Canadian National Railway has said that it is planning to retire a fleet of its 183 older DOT-111 tank rail cars in a phased manner during the coming four years as part of its plans to improve safety on its network.

Canadian National Railway will spend $7 million within this year to replace the 40 DOT-111 tank cars that are used to carry diesel fuel to its freight yards. The remaining 143 leased DOT-111 cars will be phased out as their leases conclude during the coming four years. The older cars used to carry flammable liquids have caused concerns among the regulators for safety issue.

A spokesman of Canadian National Railway said that, "Older DOT-111 tank cars comply with current regulatory requirements, so CN, under its common carrier obligations, is obliged to transport them." The company is planning to replace them with cars meeting the newest regulatory standards. The new cars will have thicker hulls and is less likely to derail. The company said that it is responsible for tankers it owns or leases itself and will work to enhance security.

"The question of tank car robustness is central, and that question is being addressed by the American Association of Railways, to which CN belongs, in recent recommendations calling for the retrofitting or phase-out of the old DOT-111 cars used to transport flammable liquids and a reinforced standard for new tank cars built in the future," Mongeau said in his statement Tuesday.