In legal documents filed late Thursday, lawyers involved in the class-action suits allege CP Rail bears some of the responsibility for the deadly derailment.
Jeff Orenstein, one of the lawyers representing survivors of the disaster, said CP Rail turned a blind eye to the shortcomings of the Montreal, Maine and Atlantic Railway when it subcontracted the transportation of highly explosive material to the smaller carrier.
"They were also aware, or should have been aware, of MM&A's poor safety record, as well as their inadequate insurance coverage," Orenstein said.
The court documents state that CP Rail permitted a dangerous situation to exist, and with reasonable effort it could have prevented or limited the scope of the deadly derailment.
By adding CP Rail to the list of potential targets, class action lawyers are seeking to increase the amount of a potential settlement, for while MM&A is bankrupt and underinsured, CP Rail has deep pockets.
CP Rail has declined to comment on the latest salvo against it.
CP Rail rejects Quebec government order
On Thursday, the railway said it has no financial duty for the Lac-Megantic rail disaster, rejecting a Quebec government demand that it help pay for the cleanup.
On Wednesday, Quebec added CP Rail to a list of defendants that it says are financially responsible for a cleanup estimated at $200 million, according to bankruptcy documents filed by MM&A earlier this month.
Environment Minister Yves-François Blanchet reacted quickly, saying a minister does not ask for, or suggest, compensation, "he orders it."
"I'm not surprised," Blanchet said of CP Rail's response, in an interview on Radio-Canada on Friday. "I'm disappointed. But it was expected."
"I said from the start, did all those companies involved, all those responsible, step forward to say, 'We're going to fix this. We're going to make sure things are cleaned up?'"
Blanchet said CP Rail's dismissal of the province's demand is a "bad public relations move."
"Citizens are going to judge these companies," he said.