Via BJU-2275, SPJ-2453, PPTA-2436 Kms. Marginal Km/Fare Diff not Huge.
DBRG-GHY-HJP: BJU is fastest & PPTA few mins over SPJ!! Agartala Raj run is approx same for LMG-HJP, as compared to other Raj & is slowest for GHY-HJP!! For DBRG-BSB/DDU, BJU version is still fastest, thanks to diversion!!
There is no much run diff for DBRG-GHY/PPTA/BSB/DDU to hinder travel preference till these stations & then as you said, it get max pax for NDLS past KIR!! I dont find it remain empty in Assam & afterwards!!
PS:...
more... When weekly Raj started via LKO, i guess the same like you but then it become Bi & Tri-Weekly & now daily!!