While the jury was out of earshot, the Quebec Superior Court judge presiding over the trial of three men indicted for their roles in the Lac-Mégantic rail disaster acknowledged the Crown's case against two of the accused was not persuasive.

"I'm aware the evidence is weak," Justice Gaétan Dumas told the court in the absence of the jury on Dec. 11. "However, it's not up to me to evaluate it. That's the jury's job."

Dumas made the comments after rejecting a defence motion to acquit two of the men, former Montreal, Maine and Atlantic (MMA) railway traffic controller Richard Labrie, 59, and ex-MMA operations manager Jean Demaître, 53. Along with former locomotive engineer Tom Harding, 56, they are each charged with criminal negligence causing the deaths of 47 people.

Now that the jury in the marathon trial is sequestered and has begun its deliberations, CBC News is free to report on arguments and motions that had been subject to a publication ban.

Former Montreal Maine and Atlantic Railway Ltd. employees Tom Harding, right, Jean Demaître, centre, and Richard Labrie are escorted by police to appear in court in Lac-Mégantic in 2014. (Ryan Remiorz/Canadian Press)

Throughout the three-month trial, the Crown attempted to demonstrate that, as Harding's supervisors the night of the disaster, Labrie and Demaître hadn't done their jobs.

"Their failure to take the appropriate measures to prevent the train from moving was a key cause of the derailment," prosecutor Véronique Beauchamp argued.

After hearing from the Crown's 31 witnesses over more than two months, however, lawyers for Labrie and Demaître argued the Crown hadn't met the burden of proof of the case against their clients.

Demaître's lawyer, Gaétan Bourassa, said there was no rule in effect in July 2013 that required locomotive engineers to inform their supervisors that a train had been properly secured.

As a result, Bourassa told the judge, his client had no reason to wonder if Harding had engaged a sufficient number of handbrakes when he left the 73-car fuel train idling at Nantes, Que., 13 kilometres from downtown Lac-Mégantic.

Labrie was the rail traffic controller at MMA on the night of the derailment and explosions. His lawyer argued the Crown never proved he was negligent in his duties. (Ryan Remiorz/Canadian Press)

Labrie's lawyer, Guy Poupart, argued in the case of his client, not a single Crown witness testified that the railway traffic controller was supposed to have been informed by a locomotive engineer "that he was now ready to leave the site where the train was secured."

Dumas ultimately rejected the defence motion for a directed verdict to acquit the two men.

"It's not up to the judge to examine the quality of the evidence," he said, citing legal precedents.

"It's the jury's job to determine if Demaître and Labrie ... took steps to avoid bodily harm to other people."

'Like pulling teeth'

Dumas, who is known for his direct manner and sometimes colourful speech, made no secret of his frustration with legal counsel, especially with the Crown, when the jury was not present.

He said at times, getting answers to key questions from the prosecution was "like pulling teeth."

It's not up to the jury to play wizard. — Justice Gaétan Dumas

"Four Crown prosecutors have worked full time on this case for three years," he said at one point. "That's the equivalent of 12 lawyer-years. I can tell you had I had 12 years on one file, I would have been able to respond to questions about it."

Dumas cited the example of the fire in the smokestack of the lead locomotive, put out by local firefighters called to the train, which had been left idling in Nantes two hours before the derailment.

No Crown witness could explain what caused the fire.

"It's not up to the jury to play wizard," Dumas said.

'I'm aware the evidence is weak,' Superior Court Justice Gaétan Dumas told the court in the absence of the jury on Dec. 11. 'However, it's not up to me to evaluate it. That's the jury's job.' (Radio-Canada)

The Crown had also reproached Demaître for not doing anything when he learned there was a mechanical problem with the lead locomotive a few hours before Harding drove the convoy to Nantes on July 5, 2013.

"If you're trying to suggest [to the jury] that changing the locomotive would have prevented the accident … that's not what caused the accident," Dumas chided the prosecution.

He continued, sarcastically, "Mr. Demaître's mother isn't charged! If she hadn't brought him into the world, this wouldn't have happened."

TSB report ruled inadmissible

The trial of the ex-MMA employees began more than two years after the federal Transportation Safety Board issued its report on the Lac-Mégantic tragedy, concluding, "no one individual, a single action or a single factor" caused the derailment.

The TSB report left no doubt about problems with the MMA railway company, however.

"The TSB found MMA was a company with a weak safety culture that did not have a functioning safety management system to manage risks," the agency said.

The TSB report identified 18 causes of and factors contributing to the accident, including gaps in training, employee monitoring and maintenance practices at MMA, a failure by Transport Canada to audit the railway often or thoroughly enough, and the fact that the rail line between Nantes and Lac-Mégantic is the steepest slope in Quebec — and the second-steepest in Canada.

Even before the TSB report was issued, the agency made urgent recommendations to revise the way crude oil and other highly volatile materials are carried by rail.

The jury will not consider any of the TSB's conclusions in its deliberations, however. Before the trial began, Dumas deemed the report inadmissible.

Judge has faith in jury's smarts

That played into other arguments from which the jury was excluded.

One of the Crown's key witnesses was a railway expert, Stephen Callaghan, who had been hired by the Quebec provincial police to help in its investigation.

Before Callaghan testified, the Crown argued his report on the disaster should not be entered as evidence, because it referred to the inadmissible TSB report.

Dumas rejected the Crown's argument.

"This is like saying the jury isn't intelligent, so we won't give them the expertise," he said.

Safety of one-man crews

MMA had instituted one-man crews on the run through Lac-Mégantic just months before the disaster.

The jury heard expert evidence that the only other railway in Quebec with a one-man crew operation, Quebec, North Shore & Labrador (QNSL) railway, had to respect 69 conditions imposed by Transport Canada before it could adopt them, while MMA had to comply with a single condition — the addition of a rearview mirror to the driver's side of the lead locomotive.

The jury also heard that MMA employees did not like the single-person crews, and Harding's lawyer, Thomas Walsh, wanted to analyze their safety.

"One-man crews aren't safe," Walsh argued, in the absence of the jury, pointing out the day after the derailment, they were discontinued.

"Somebody caught on. We should be able to present evidence of that."

Dumas rejected that argument.

"We are not here to try the rules," he concluded.