A train using ET route which is already busy why railway always think about busy route which have high amount of train while via NGP BSP ROU RNC DHN route is not so much busy they can run train in this route because of no trains towards Gaya using this line it will hit success if this route is choosen, PS i am not creating any doubt to ET route which is given already success to railway i am just giving a opinion a train can hit success to those route which have not connectivity to directly Gaya.