May be due to no LC time at GTL they taking LC at GNT only and also their might be proper LSA can happen at GNT as per its arrival and departure at GNT. Also their might be not gettin enough power in this section to run Eloco for which another deserving train can be run with Eloco as this train anyhow have to get LC at GTL for Dloco.My words all are assumptions better some local member can put light on this isuue.