Passengers on a CityRail train in Sydney narrowly escaped being injured by flying glass last month. The train was going through the Epping to Chatswood tunnel when the pressure caused the window to push out.

About ten people were sitting in the first carriage of the train at the time of the accident. Student Daniel Rosser told local media that a window pane landed just centimetres from one of his friends.

“All of a sudden the door window from the train flew out at such a high speed and flew back down the stairs,” said Rosser. “It was so close, if it had been a peak hour train it would have been so bad.”

“It was an older train and it was air-conditioned so there were no windows open,” he continued. “Our ears popped in the tunnel. The pressure was so great in the tunnel we figure it must have pushed the window out.”

CityRail will now reinforce door windows on its older-style suburban trains to prevent such an accident happening again.

In a statement, CityRail said the incident was rare, but as an added safety precaution, it will now attach metal fasteners to door windows on all K-set carriages.

The AUD 2.3bn (USD 2.1bn) Epping-Chatswood rail link opened last year and has been plagued by problems, including unacceptably high noise levels.

In 2007 it was revealed that Tangara trains would not be operating on the route because of the steep gradient in some parts of the tunnel.