The deadly derailment of a train in Lac-Megantic, Quebec, shows the dangers of transporting oil by rail through highly populated areas. Canadian authorities said they have opened a criminal investigation. (The Canadian Press via Associated Press)

The deadly derailment of a train in Lac-Megantic, Quebec, shows the dangers of transporting oil by rail through highly populated areas. Canadian authorities said they have opened a criminal investigation. (The Canadian Press via Associated Press)