A person was taken to Stony Brook University Hospital after being reported injured at the Port Jefferson Long Island Rail Road station.
The Metropolitan Transportation Authority suspended service on the Port Jefferson line of the railroad for about three hours while police investigated.
MTA police received a call about the injured person at about 7 a.m., said spokesman Aaron Donovan. The extent of the injuries or whether the person was struck by a train was unclear, though the person was alive when taken to the hospital.
According to an alert on the MTA website, service was halted in both directions between Port Jefferson and Stony Brook.
At least three trains -- two eastbound and one westbound -- were canceled.
Service was restored with some delays by 10:11 a.m., Donovan said, and completely restored about an hour later, according to the MTA website.