Not easily. Think the MTA has done studies on such, maybe as far back as the 80's, 90's last time there was a rash of incidents. Some railsystems have them but they were designed from the start.Easily solved with putting plexiglass barriers onto platforms like they already have in many airports.
But NY's subway is multi train car sizes, lengths and platforms. Think the cost would be in the dozens of millions if not $100+ mill.