Yes i agree SRC-ANVT takes a longer route but its travel time from SRC to ANVT is 22hrs 40 min, which is less than or almost equal u can say to one of the important train to Delhi side from Kolkata i.e. Netaji exp between HWH to DLI travel time is 23 hours.
On the otherhand, the travel time of HWH-CSMT Superfast Mail via ASN is more than even SHM-LTT Kurla exp which is one of the slowest Express train between HWH and Mumbai and it is only a Express train not even a Superfast train like Mumbai Mail via ASN.
I...
more... agree Durgapur passengers needs a train to Mumbai. But for them you can demand increase in frequency of ASN-CSMT Exp , why you want to regularise this slow SDAH-LTT Spl?