I believe, and it would take much digging in my files to find it, that NYC had some express cars converted from milk cars.  Probably older cars made surplus after more modern steel milk cars came into regular use.  Hence the lack of ice hatches. 

If memory is correct, there may have been an ALCO MODELS brass car and perhaps a Sunshine resin car like this one.  Anyone have the flyer for the Sunshine NYC express cars?

Steve Dolezal