Some industry observers have said oil trains are more prone to derailments because they often exceed 100 cars and push the load-bearing capacity of tracks and wheels. Zarembski disagrees. "We call them 'unit trains,' and they are big, long, heavy trains and have been used by railroads to move the world's major commodities for decades. There is nothing new in the axle loads of oil trains," he says. "The railroads are good at moving long, heavy trains."

In 2015, freight railroads expect to spend $80 million per day on enhancing rail infrastructure and equipment, says Ed Greenberg, American Association of Railroads. "Since 1980, America's rail-freight industry has injected more than $575 billion into maintaining and modernizing the nation's freight rail network."

The Canadian Railway Association had a similar response to ENR's inquiry regarding its efforts to curb oil train derailments. "Canada's railway industry has invested more than $13 billion since 2002 to ensure the safety of its infrastructure—including investments in innovative safety technologies," said CRA's Alex Patton in an email to ENR.

CN and BNSF did not respond to ENR's request for comment.