Better to start it from VSKP only if you want to route it via-Rayagada.
No one below RJY will spend 3600 rupees approx for 25 hours of journey when you can go in AP exp with 1800 rupees with almost same time.
From BZA TN Rajdhani take 22 Hrs and this train takes 26.30 hours.Moreover if you want maintain 80+ Avg speed running on Trunk route is better option than sub-arterial routes.