The deadly train collision in Shandong province Monday was caused by human error, initial investigations show, the Xinhua News Agency said.
Excessive speed might be one of the factors.
Some investigators said train T195, from Beijing to Qingdao, was traveling at 131 kph, far in excess of the speed limit of 80 kph.
Vice premier Zhang Dejiang (C), talks to rescue workers on Monday in Shandong Province. [China Daily]
Authorities have ruled out the possibility of a terrorist attack.
Chen Gong, a director, and Chai Tiemin, a Party secretary of the Jinan railway bureau have been sacked, subject to further investigation by the Ministry of Railways, Xinhua said.
Train T195 derailed at about 4:40 am yesterday.
The incident occurred near the village of Hejiacun, which lies between Zhoucun district and Wangcun railway station in the suburbs of Zibo, about 70 km east of the provincial capital Jinan.
Ten carriages toppled into a ditch.
The train was then hit by train 5034, traveling from Yantai to Xuzhou, causing the latter to veer off its tracks too.
By press time, 70 people had been confirmed dead and more than 400 injured.
The death toll could rise given the large number of the severely injured, the ministry said.
A number of other trains were subsequently delayed or had their schedules amended as a result of the incident.
Officials from the Supreme People's Procuratorate have been sent to the scene to conduct detailed investigations.
The accident is believed to be one of the worst in the country, which relies heavily on rail transportation.
"It is appalling," Ji Jialun, a professor at Beijing Jiaotong University, said.
"It is very rare to see so many deaths in a railway accident."
The accident could have been avoided if it was caused by human error, Ji said.
"If, as is suggested (human error), this is a grave breach of railway operation rules.
"Someone has got to be sacked. China's railway regulations are very strict, if people operate according to the rules, this accident should not have happened," Ji said.
The accident occurred as a new schedule on the Jiaoji line was due to be put into effect yesterday.
In January, a high-speed train ploughed into a group of railway workers in the same province, leading to the deaths of 18 people.