I think the moves will start when the is back to full service. And the R179s are the real odd-balls that restrict fleet interchange between the . The 10-car R179s cannot run on the until the 8-car R179s are gone due to likely train crew confusion as to whether they're operating a 10-car or 8-car consist. Especially now that the 168 St train trips from the morning rush get changed over to trains for midday service, then back to the line for the Rockaway Park trips in the PM rush, the R179s cannot run on those specific trips, and there has to be specific R46s available to be taken out of service at 168 St to change over from the . Also the Euclid Av trip in the morning from 207 St cannot run R179s assuming that that particular train also gets changed over to a train at Euclid Av for midday service.
At least now that the is running R211Ts, technically the R211s can run on the 168 St trips out of Far Rockaway and swap over to the , but knowing operations and dispatchers from the will not send the R211s on those trips either (opting to just use the R46s).