Canadian National Railway said it had a profit of $775 million in the first quarter, 16 percent more than the $668 million in the first quarter of 2011. Revenue in the first quarter was $2.35 billion, up 13 percent from $2.08 billion in the same 2011 period. Claude Mongeau, president and chief executive officer, said the company benefited from a milder winter and improving economic conditions, but that “CN’s commitment to operational and servi...