DD has competition from volvos which offers less fares compared to DD and completes end to end in 3.5 hours.
If an AC express is introduced then AC coaches in nizamuddin intercity can be replaced by SL . An AC express with convenient timings can actully attract the fliers .
INDB BCT duronto is not popular because its timings are not good at both end complared to avantika. Had it got 8 pm TO 8 AM schedule this would have got much better patronage.