SHERBROOKE, Quebec — The prosecution says the train conductor involved in a 2013 derailment that killed 47 people in Quebec played a significant role in the tragedy because he didn’t apply the brakes sufficiently after parking the oil-laden convoy.

Prosecutor Sacha Blais said in closing remarks Wednesday that Thomas Harding applied only half the required level of brakes and didn’t test them to ensure they worked properly before leaving for the night.

A runaway train carrying crude oil from North Dakota derailed in Lac-Megantic and exploded on July 6, 2013. Harding and former colleagues Richard Labrie and Jean Demaitre are each facing one count of criminal negligence causing the death of 47 people. They have pleaded not guilty.

Closing arguments are expected to last until Friday.