The problems were discovered during routine inspections. The construction defects on the seven lines included cracks and leaks on tunnel arches, tilted communications towers and poorly arranged electronic cables, the Chinese news portal eeo.com.cn reported on Tuesday.
Other problems were found on five lines currently under construction, including one linking Lhasa and Xigaze in the Tibet autonomous region, which is an extension of the Qinghai-Tibet railway.
The ministry severely criticized some contractors for building with low-quality materials and not using enough iron bars in reinforced concrete.
Media reports quoted anonymous experts as saying the defects might threaten railway safety.
Cracks on the railway tunnel’s arch could cause concrete chunks to break off when a high-speed train passes, destroying the train’s power supply equipment, they said.
A ministry official who spoke to China Daily on the condition of anonymity confirmed the authenticity of the document, saying it was meant to be circulated inside the ministry and to relevant parties.
He said the ministry is paying great attention to quality issues, and has organized regular inspections on railway construction and operations.”
Good news: in the past such information would not have seen the light of day; bad news: too many defects in a key transport and communications system.