Spotted this train with different rakes on different days. 1 rake has 1-2 duronto liveried coaches. Similar rake I once saw in AII Shatabdi. I think there is 1 extra LHB rake in NR used as spare rake for LKO/ASR/KALKA/DDN/BPL/AII shatabdis one by one. All these shatabdi's are daily and get only approx 7 hrs maintainace time @ NDLS. SO I think 1 spare rake is there...