BEIJING, September 10, 2009 (AFP) - China plans to build 42 high-speed railway lines by 2012 in a massive system overhaul that is part of efforts to spur economic growth amid the global downturn, state media have reported.

China hopes to have added 13,000 kilometers (8,060 miles) of fast lines to its massive rail network in three years, the China News Service said Wednesday, citing Zhang Shuguang, deputy chief engineer at the railways ministry.

The tracks would be capable of handling trains running at up to 350 kilometers per hour, the report cited Zhang as telling a science conference in the southwestern city of Chongqing.

The country would then have four north-south and four east-west high-speed rail arteries across its vast territory, the report said.

Construction on the third east-west artery has already started and will link up with the Beijing-Shanghai high-speed rail line, which is due to become operational next year, in the eastern city of Nanjing, it said.

The new tracks would mean the travel time from Beijing to the central hub city of Wuhan would be more than halved to around four hours, it added.

The country has developed a "major breakthrough" that will enable high-speed trains to run on both fast and normal-speed tracks, Zhang said, according to Wednesday's Chongqing Times.

"China has the most advanced high-speed rail technology in the world," Zhang said, adding the country's fast rail network would have the capacity to carry seven billion passengers a year between 2011 and 2012.

A train that can travel at 500 kilometers per hour will be tested at the end of 2010, he said, according to other local media reports.

Beijing has said it will invest at least two trillion yuan ($293-billion) in railway construction over the next three years, as it struggles to boost its export-dependent economy.

China's railway network is already one of the most extensive in the world, but it has come under pressure as the nation's economic boom has given many of the country's 1.3 billion people more opportunity to travel.

By the end of this year, China will have a total of 86,000 kilometres of railway lines, second only to the United States, officials have said.

The nation aims to have 120,000 kilometers of track laid down by 2020, they said.