An investigation into a deadly bullet train crash in China has found that faulty signalling systems and mismanagement were mainly to blame, reports said on Friday, though the accident was triggered by a lightning strike.

China’s State Council, or Cabinet, is reviewing the findings from the probe into the July disaster, which killed 40 people, injured 177 and prompted checks for the entire bullet train program, the Caijing financial magazine and other reports said.

The lightning strike caused one bullet train to stall and a sensor failure allowed a second train to keep moving on the same track and slam into it. The Daily News newspaper cited experts warning that the faulty signaling systems are still in use at dozens of stations along high-speed rail lines.

The draft report for the investigation was due to be finished by Thursday. Caijing cited one of the experts participating in the probe, Wei Zhen, as confirming that it had been completed. But it said Wei, a professor at the Hefei University of Technology, did not reveal details of its findings.

The Daily News, reiterating earlier reported findings, said the crash occurred because a signal that should have turned red when lightning stalled the first train stayed green. Railway staff also failed to notice something was wrong.

The Beijing National Railway Research & Design Institute of Signals and Communications Co., which made the signal, has publicly apologised after the crash.

Although the railways are rushing to fix the faulty systems, some experts believe train services should be stopped until all the problems are fixed, the Daily News reported.

It cited an unnamed expert saying that the crash occurred because of an unusually heavy lightning storm and that the signals normally should work. Whether they would be replaced would depend on a variety of factors, including cost, it said.

“There were also many problems with management and coordination and some of the workers are not well qualified,” the Daily News cited the report as saying.

However, assigning responsibility for the mismanagement is proving controversial it added.

The Wenzhou crash was a heavy blow for the showcase high-speed railway program and has invigorated public criticism over the costs and speed with which it has been rolled out.

It also precipitated monthlong inspections of dozens of projects and 3,700 miles (6,000 kilometres) of bullet train lines.

China has 13 high-speed railways in operation, with 26 under construction and 23 more planned, although approvals of new projects were frozen following the Wenzhou crash.

Earlier plans called for expanding the network to 10,000 miles (16,000 kilometres) of track by 2020.

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