As per Rail officials this Train shares its Rake and Loco with Lucknow-Raipur Garibrath, and that train has diesel route till Katni thats why LJN-BPL-LJN Garibrath use Diesel loco on fully electrified route. I also think that this is not a proper explanation cz LJN-BJU uses Eloco but its RSA link LJN-JBP uses Dloco.
Same question i have asked for BPL-PBH SF, that why it uses Dloco between BPL-LKO even after having sufficient halt time at LKO for Loco change. But they said that LKO-PBH is diesel route thats why it uses D loco in LKO-BPL strech. Confusing.