Now I got some info regarding the MG section, apart from MTP-UAM. The route is Tiruvarur-Karaikkudi. But between Karaikudi and Pattukottai it is undergoing gauge converstion. There are two daily passenger trains plying between Tiruvarur to Pattukotai, and decided to explore that MG section.May be this route will be functional for more 1 month. After that it will be closed for GC. If anyone wants to join me, please let me know :)