PGT generally travel to Nedumbassery (Kochi) or Karipur (Kozhikode), which are well connected to all major domestic and international cities. Also Coimbatore is there.
For Salem, Erode conveniently one can travel to Chennai Central and take metro to airport. Lot of trains are running - Cheran, Nilagiri, Yercaud, SA MS SF, Kovai apart from many Kerala originating trains like Alleppey, TVM mail, Westcoast, MAQ mail etc.
Also, Devanahalli does not have facility to park a train for whole day.
Better...
more... to extend to DVG or Shivamogga.
If done, this will be the first train from SR to cross Tumkur line.