While the train itself is decent (though maintenance could be better), if you are travelling to/from Itanagar and taking this train, you can be expected to spend quite a lot on taxis from/to Naharlagun station as this train arrives/leaves there at odd hours. The scheduled arrival of 9.40 pm of the Shatabdi at Naharlagun is very late for those parts and the station itself is situated in a rather isolated area. I ended up paying more for the taxi ride to Itanagar from Naharlagun station than I did for my train ticket.
The...
more... route is quite scenic but if you want to take this train for the scenery, you need to take 12087 Naharlagun - Guwahati and not the Guwahati - Naharlagun train; it gets dark by 5-5.30 pm and you will not be able to see anything if you take the Naharlagun-bound service.