After wowing the world by building a huge subway network in a short period, Chinese rail companies are now facing serious questions about safety standards. Even the government's rail safety bureau has begun blaming subway operators after a series of recent subway construction accidents.

Late last month, government investigators blamed the operator of Foshan metro systems in South China for negligence and misjudgment resulting in the collapse of an under-construction tunnel that claimed lives of 11 project workers in February.

In another incident in July, a train derailed during a test run in Wuhan, injuring three workers. Several cars on the front side of the train jumped the track as the driver applied the brakes.

In Shenzhen, seven power cables and water lines were accidentally cut off during excavation work for a metro line. The subway operator initially blamed incorrect maps on the cable network, but the power company hit back, saying the construction work was "primitive."

Construction crews have cut power cables during subway work 11 times so far this year, according to the railway safety bureau.