The initial stage of the investigation has shown that control room staff should not have allowed the Transrapid train to begin its journey because a 60-ton maintenance vehicle was still on the monorail test track at the time.

The Transrapid train was traveling at 170 kilometers (106 miles) per hour when it collided with the vehicle on the track in Lathen, western Germany, on Sept. 22.

The driver of the Transrapid train, who was among the dead, should also have spotted the vehicle earlier, prosecutor Alexander Retemeyer from the city of Osnabrück told a press conference.

A recording of a conversation between staff immediately following the crash had revealed a catastrophic breakdown in communication, Retemeyer said.

Control room operators in shock

One of the control room operators is heard to say: "What's happened?"

Another voice replies: "They've forgotten to move the maintenance vehicle out of the way."

The two employees from the control room have not yet been questioned because they are still in a state of shock. They face possible manslaughter charges.

The crash cast a shadow over efforts to market the train, which can reach speeds of up to 450 kilometers (280 miles) per hour.