(Updates prices, adds sectors) April 20 (Reuters) - Canada’s main stock index slipped on Tuesday, pressured by industrial shares as Canadian National tumbled after it offered to buy railroad operator Kansas City Southern for $30 billion. * Canadian National’s shares dropped 7.5% and was the worst performer on the main index after the company trumped a rival bid by Canadian Pacific to buy Kansas City Southern. * That led to the industrial sector posting a decline of 2%. * At 9:44 a.m. ET (13:44 GMT), the Toronto Stock Exchange’s S&P/TSX composite index was down 117.6 points, or 0.61%, at 19,086.82. * The energy sector dropped 2% even as U.S. crude prices were up 0.3% a barrel and Brent crude added 0.5%. * The materials sector, which includes precious and base metals miners, lost 0.2% as gold futures fell 0.1% to $1,767.9 an ounce. * On the TSX, 76 issues were higher, while 150 issues declined for a 1.97-to-1 ratio to the downside, with 15.29 million shares traded. * The largest percentage gainers on the TSX were Spin Master Corp, which jumped 2.7%, and Altus Group, which rose 2.1%. * The most heavily traded shares by volume were Zenabis Global Inc, Bombardier and Air Canada . * The TSX posted five new 52-week highs and one new low. * Across all Canadian issues there were 26 new 52-week highs and nine new lows, with total volume of 33.50 million shares.