* TSX rises 27.51 points, or 0.20 percent, to 13,485.57 * Six of the 10 main index sectors advance * Bombardier climbs 1.5 percent after signing CSeries deal By John Tilak TORONTO, Nov 19 (Reuters) - Canada's main stock index climbed to a moderate gain on Tuesday, boosted by its energy and materials sectors as investors brushed aside concerns that the recent rally might have been overdone. The Toronto stock market's benchmark index, which is up more than 8 percent this year, hit a two-year high in the previous session. With market focus glued on U.S. Federal Reserve monetary policy and China's plans for social and economic reform, some investors have started to question whether the gains made by global stock markets are sustainable. Billionaire Carl Icahn said on Monday he is "very cautious" on the stock market, saying he could see a "big drop" because earnings at many companies are fueled more by low borrowing costs than by the strength of management. "The reality is we've had a very strong month or so of very good returns," said John Stephenson, senior vice president at First Asset Investment Management, who said he sees little cause for concern about the Canadian market. The earnings beat on the TSX in the most recent quarter has been much cleaner than the beat on the S&P 500, he said. The Toronto Stock Exchange's S&P/TSX composite index was up 27.51 points, or 0.20 percent, at 13,485.57. The benchmark Canadian index is up about 5.3 percent in the quarter to date. Stephenson said Canada will benefit from strong global demand: "As a smaller market that's geared to global growth as opposed to domestic growth, the TSX should do very well next year." Six of the 10 main sectors on the index were higher on Tuesday. A gain in the price of U.S. crude oil helped push shares of energy companies up 0.6 percent. Canadian Natural Resources Ltd climbed 0.7 percent to C$33.87, and Encana Corp jumped 1.9 percent to C$19.90. The materials sector, which includes mining stocks, gained 0.4 percent. Goldcorp Inc was up 1.1 percent at C$25.47, and Barrick Gold Corp rose 0.7 percent to C$18.55. Financials advanced 0.2 percent, with Manulife Financial Corp adding 1.4 percent and having the biggest positive influence on the market. In company news, Bombardier Inc said it signed a letter of intent to sell five CSeries jetliners to Iraqi Airways. Bombardier shares gained 1.5 percent to C$4.72.