Railway officials in Congo Brazzaville say about 50 people have been killed and many more injured in a train crash in the south of the country. Officials say the train plunged off the rails after taking a curve too fast. Four of the train's carriages plunged into a revine near a station about 60 kilometres from the coastal city Pointe Noire. The 510-kilometre rail line is the main link between the capital Brazzaville and Pointe Noire on the Atlantic.