Environment and Forests Jairam Ramesh will hold discussions with the Railway Ministry to protect the key elephant corridors. Expressing his deep concern over the killing of seven elephants in West Bengal by a running Goods Train on Thursday he said such incidents have not taken place for the first time. But the scale of killing the animals this time has been unprecedented.Speeding trains have mowed down 150 elephants since 1987. The death of seven elephants yesterday has brought to fore the threat the jumbos are facing in the country. According to the latest report of the Elephant Task Force of the Environment Ministry, West Bengal comes second after Assam in elephant casualties due to train movements. Most of the accidents have happened in summer between January and June by night-bound trains when the animals venture out in search of water and food.