In Guntur division, Repalle has higher passenger traffic, as compared to Nandyal. But, Repalle also doesn't have any Intercity train, to any of the city.So, introduction of train on Indian Railways, is dependent on various factor(s), which include but not limited to - Commercial Justification, Operational feasibility, Availability of rolling stock etc.Regarding congestion in Guntur-Nandyal section, you may please refer Indian Railway's National Rail Plan ( click here ) Page No. 400 to 403, where in Guntur-Guntakal section falls under HUN8, which is planned for Doubling with Automatic Signalling.

If there is a constraint, it will be communicated (irrespective to the place/division).Even, while replying to some of the representations made by Hon'ble MP, Kurnool on 25.09.2018, General Manager/South Central Railway had replied that - Due to lack of Primary Maintenance facilities at Kurnool, it is not feasible. It was also replied that maintenance slots at Tirupati coaching depot are saturated.But later, Primary Maintenance of Padmavathi Express was shifted to Tirupati (from Secunderabad).I believe this will help you in understanding the case with other places & divisions (KRNT/HYB) as well, while you comment about Nandyal/Guntur division.Moreover, if you are so confident...

Notification

During Hon'ble MP's meeting with General Manager, South Central Railway (at Vijayawada) on 25.09.2018, Mrs. Butta Renuka (then Hon'ble MP, Kurnool) had also requested for new train, for which railway's remarks are pasted for your quick reference,This will help you further, in better understanding.

Political push...!!!If so, please refer the reply given by Hon'ble Railway Minister Sri. Piyush Goyal, for the question raised by the MP regarding plans to increase connectivity between Visakhapatnam and Kurnool, any trains proposed between 3 capitals of Andhra Pradesh.I believe, this reply helped in clearing your myth.