How come a express with arrival timings at around 23:00 hrs at gannavaram prove helpful to public in view of the airport connectivity and mumbai flight connectivity u quoted as an example.
And to correct you vizag too is having direct non stop connectivity to mumbai for both inward and outward pax.
And as per your own saying - that even vizag dnt have non stop flight to mumbai and bza has one - should not the vizag people be benefitted by asking some vizag bound trains such as godavari,...
more... Nagavali, Garib rath etc a stop at gannavarm rather than the one u asked for.
Some how I sensed a mismatch between ur reasoning and your proposal.