GUWAHATI, India (Reuters) - It is an unexpected headache for the Indian army, an unlikely embarrassment for the government and an unwelcome challenge for the railways department. Elephants in India are on the rampage, coming into conflict with man ever more frequently and ever more dangerously. It is a battle the normally gentle animals seem destined to lose. In the northeastern Indian state of Assam, elephants have been raiding army depots, eating the military's rations, drinking its liquor and leaving a trail of destruction in their wake. In Bangladesh, stray elephants from India have been terrorizing villagers and destroying farms,...