Tanker cars under scrutiny after spilling oil in recent derailments

New questions are being raised about the safety of CPC-1232 rail tanker cars currently in use on Canadian railways after they were involved in two accidents in the past week that involved oil spills and fire.

The CPC-1232 tankers are the stronger cars the rail industry agreed to use for transporting oil and chemicals, after the older DOT-111 cars were involved in the fiery Lac-Mgantic, Que., disaster.

But on Saturday, 29 cars of a 100-car Canadian National Railway train carrying diluted bitumen crude derailed in a remote area of Ontarionear Gogama, south of Timmins. Oil was spilled amid the snow and caught fire, burning for two days.

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The Transportation Safety Board said it would investigate the role of CPC-1232 tanker cars in that accident, though other factors such as track condition are also under review.

Then on Sunday, a train carrying crude derailed in West Virginia, sending a fireball into the sky and leaking oil into a tributary of the Kanawha River.The fire burned for three days and a house nearby was destroyed.

Those tankers were also the CPC-1232 model and had carried oil from the Bakken shale, which has a reputation for being extremely volatile.

New safety standards

Canadian railways committed to ending use the old DOT-111 tankers after an investigation into the Lac-Mgantic fire and explosion that killed 47 people. They replaced the old tankers withCPC-1232 tankers.

Transport Canada also recommended a series of upgrades to safety practices in the wake of the accident.

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Transport Canada began consultations on a new class of evenstronger tankers for flammable liquids last July and continues to consult with U.S. regulators, a spokeswoman told CBC. It has suggestedmoving to ajacketed, thermally insulated tank car with a full head shield, top fitting protection and a new bottom outlet valve, a much more expensive alternative for the oil industry or rail companies.

The U.S. has been drafting its own safety upgrades in response to accidents involving oil shipment as the amount of crude moved by rail has increased from 9,500 carloads in 2008 to more than 435,000 in 2013.

The CPC-1232 tankers are made of thicker steel than the old tankers, with improved valve technology and a thick shield on the front and back of the car to protect the car from being punctured by a rock or branch.

The U.S. administration has pondered settingthe standards still higher, with an even stronger tanker car.

Can any tanker withstand high-speed derailment?

But transportation consultant Harry Gow says it would be difficult to make a tanker that could withstand an impact at more than 100 km/h the speed the train that hit Lac-Mgantic was travelling.

"There comes a point beyond which no tanker can withstand impact stresses in a derailment,"he told CBC News.

Gow, president of advocacy group Transport 2000 Canada, said new standards for tankers may help, but the better tankers may be able to withstand an impact of just 29 km/h, rather than a derailment at high speed.

"There is a degree of assurance that these tankers can withstand a derailment in a rail yard, for example, when theyve gone over a switch, but there is nothing that withstands a fall of three stories into a river,"he said, referring to the accident in West Virginia.

The National Transportation Safety Board in the U.S. is investigating the West Virginia accident and plans to look at the performance of the CPC-1232 tankers in that derailment and another near Casselton, N.D., that resulted in a fireball and explosion.