Three individuals and the railway company whose train exploded in Lac-Mégantic, Que., last summer will be charged with criminal negligence on Tuesday, according to the Quebec prosecutor's office.

The provincial prosecutor's office said in a statement that it is filing charges of criminal negligence against three of the company's employees, including Thomas Harding, the engineer who was operating the train before it crashed. Montreal, Maine & Atlantic Railway Ltd. is also facing charges.

The other two employees facing charges are Jean Demaître and Richard Labrie. Mr. Demaître was listed as a manager of train operations for MM&A immediately before the accident, but his name was later removed from the company's website. Mr. Labrie was a company controller, according to a spokesman for the provincial prosecutor's office, who could not confirm whether Mr. Labrie was working the night of the accident.

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René Verret, a spokesman for the Crown's office, said all three men were arrested on Monday afternoon and will appear in court on Tuesday. They are expected in the Lac-Mégantic courthouse around 2 p.m.

Mr. Harding's lawyer, Thomas Walsh, said the provincial police deployed excessive means to arrest his client.

A heavily armed tactical squad showed up with sirens blaring and forced Mr. Harding, his son and a family friend to drop to the ground so they could be handcuffed, the defence lawyer said.

"They're trying to swat a fly with a cannon. It was like an invasion," Mr. Walsh told Radio-Canada Tuesday morning.

He said he had repeatedly told the Crown to issue summons "and Mr. Harding would show up, as he has always done before every time he was questioned [by police]."

Sergeant Aurélie Guindon, a spokeswoman for the Sûreté du Québec, said the force would not comment on Mr. Walsh's remarks.

Mr. Walsh said he did not know if the three men were charged jointly. They may need separate court proceedings because Mr. Harding is anglophone and could request a trial in English while the other two are francophones.

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The devastating accident occurred early on July 6 after a train hauling volatile crude oil broke free from its brakes and careered down a hill into the small town of Lac-Mégantic, causing a massive explosion that destroyed several downtown blocks and killed 47 people.

Mr. Harding had parked the train at the top of a hill in Nantes, Que., and later retired to a hotel room in Lac-Mégantic for the night. After a fire broke out the train's locomotive, local firefighters were called to the scene, where they extinguished the fire and turned off the locomotive.

The Globe and Mail reported in September that a preliminary investigation suggested that the fire was caused by a broken piston. The problem caused unburned fuel to seep throughout the engine, resulting in smoke and sparks on the locomotive.

When firefighters turned off the engine, the air brakes that were holding the train in place gradually stopped working. The Transportation Safety Board said not enough handbrakes had been set on the cars as a backup to the air brakes, and the train rolled down the hill into town, where its crude oil cargo exploded.

MM&A did not have enough insurance to cover the disaster, which will run into the billions of dollars including lawsuits and cleanup costs. The railway filed for bankruptcy protection from its creditors last year and its assets have since been sold to another U.S.-based company.

Edward Burkhardt, who was MM&A's chairman before the company's assets were sold, could not immediately be reached for comment.

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The owner of the Musi-Café, the bar at the centre of the disaster, was at a surprise party with friends when he heard about the charges. Yannick Gagné was to announce the start of work on rebuilding the Musi-Café on Tuesday. The announcement is now in doubt.

"We don't know what's going on any more," he said. "I won't go see them in court, even if there wasn't a conflict, I wouldn't go. It's more important for me to get my life started again."

Raymond Lafontaine, a local businessman, lost family members in the explosion. On Monday night, he was at a city council meeting where he heard that oil trains could start rolling through town again.

"They destroyed half my family. I'll be there in court," he said. "These arrests are justified. These men had a specific job to do. If they had done their jobs well, people wouldn't have died."

Federal Transport Minister Lisa Raitt issued a statement on Monday evening thanking the Quebec police. "I understand that this is difficult for those affected by the tragic incident in Lac Mégantic. As the matter is now before the courts, we have no further comment," she said.

With a report from Tu Thanh Ha

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(Editor's Note: An earlier version of this article incorrectly used the term hydraulic brakes instead of air brakes.)