At least four people were killed and dozens were injured in the head-on collision between a passenger train and a freight train in the central Czech city of Pardubice, emergency services said, reports iDNES news portal. Some of the injured are in critical condition. Search and rescue operations continue at the scene, 36 units and two helicopters are involved. The passenger train belonging to the commercial company Regio Jet was traveling from the Czech capital Prague to the city of Kosice in eastern Slovakia. It was carrying more than 300 passengers. In the collision, which occurred at 10:53pm local time, its first carriage, carrying about 20 passengers, suffered the most damage.