The accident occurred at Naagaran minutes after the train left Ramannapet railway station at 4.12 am. Officials said a small culvert caved in due to surge of water from a breached tank and washed away the 120-metre length of rail track. The Repalle-Secunderabad train, with about 2,000 passengers on board, ran straight on to the hanging track, about 15 feet from the ground.

Over 100 bodies have been recovered even as personnel from the Army and the Rapid Action Force as well as locals continued the rescue effort. The driver of the train was among the dead.

Locals said a tank in Yellanki village breached around midnight due to heavy rain. Fearing inundation, villagers of the adjoining Gollepalli village dug another bund, letting water into the small rivulet, which was dry for three decades.

The six-metre stone culvert could not withstand the water pressure. Once the stone structure gave way, the track bed too was washed away.

Officials said this happened between 2 am and 4 am as a special train on its way to Bitragunta had crossed the culvert at 1.15 p.m., adding that casualties were high as the passengers were sleeping and had closed all windows and doors due to rain and chilly winds,

Water entered two general compartments converting them into virtual death traps. The general compartment 1, which turned into a mangled iron heap, is yet to be reached by the rescue teams. By the time the locals reached the spot, an hour after the accident, over 100 people had climbed the capsized bogies and were waiting for help. By the time railway, police and Army officials arrived, those in the capsized compartments were already dead.

Meanwhile, Home Minister Shivraj Patil on Saturday spoke to Andhra Pradesh Chief Minister Y.S. Rajasekhara Reddy and assured help. Home Secretary V.K. Duggal also spoke to Andhra Pradesh Director General of Police Swaranjit Sen.

An Army column was mobilised immediately after the mishap. Eight boats have also been sent to rescue the trapped passengers. The Air Force was ready to make sorties while Naval divers have been moved from Visakhapatnam for the rescue effort.