Most of those transfers are Williamsburg to Midtown transfers for riders who prefer the to the ... almost nobody is going from far South Brooklyn to Williamsburg via Canal St. Anyone who wants to go from South Brooklyn to FiDi should transfer to the .
All stats for empty trains. Note that the newer trains have a higher max capacity, so the difference increases when fully loaded.
R160 weight per car: 85,200 lb. Weight per train: 852,000 lb. The R143 is about 2000 lb lighter per car. The R179 isn't something I could find.
R68/A weight per car: 92,720 lb. Weight per train: 741,760 lb. R46 is a touch lighter.
R32/A weight per car: 79,930 lb. Weight per train: 799,300 lb (post rebuild)
R32/A weight per car: 70,000 lb. Weight per train: 700,000 lb (as delivered)