You said "Kankavali will get no additional trains halting at the station". Ok we agree its right but the new train is going to start "Ratnagiri Madgaon Passanger, will that will also not halt at Kankavli?
Kankavli has proved to be one of the Main stn, the only stn in India to have Bio-Tiolets with Chiplun, most of Superfast Trains halt at Kankavli