I will give tips only when I am sure of it. Don't misunderstand me. I have personally purchased vegetable pulav from Rayadurgam station while traveling in this train to Bengaluru. And regarding Pavagada many private buses will be available from Challakere which I have witnessed. KSRTC buses are not available in this route. There are some private buses from Ballari to Pavagada via Challakere. You can re-check through other sources regarding private buses from Challakere to Pavagada.