In 2A you can get seat availability very easiLY in some trains, like HWH RAJ, PNBE RAJ, POORVA, KK, KERALA, TN, GT, JNANESHWARI SF, LTT DURONTO, etc.
Not like that... few Mail SF trains also get good priority in CR. TN and TG get a very good priority in ET-Nagpur-BPQ section... TG is like Rajdhani for CR..