We’re not sure about anything besides what it’s replacing yet, but the reasonable answer would be no since as far as we can see, the MTA wants everything to be as standardized as possible. Examples: R143, R160, R179, R211 are all 60 feet and can run on the Myrtle, Jamaica, and Canarsie lines since they’re short enough to not clip other trains, and they can have cars removed from their sets to put them into passenger service on the mentioned lines. We won’t see the MTA experiment for a while…