This is SWR train. So, it is expected that SWR areas get connectivity to Chennai properly.
I would suggest following timetable: Start from UBL by 1800 to 1830, cover Gadag, Koppal, Hospet, Ballari before 2330 and reach Chennai by 0800. Return start from Chennai by 1930 to 2000, reach Ballari by 0500 and further reach UBL by 0900. If platform issues are there in Central, train can go upto Egmore or even Tambaram.
Another suggestion is to run the train via Anantapur, Dharmavaram, Madanapalli, Tirupati instead of Kadapa. As UBL...
more... to BAY already has connectivity to Kadapa through Hari Priya, running via Madanapalli Tirupati would provide excellent patronage. Even those towns will get a train to Chennai (so far no train running to Chennai in the route). Distance will increase by around 50 KM's but it would not be a problem considering new connection.