The Canadian economy is highly dependent on natural resources, and when conditions in the commodity turned sour in 2015, shares of Canadian National Railway (NYSE: CNI) took a major hit. However, over the past year, Canadian National has done a good job of bouncing back from the difficulties it suffered and making the most of the tough environment. Coming into Tuesday’s fourth-quarter financial report, CN investors were hoping for signs of further recovery, and Canadian National’s results showed the progress that the railroad has made.