BKSC route is currently the fastest route as 12439 departs 45 mins later compared to 12453 and 1.15 hour if 12877.
Besides even when LAD comes into existence a max of 1.5 hour will be saved so 12453 will depart at 6:40 pm. So I dont think
Railways should opt to lose BKSC, KQR & Gaya passengers just to save 45 mins of RNC.
While...
more... there is no doubt that 12439 has always been economically more profitable than 12453 in terms of higher occupancy