Newly released audio casts a new light on the Lac-Megantic rail disaster, revealing the urgent exchange between a railway engineer and his company dispatcher as tragedy unfolded in the small Quebec town.

The audio captures a series of phone conversations between Tom Harding and the MM&A company dispatcher, identified as RJ, on July 5 and 6, 2013.

Two hours after Harding had parked the ill-fated train for the night, he called his company's communications centre to inform them about the fire that had been raging in downtown Lac-Megantic for 30 minutes. At that point, neither RJ or Harding knew why.

“Listen emergency. The town of Megantic is on fire. Do we have tankers in the yard anywhere?” Harding says.

“Everything is on fire, from the church all the way down to the Metro, from the river all the way to the railway tracks,” Harding says. “The yard is gone. The flames, RJ, are 200 feet high. It’s incredible, you can’t believe it here.”

Another 42 minutes pass, and at 3:29 a.m., as a fireball in downtown Lac-Megantic rages, Harding hears for the first time that his train caused the fire.

“It’s worse than that,” RJ says to Harding. “It’s your train that rolled down.”

“No,” Harding said.

Harding has been charged with 47 counts of criminal negligence causing death.

Released earlier this week, a Transportation Safety Board report into the disaster determined that Harding didn’t apply the correct hand brakes to secure the train.