An initial autopsy report shows that two 19-year-old women killed when a CSX train derailed in Ellicott City suffocated under the weight of coal that spilled on top of them when the railcars tipped over.
The report from the medical examiner's office ruled the deaths of both Elizabeth Nass and Rose Mayr as accidental, according to Howard County police.
The National Transportation Safety Board is investigating the scene of the accident to determine what caused the train to derail as it passed by the two teenagers, who were sitting along the tracks on the Baltimore and Ohio Railroad when the train passed by them on a bridge.
The medical examiner determined the cause of death was "compressional asphyxia," which occurs when the body is physically limited from expanding the lungs to breathe.
Investigators said the women were buried under roughly 110 tons of coal, about the load carried by a single freight car.
No other details of the autopsy have been released.