There are 6 trains originating from TVC terminating at NDLS/NZM ( including daily, weekly) & 3 additional trains which cross Delhi for other destinations ( CDG, ASR, ) so about 9 trains in all. This has been one reason not to extend Mangala which is justified.
Given that Mangala has been converted to LHB & there are sections in NR where 130km/hr mps is implemented, they can try and look at going back to its old TT of 9am departure from Delhi which is a bit more convenient.
By...
more... reducing some slack in KR section and SRR-ERS section, its arrival at ERS can remain the same what it is now. I think easily 2/2.5 hrs speed up is possible. Hope they speed up in the new time table.