The R211 is a future new technology (NTT) New York City Subway car to be built by Kawasaki Heavy Industries for the B Division and the Staten Island Railway (SIR). They will replace all remaining R32, R44 (SIR), and R46 subway cars. The order is split into three parts: R211A and R211T cars for the subway and R211S cars for the SIR. The R211Ts will employ open gangways between cars, a feature not present on current rolling stock. The base order consists of 535 cars, with options for up to 1,077 additional cars.
Source: R211 (New York City Subway car) – Wikipedia
These will replace the oldest cars in the system on the A, etc.