As many as 14 people were injured when a driverless train in suburban Tokyo went in the wrong direction and crashed into a buffer late on Saturday. The train hit the buffer stop at Shin-Sugita station after travelling the wrong way for about 65 feet, Akihiko Mikami, president of the Yokohama Seaside Line Co, said, according to AFP. Yokohama Seaside Line Co operates the route.

The train was travelling at a speed of 6 km per hour, and was supposed to depart the station, but instead moved backwards and hit the buffer stop, The Japan Times reported. Authorities said it was carrying about 30 passengers.

The unmanned train system is operated by a computer. The computer determines the train’s speed based on data gathered from all other trains travelling on the line. Saturday’s accident was the first in Japan involving an automated train since 1989.

The cause of the accident is not yet known. Mikami said the staff had found no technical problems when they checked the train’s brake system on Thursday. The Yokohama Seaside Line Co has temporarily shut down the the Kanazawa Seaside Line, which connects Shin-Sugita and Kanazawa Hakkei stations.

An investigation has been launched into the incident. Officials from the Japan Transport Safety Board are examining the train cars at Shin-Sugita Station on the line. The Japan Times reported citing sources that the officials are considering filing a charge of professional negligence.