MONTREAL - Canadian National Railway Co. (TSX:CNR) says it has sold a "key section of track" in Toronto to Ontario government-owned Metrolinx for $168 million.

The track, west of Toronto's Union Station, will give Metrolinx ownership of a section of the busiest corridor for its commuter rail service, GO Transit. It also links Union Station to GO's Willowbrook rail equipment facility in southwest Toronto.

CN said it will retain certain operating rights over the line so it can maintain service for its freight customers.

Metrolinx is a Crown corporation responsible for integrating the Greater Toronto Area's transportation network. CN is Canada's largest railway, with operations across Canada and through the American Midwest to the Gulf of Mexico.

Shares in CN lost $1.04 to $61.09 in morning trading on the Toronto Stock Exchange.