PHILADELPHIA (CBS) — A lawsuit has been filed on behalf of one passenger injured in Tuesday’s SEPTA train crash in Upper Darby.

In the complaint, Derrell Robson says he was knocked unconscious and suffered a head injury when the Norristown High Speed Line train slammed into a parked train at 69th Street Station.

NTSB Investigating After 33 Injured When Train Crashes At 69th Street Terminal

Attorneys Tom Kline and Robert Mongeluzzi are representing Robson.

“We believe it was important to get his case in the suit because his case is a representative case and one which will carry the ball forward immediately,” said Kline.

Mongeluzzi added, “There is no excuse when you crash into another train. That is clearly the failure of the transportation organization SEPTA, either mechanically, by operator error or by both.”

The NTSB is investigating what caused the crash.

Federal officials say 33 people were injured, including the train’s operator.