Bhai saab not possible...
Already this train runs with small rake then also around 70% to 80% occupancy ....maximum is intermediate daily passengers from say ASN TO KGP, ASN TO MDN, ADRA TO KGP, BQA TO MDN, etc.....few KGP TO HLZ also ....few are end to end travelers in ASN-HLZ Exp....
Now if you run 2 trains in same direction with 15 mins of gap between them then occupancy of both trains will fall and that will be unfeasable ...
Slip...
more... attachment/ detachment time waiting time at KGP or PKU is not possible
..in both stations blocking plstform for 15 mins for loco add/ detach with main reck not possible...
This 15 mins extra time to attach/ detach slip portion from main reck will affect the full TT of the train...
With a gap of 15 mins ....slot of 2 trains specially from kgp to pku needs to be seen because in morning time kgp to pku quiet busy ....
Technically not at all possible to run 2 trains ASN-HLZ Exp and ASN-DGHA Exp Daily with a gsp of 15, 30, mins or 2 hrs also.....
Reverse TT possible but for that pitlines at Digha stn and few new crossing on digha single line needs to be constructed then only possible...