If you look from ECR's selfish interest, then if they run a train between Dhn and Chennai on regular route, then it would barely cover stations in ECR, only Dhn and CRP post that it will majorly serve SER. And if they run on this extended route, then it is covering max of ECR Dhn and DDU divisions major revenue generating station. Also, no matter how lengthy the route is, since it would connect Hyderabad, Chennai and vidarbha areas of Maharashtra...it would be a sure shot hit