Zhou Yimin, a deputy chief engineer at the ministry, told the financial magazine Caijing that the trains' maximum operating speed should be 300 kph rather than the originally targeted 350 kph. Railways Minister Liu Zhijun, who was dismissed this spring amid an investigation into unspecified corruption charges, insisted on claiming the world's best technology for all aspects of the showcase high-speed rail program, Zhou told Caijing.

Liu demanded higher speeds for the 215 billion yuan ($32.5 billion) Beijing-Shanghai railway to 380 kph despite knowing that the contracts for the foreign-designed cars being used called for a maximum of 300 kph, he said. "What he wanted was buying a train with a top speed designed at 300 kph but making it run at a speed of 350 kph," Zhou said.

Liu was the public face of the high-speed rail program. No details have been released about the allegations against him, but news reports say accusations include kickbacks, bribes, illegal contracts and sexual liaisons.

As the ruling Communist Party approaches the 90th anniversary of its founding, on July 1, it is seeking to burnish its image for graft-busting.