It may be a coincidence or what ever or may be I'm lucky, I booked ticket in sleeper class from Nagpur to Chennai by 12616 Ndls-Mas Grand Trunk Exp . And all 3 times
8th Feb 2015, 29March 2015 and 27 Oct 2015 in these all three journey I got Same seat which is S4, 36 (LB) which is next to Pantry