China plans to build 42 high-speed railway lines by 2012 in a massive system overhaul, part of its efforts to spur economic growth amid the global downturn, state media have reported. China hopes to have added 13,000 kilometres (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 kilometres per hour, the report cited Zhang as telling a science conference in the southwestern city of Chongqing. The country would then in three years have four north-south and four east-west artery high-speed rail links across its vast territory, the report said.