Get a window seat (preferably on the right hand side) to see the vast hillside valleys during the beautiful Tunnel section which starts at 'Shrungavarapu kota'.
This train even has one good-old "First Class" coach if would like to travel in privacy with your wife/family. Majority of passengers get down at Araku.
Beautiful Places along this route (called the 'KK line' or Kothavalasa - Kirandul line)
1)...
more... Araku (Hill Station + Borra Caves)
2) Jagdalpur (Chitrakut Waterfalls, Kanger Valley National park - Tiratgarh Falls + Kotumsar, Kailash Caves)