Hundreds of ambulances, doctors, nurses and rescue personnel were sent to the scene to rescue passengers and pull out bodies.
Biswajit Sahu, Chief Public Relations Officer of East Coast Railway, said that a "human error" had led to the collision, caused by "overshooting of signal" by the second train.
He added that 33 trains have been cancelled and 22 others have been diverted following the accident. Railway officials expect the affected track to be cleared for traffic to resume by Monday evening.
Andhra Pradesh's Chief Minister YS Jagan Mohan Reddy's office said he would visit the site of accident on Monday. The minister has also announced financial compensation for the victims.
India has one of the largest train networks in the world with millions of passengers using it daily, but a lot of the railway infrastructure needs improving.
Sunday's accident comes just months after a devastating crash involving three trains killed 292 people and injured thousands more in the eastern state of Odisha.
The country's top detective agency arrested three railway employees in connection with the railway accident, which was the worst in 20 years.
