* TSX down 27.2 points, or 0.18 percent, at 15,048.24
* Eight of the TSX's 10 main groups were lower
TORONTO, Nov 28 (Reuters) - Canada's main stock index fell on Monday as railroad, energy and financial names lost ground, offsetting gains for the materials group as base and precious metals prices rose.
At 10:53 a.m. EST (1553 GMT), the Toronto Stock Exchange's S&P/TSX composite index fell 27.2 points, or 0.18 percent, to 15,048.24.
Last week, the index advanced 1.4 percent, extending its rally since the U.S. election.
The most influential movers on the index included railroad stocks, with Canadian National Railway Co falling 0.9 percent to C$89.37, and Canadian Pacific Railway Ltd declining 1.3 percent to C$199.33.
The energy group fell 0.5 percent amid volatility in crude oil ahead of a meeting this week of major oil producers.
U.S. crude prices were up 2.1 percent at $47.03 a barrel, recouping earlier losses as the market reacted to the shaky prospect of the Organization of the Petroleum Exporting Countries being able to agree output cuts at a meeting on Wednesday.
Financials fell 0.3 percent as bond yields declined and investors awaited fourth-quarter results this week from some of Canada's major banks.
Sun Life Financial Inc fell 1.1 percent to C$52.48, while Bank of Nova Scotia was down 0.2 percent at C$72.75.
The recent surge in bond yields had supported the financial sector. Higher bond yields reduce the value of insurance companies' liabilities and increase net interest margins of banks.
Just two of the index's 10 main groups rose.
The materials group, which includes precious and base metals miners and fertilizer companies, added nearly 1 percent, with Barrick Gold Corp gaining 1.2 percent to C$20.25 and Teck Resources Ltd climbing 1.6 percent to C$35.41.
Zinc soared to a nine-year high and lead hit a five-year peak as reports of more infrastructure investment in China and signs of strong property investment in the world's top metals user sparked heavy buying.
Copper prices advanced 1.1 percent to $5,942 a tonne, while gold futures rose 0.9 percent to $1,189.2 an ounce. (Reporting by Fergal Smith; Editing by Bernadette Baum)