The 71-year-old woman and her 1-year-old grandchild did not sustain any serious injuries.
The train derailed shortly after midnight on Monday.
The Moroccan suspect allegedly attacked people on the train using an automatic weapon.
Three were injured after a gunman attacked passengers on a train in northern France.
The company said it's trying to improve safety in the wake of the deadly crash earlier this month.
The lawsuit, filed in Philadelphia, cited "serious and disabling" injuries from the May 12 derailment that killed eight people and injured more than 200 others.
The engineer claims he "has absolutely no recollection of the incident or anything unusual."
More than 24 hours after an Amtrak train derailed and crashed in Philadelphia crews recovered another body.
At least seven people were reported killed and dozens injured as a result of the derailment Tuesday night.