A number of major mainland state-owned enterprises (SOEs) have been ordered to conduct internal investigations into claims that corruption might have affected up to a dozen railway projects.
Construction problems have surfaced recently in many rail projects across the country, according to China Economic Net, a mainland business news portal.
Regulatory authorities have ordered the companies to fix problems on 12 rail lines. The firms have also been temporarily banned from bidding for further railway contracts.
The 12 problem lines include the Wuhan-Guangzhou high-speed railway, which will link up with Hong Kong in 2015; and the NingboTaizhou-Wenzhou high-speed railway, where a deadly high-speed-train crash occurred in July last year.
Zheng Tianxiang, a transport professor at Sun Yat-sen University in Guangzhou, said the pace of high-speed-rail development had been too rapid, 'so there will be quality problems'.
'Systemic problems and corruption have not been resolved. With inadequate supervision, it's easy for problems to arise,' he said.
Richard Di Bona, who runs a Hong Kong transport consultancy, said it was likely that quite a few of the problems dated back to the regime under former rail minister Liu Zhijun.