I guess probably this is also one reason where RB has issued notification for standardisation of rakes. In case of very less TAT, they can still ensure that train departs on time using rake of any other train. But easier said than done. Ultimately passengers are sufferers. I always find the example of LTT-CBE/CBE-LTT which continuosuly used to run late for months together and then finally CR had to cancel running of one service to bring all of them back to track