Help dating this photo

Clark Propst

I figure the best way to date this photo is to asked when the NYC did away with their S prefix? Sure appears the closest hopper's number starts with an S? The hopper in front of it is a panel side. A 1930s aerial photos shows the stock pens, they are gone in a 1950s aerial.

Any help would be greatly appreciated,
Clark PropstĀ 


I don't have an exact date ,but the "S" prefix was no longer used by the mid 30's. Actually though that hopper
looks more like the very late 30's and later NYC offset side hoppers.The 1920's era offset side hoppers that would have had "S" numbers also would have had vertical shaft/horizontal wheel hand brakes.
Larry King