As far my knowledge,trains coming from Delhi/Bihar/Jharkhand/HWH/North East has an RSWL for NGP/VSKP but carries passenger with GNWL till BZA.Also BZA is at a convenient distance from the Southern Parts of the country,so that even if tickets are not AVL from BZA,they can always go for Originating Booking.Please check ur facts before replying.