Jean-Luc Montminy, a volunteer firefighter, headed home in the small hours of July 6, 2013, after helping put out a fire in the lead locomotive of an idling tanker-train at Nantes, Que. 

Waiting at a rail crossing that morning, Montminy saw the same train barrelling toward Lac-Mégantic, where it exploded moments later, killing 47 people. 

Montminy testified Thursday at the trial of three former employees of Montreal, Maine and Atlantic (MMA) railway, at the Sherbrooke courthouse.

​Locomotive engineer Tom Harding, 56, operations manager Jean Demaître, 53, and railway controller Richard Labrie, 59, each face 47 counts of criminal negligence causing death in connection with the tragedy.

Montminy said he'd headed home from Nantes, 12 kilometres northwest of Lac-Mégantic, around 1 a.m. on July 6th, about an hour and a half after extinguishing an engine fire.

As he approached a level railway crossing, he saw its red lights were lit up to warn of an approaching train.

"I stopped my vehicle," Montminy testified. "But then I couldn't figure out what was going on because I didn't hear a whistle or a train engine."

'I couldn't figure out what was going on because I didn't hear a whistle or a train engine.' - Nantes volunteer firefighter Jean Montminy

"I advanced a bit to get a better look. I saw nothing, so I thought there was something wrong with the signal."

Just as he decided to cross the tracks, the train appeared — the motor shut off, all its lights out, moving full speed ahead towards the town of Lac-Mégantic.

"I presumed it was the same train on which we'd just put out the fire," Montminy testified.

"The engine wasn't running, and I recognized the locomotives," he explained.

He said he turned around immediately and, 10 minutes later, was telling his colleagues what he'd just witnessed.

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Train driver Thomas Harding, left, is among three three people charged with criminal negligence in connection with the 2013 Lac Megantic explosion. (Ryan Remiorz/Canadian Press)

"There were still four or five people there," he said. "I told them there was something wrong with the train we'd just worked on, and as far as I could tell, it was headed all by itself towards Lac Megantic."

Just as he was relaying what he'd seen, Montminy said, the fire station got an emergency call.

"They asked us to help with a fire in Lac-Mégantic," he said. "So I got back in my car and headed in that direction."

Told to activate fuel cut-off

Montminy's testimony came on the 21st day of the trial, a day that focused on the fire in the lead locomotive on the eve of the tragedy.

The four firefighters who extinguished that engine fire took turns testifying, describing how they climbed aboard locomotive 5017 and used a mix of foam and water to try to put the fire out.

Firefighter Ghislain Rancourt testified they were told to activate the emergency fuel cut-off.

"Once we did that, the fire died almost right away," Rancourt testified. He said they did not touch any other instruments in the locomotive.

Rancourt told the court that at no time during the operation did anyone let them know the tanker-cars contained dangerous, flammable materials.

He said the volunteer firefighters never received any specific training about putting out fires on trains, either.

The trial before Quebec Superior Court Justice Gaétan Dumas resumes Monday, for a 22nd day.

With files from Claude Rivest and Radio-Canada