Three teenagers were killed while taking selfies on a railway track in India, the country which researchers say has the worst record for selfie-related deaths.A fourth youth managed to jump to safety before the accident in Panipat city in the northern state of Haryana, a police officer told AFP Wednesday."The victims were busy taking selfies and when they saw a train approaching they jumped to a second track without realising another train was coming on that," M. S. Dabas told AFP."One of them saved his life as he jumped on the other side of the track."The group had come to Panipat to attend a wedding. Two of those killed were 19 years old and the third was 18.Experts warn that youngsters obsessed with social media are going to extreme lengths in order to post selfies seen as daring and risky. A study last year by researchers from the All Indian Institute of Medical Sciences said 259 people across the world had died while taking selfies between 2011 and 2017.The highest number of incidents and selfie deaths were reported in India followed by Russia, United States, and Pakistan, the study said.In 2017 three students were killed on a railway track in southern Karnataka state, while a man died in Odisha after an elephant wrapped its trunk around the man and crushed him to death as he tried to take a selfie with the animal.Last year Railways Minister Piyush Goyal took to Twitter to warn people against risking their life for the sake of photographs.