They need to do SM at destination stations and require turnaround time of 10 hrs to take care of lates of any. Dhanbad cannot be extended as it requires 6 hrs running and 8-10hrs turnaround time at TVC. While Tatanagar Erkm stays for 26hrs un Erkm can be extended to TVC. Even if 9hrs in running time still has 17hrs left for PM. For any train TVC need to fund slot for SM. SM is done when ine way distance is more then 2000km.