Two Lac-Mégantic residents are seeking permission to file a class-action suit against the owners of the train that derailed in their town on July 6.
One of the two men is Yannick Gagne, who owned the Musi-Cafe bar where many people died in the tragedy.
The other is Guy Ouellet, whose partner of five years, Diane Bizier, lost her life in the blaze.
The defendants include the Montreal, Maine & Atlantic railway, company chairman Edward Burkhardt and president Robert Grindrod.
Also cited as a defendant is train operator Tom Harding.
Harding's role is a central question in ongoing investigations into the tragedy; his own company called him a hero one day, then announced the next he had been suspended amid concerns about his role in the disaster.
The court documents were filed in Quebec Superior Court on Monday morning.
No financial sum is mentioned.
Three of Gagne's employees died in the fire.
The action seeks recovery for damages sustained by people who lost loved ones in the explosion and on behalf of people who were injured.
Claims are also being sought for property and business losses.
Lead lawyer Daniel Larochelle, who has lived and practised law in Lac-Mégantic for more than 15 years, knew many of the victims.
"The suffering endured by this community and the suffering that is still ongoing has been truly incomprehensible," he said in a statement.
"I want this legal action to bring some hope to my community as we start to rebuild".
Early in the morning of July 6, a runaway train carrying crude oil jumped the tracks in downtown Lac-Mégantic and exploded into killer balls of flame.
The official death toll is 35 but another 15 people are feared dead.