>>>>>Isn't it still used for freight as well?<<<

I can't say for sure whether this particular line is still used for freight. If anything, it's just for eastern Long Island - and not Boston-bound (via Stonington, CT) like in the 1800s. In all my trips to Greenport, I've never seen anything but ferries pulling in and out of the harbor adjacent to the train station. Other than daytrippers to Greenport, I think the station is used mostly by people headed to Shelter Island. I wonder what THEY would do without train service out there?