SHEIKHUPURA:-Two teenage friends were knocked down by a speeding express train while listening to music through headphones in the ears, near Muridke here on Monday. According to police, Shahzaib,15, and Amanat, 14, were walking across rail track while listening to the music with headphones attached to cellphones. Oblivious to their surroundings, they did not notice the fast-approaching train and crushed to death by the train. The Muridke Saddr Police have started investigation into the incident.