Up and down railway traffic on main national track came to a halt following a collision between two freight trains near Kotri here Thursday, report said. According to a private TV channel, a freight train was on the track near the Kotri railway station when a Hyderabad-bound freight train coming from Karachi, loaded with oil drums, hit it and a fire broke out. Some 28 goods wagons of the freight train carrying oil were derailed, and oil was spilled. According to the Railway officials, each bogie contains 49,000 litres of oil. Railway authorities have declared emergency after the accident in which two people were also wounded. Rangers have reached the scene and cordoned off the area to avoid any untoward situation, according to reports. Up and down railway traffic on the main track has been suspended following the accident.