The Montreal-based company, one of North America's largest railway operators, said it's part of CN's efforts to improve the safety of its system.
The Canadian railway sector has come under increased scrutiny this year following a string of high-profile derailments in several provinces.
CN wasn't involved in the worst incident — a deadly disaster last summer that devastated the Quebec community of Lac-Megantic — but its reputation has been tarnished by a number of other mishaps.
The fiery derailment of a CN freight train transporting propane and crude oil in late October forced residents of Gainford, Alta., from their homes for up to four days until firefighters could control the blaze.
Canadian National has argued that its safety record is good despite the recent spate of accidents and adds that the investment in safety announced Thursday will keep it ahead of the industry.
Among other things, CN says it will acquire and install 30 new wayside units that detect hot bearings, hot wheels and dragging equipment.
It will also acquire a new test car to monitor the position, curvature and alignment of track and an optical track inspection system to identify defects. There will also be more equipment to notify train crews of problems.