Just for everyone's enlightenment, here are the definitions of a public place in the New York State Penal Law, section 240.00, sub 1.
1. "Public place" means a place to which the public or a substantial group of persons has access, and includes, but is not limited to, highways, transportation facilities, schools, places of amusement, parks, playgrounds, and hallways, lobbies and other portions of apartment houses and hotels not constituting rooms or apartments designed for actual residence.
Sub 2 defines a transportation facility
2. "Transportation facility" means any conveyance, premises or place used for or in connection with public passenger transportation, whether by air, railroad, motor vehicle or any other method. It includes aircraft, watercraft, railroad cars, buses, school buses as defined in section one hundred forty-two of the vehicle and traffic law, and air, boat, railroad and bus terminals and stations and all appurtenances thereto.
So you see, a railroad station, platform or train for that matter is a public place as defined by the NYS Penal Law. It's no different than a public street.