(New throughout, updates prices, market activity and index levels)
* TSX down 36.99 points, or 0.23 percent, to 15,868.15
* Six of the TSX's 10 main groups retreated
TORONTO, Oct 25 (Reuters) - Canada's main stock index fell on Wednesday with Canadian National Railway Co leading the retreat after results missed forecasts.
Canada's largest rail operator gave up all of the previous session's pre-earnings gains and fell 1.9 percent to C$103.46, after several analysts also cut their price targets on the company. Industrials fell 0.6 percent.
Roots Corp, tumbled 15.8 percent to C$10.10 in its trading debut in Toronto after raising C$200 million in an initial public offering.
At 10:46 a.m. ET (1446 GMT), the Toronto Stock Exchange's S&P/TSX composite index fell 36.99 points, or 0.23 percent, to 15,868.15.
Of the index's 10 main groups, six sectors lost ground.
TransCanada Corp was one of the most influential decliners after CN Rail, falling 1.4 percent to C$60.06. The company said earlier on Wednesday it was selling its Ontario solar assets for C$540 million.
The overall energy group, however, was little changed, with oil prices steady after data showed a surprise build in U.S. crude inventories.
Another industrial stock, Air Canada, was down 0.8 percent to C$26.14 after opening higher following quarterly results that were better than expected.
The heavily-weighted financial services sector slipped 0.2 percent with Fairfax Financial Holdings Ltd sliding 1.3 percent to C$646.56.
The materials group, which includes precious and base metals miners and fertilizer producers, lost 0.3 percent.
Tempering some of the losses included Telus Corp, which rose 2.5 percent to C$46.85. The broader telecoms group gained 0.8 percent.
On the economic front, the Bank of Canada held interest rates steady, as expected, but expressed caution as it considers future moves given the risks and uncertainties facing the economy.
Declining issues outnumbered advancing ones on the TSX by 153 to 84, for a 1.82-to-1 ratio on the downside.
The index was posting 12 stocks hitting new 52-week highs and four issues touching new lows. (Reporting by Solarina Ho; Editing by David Gregorio)