NEW YORK, May 15 (Reuters) - * The Toronto Stock Exchange's S&P/TSX rose 12.20 points, or 0.08 percent, to 16,097.81. * The biggest contributor to the TSX gain was Canadian National Railway Co, with 10.1 net index points. Industrials were the top sector contributor with 13 net points. * Leading the index were Element Fleet Management Corp, up 12.1 percent, Aphria Inc, up 7.5 percent, and Boyd Group Income Fund, higher by 4.8 percent. * Lagging shares were Semafo Inc, down 4.6 percent, Yamana Gol