Sagnik Basu The Kalka Mail pulled out of Howrah Station at exactly 7:40 p.m., its long, rattling compartments groaning like a creature awakened from slumber. Among the many passengers boarding that evening was Anant Vashisht, a man in his late sixties, lean and upright, with a faded Nehru jacket and an expression that gave nothing away. He moved quietly through the First AC coach, berth 42, settling into his compartment with the calm precision of someone trained to disappear in plain sight. He carried one thing of interest—a brown leather briefcase with steel corners, chained to his wrist. Fellow passengers…