Canadian National Railway CEO Claude Mongeau told a business group Tuesday that tanker design was one of the "most important systematic issues" associated with the accident.
"That question is central," he told the Montreal Board of Trade, adding that railway industry associations in Canada and the United States have recommended the gradual replacement of old cars with new, reinforced tankers.
But he said there is no easy solution because the tankers are mostly owned by railway customers and leasing companies.
"It will take money and time to make sustainable changes in this area."
Mongeau said CN is committed to safety and does far more than what is required by regulatory standards. He described the company's safety record as "solid" and continuously improving. The number of accidents have been cut in half over the last decade because of significant investments in infrastructure maintenance and detection technologies.
While the risk of accidents can't be eliminated, he said 99.997 per cent of CN shipments arrive without incident at their destination. And last month's incident in Gainford, Alta., demonstrated the railway's ability to respond quickly when problems do arise, he said.
There have been four train derailments in Alberta in the past two months, including one in October that sparked a dangerous petroleum fire that forced the evacuation of the village of Gainford.
CN dispatched its top brass, led by chief operating officer Jim Vena, to handle the crisis after 13 cars carrying crude oil and liquefied petroleum gas came off the tracks and caught fire west of Edmonton.
"You can rest assured that we are taking account of Lac-Megantic and carefully reassessing risks in context,' he said, adding that CN has reviewed its train securement practices in line with the Transport Canada directive earlier this summer.
It also extended the U.S. policy to moving dangerous goods to all flammable products moved in both countries.
CN (TSX:CNR) is also increasing detection capability by adding track testing equipment to detect problems before they arise, even though inspections have increased by 70 per cent in the last five years.
A rail safety audit completed just days before the deadly July train crash found "significant weaknesses" in Transport Canada's oversight of federally regulated railways.
Those weaknesses include a lack of knowledge of rail routes used to transport dangerous goods, too few safety auditors, poorly trained inspectors and an absence of follow-up or sanctions when safety problems are found.
Auditor-General Michael Ferguson found that only 14 safety audits of Canada's 31 federally regulated railways had been completed in the previous three years — just a quarter of the audits Transport Canada had expected to carry out.
And eight of those 14 audits focused on just the two largest operators, CN and Canadian Pacific, leaving Canada's smaller operators largely unchecked.
One of those small rail companies was the Montreal, Maine and Atlantic, whose unattended, single-operator train carrying 7.6 million litres of volatile crude oil derailed and exploded in the middle of Lac-Megantic on July 6, killing 47 people.