however, causes devastation in the Solomon Islands. 10 April – Four elderly residents of the Broughton Hall nursing home in Melbourne die after a gastroenteritis outbreak at the home over the Easter weekend. A fifth resident dies in hospital on 16 April. 19 April – Prime Minister John Howard announces a report which states that unless significant rain falls in the Murray-Darling Basin within the next six to eight weeks, Australia will face a major agricultural crisis with no irrigation allocations