I once went to GHY [and was pleasantly surprised by the quality and diversity of non veg items on offer in the city] via 3A of GTNR-KYQ Express. It was the only time I was automatically upgraded from SL to 3A. I once came back from Tripura via 3A of Rajdhani[Agartala Rajdhani] and it was one of the worst trips ever.
Though I did take a ride in the Agartala DEMU and went to a local station just for the sake of it in the heavy monsoon season.