Even i thought that it might have taken Tata-Chaibasa route. Tata falls under CKP division not sure if avoiding CKP would have been approved. Also from CTC onwards till TN/KL there are lots of other pass through trains daily ( 3 trains from GHY, bi weekly from Patna, SHM-TVC & SHM-NCJ, HWH-ERS, SRCMAQ). Whereas ROU-VSKP route has two (DHN-Allp, HTE-ERS and another one has got added now at a different time