TN and KL trains extension to Chamaraja Nagar is not required. Shorter bus routes are available.To CMNR, Bidar, Bijapur and Belgaum trains should be extended. The problem would be such trains have to pass through SBC, which will be a bottleneck.
As the requirements is for Kerala to Bangalore trains, there are ways to not to bring them to SBC and YPR. Even now ERS band SF can be extended to Shimoga or Davangere. It arrives at band at such an odd timings that people will not prefer it.