New Delhi - Rescuers struggled on Sunday to pull survivors from the wreckage of a train crash which killed 39 passengers in India, the latest disaster on the country's creaking rail network.Officials were investigating whether Maoist rebels had tampered with the track, after eight coaches and the engine of the Jagdalpur-Bhubaneswar express were derailed at around 23:00 on Saturday in Andhra Pradesh state."The death toll has gone up to 39," said JP Mishra, a spokesperson for East Coast Railways. He told the NDTV news network there were around 600 people in the derailed carriages.The accident happened two months after 146 people died in a similar disaster in northern Uttar Pradesh state, highlighting the malaise on a network which is one of the world's largest.Anil Kumar Saxena, national railway spokesperson, said investigators were considering the possible sabotage of the tracks by Maoist rebels who he said were active in the area."It is being looked into, it is one of the many angles we are looking into," he told AFP. "There is some suspicion [of sabotage] because two other trains had crossed over smoothly using the same tracks earlier in the night."Police in Odisha, where the train was headed, dismissed any involvement by Maoist rebels known as Naxals in the derailment."We totally reject any possibility of Maoist involvement in the derailment. Kuneru is not a Naxal-hit area," an unidentified senior intelligence officer was quoted as saying by the Press Trust of India. Television footage showed a line of carriages on their sides as rescuers in neon orange safety vests and hard hats tried to hoist passengers through the windows.Workers carried a half-naked passenger, covered in dust, on a stretcher out of a carriage. Another TV image showed a man lying faced down, crushed under mangled heaps of wreckage.Injured victims, their limbs swathed in bandages, lay on hospital beds and stretchers.One passenger, Ranjan Mohanty, described how he was sleeping and was then suddenly flung to the floor of the train."It was horrific and frightening. I was among the lucky ones to have escaped narrowly," Mohanty told PTI. Annual massacreThe train came off the track nearly 160km from Visakhapatnam, the nearest city to the accident site.Railway Minister Suresh Prabhu announced compensation of 200 000 rupees ($2 936) for the relatives of the dead and 50 000 rupees for those injured. India's railway network is still the main form of long-distance travel in the vast country, but it is poorly funded and deadly accidents often occur.On Friday 10 coaches of an express train were derailed in the western state of Rajasthan, leaving many passengers with minor injuries. Last month two people were killed and dozens injured after another train derailed in the north.In 2014 an express train ploughed into a stationary freight train, killing 26.A 2012 government report said almost 15 000 people were killed every year on India's railways and described the loss of life as an annual "massacre".Prime Minister Narendra Modi's government has pledged to invest $137bn over five years to modernise the crumbling railways, making them safer, faster and more efficient."My thoughts are with those who lost their loved ones... the tragedy is saddening," the prime minister said on Twitter.His government has signed numerous deals with private companies to upgrade the network.Japan has agreed to provide $12bn in soft loans to build India's first bullet train, though plans remain in their infancy.