If IR want to do RSA they can change rake zone of a train like 17487/17488 - Tirumala Express. When they wanted to extend Tirumala Express to Kadapa, they made it's RSA with 18517/18518 - Korba - Visakhapatnam Express and made it a ECoR train with PM at Visakhapatnam. So if IR wants they can make changes like this. Anyhow this is just a proposal, let's see what happens