The lawyer for the traffic controller the night of the Lac-Megantic derailment says his client had no need to check with the conductor whether he had adequately secured the train before leaving for the night.

In his closing arguments Friday, Guy Poupart said Richard Labrie had a limited role in the tragedy in which 47 people were killed when a runaway train carrying crude oil derailed and exploded in Lac-Megantic in the wee hours of July 6, 2013.

Labrie, train conductor Tom Harding and Jean Demaitre, the manager of train operations -- who were all employees of Montreal Maine and Atlantic Railway -- have pleaded not guilty to a charge of criminal negligence causing the death of 47 people.

The Crown has argued the tragedy could have been avoided if Labrie and Demaitre had asked pertinent questions about whether the train had been secured the night before the derailment.

The prosecution has said neither man deemed it necessary to check with Harding to see how many handbrakes had been applied and whether tests had been conducted -- even though firefighters had extinguished a blaze at the lead locomotive shortly before the tragedy.

The firefighters also cut the engine, which meant the air brakes were not functioning.

Poupart used his closing remarks to refer to the testimony of several people who described Labrie as competent and reliable and someone they trusted.

And that mutual trust, Poupart argued, is the reason Labrie did not have to ask Harding whether the brakes had been properly secured.

Harding had stopped the train on top of a slope in nearby Nantes before it began moving on its own, barrelling into Lac-Megantic.

As Quebec provincial police had informed Labrie of the earlier fire, the Crown has argued he should have checked with Harding about the brakes.

Poupart said while it is true his client did not do that, he added, "it is true he didn't have to do it."

"Richard Labrie was entitled to expect the train to be immobilized according to requirements, regardless of whether the engine was on," Poupart told the 14 jurors.

He also told them Labrie had a limited role in the tragedy as he was actually 200 kilometres from Lac-Megantic when the train derailed.

Labrie, he continued, could not know about possible mechanical issues with the lead locomotive if he was kept in the dark.

"He isn't able to foresee things if he's not told about them," Poupart said.

The lawyer added that a good portion of the Crown's evidence did not concern Labrie and he asked they take that into account when they begin their deliberations.

The Crown argued in its closing arguments Wednesday that Harding applied only half the required level of brakes and didn't test them to ensure they were working properly before he left for the night.

Demaitre's lawyer had his turn Thursday and Harding's attorney is expected to address the court on Monday before Quebec Superior Court Justice Gaetan Dumas gives his instructions to the jury.