Samuel Rivera announce the lawsuit at the Burke Rehabilitation Hospital in White Plains, where he has been for three months undergoing treatment.
The December 1 crash near Spuyten Duyvil left Rivera, who was off-duty, a quadriplegic.
Four people were killed and another 100 injured.
Samuel River's lawyer says Rivera, who was heading into Manhattan to spend the day with his son, has extraordinary medical needs from his injuries.
It was the second lawsuit to be filed over the derailment. Last Friday, Eddie Russell, a retired police officer, sued Metro-North for $10 million.
The Metropolitan Transportation Authority, which runs Metro-North, declined to comment on the lawsuits.