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...
more... 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.