Duronto is overtaken only boecoz of time table, most of the time the duronto is before time and per TT TN should reach NZM before duronto and also the duronto has to be berthed at NZM whereas TN has a 2 min halt so a platform should be vacant to receive the duronto, as to why TN overtakes other trains, that happens only when others are late BUT being a highly clogged section any train that gets late between GWL and NDLS has to pay the price of overtake due to the tight slot timings. Any train to NDLS gets more priority over train terminating at NZM as the preference is to clear the trains from NZM as soon as possible, the ideal solution is to have more platforms at NZM, which is remote.