Crown prosecutors have filed preferred indictments against train driver Tom Harding, railway traffic controller Richard Labrie and Jean Demaitre, the manager of train operations.
The three men as well as Montreal Maine and Atlantic Railway pleaded not guilty to the charges in Lac-Megantic on Monday.
A trial date is to be set on Sept. 8.
All three face 47 charges of criminal negligence causing death — one for each victim of the July 2013 oil-train derailment in the Quebec town. A conviction carries a maximum life sentence.
Harding's lawyer said last month that not having a preliminary hearing would keep the defence in the dark on the Crown's evidence.
Thomas Walsh stressed that stripping Harding of a preliminary hearing would block lawyers on both sides from hearing certain witnesses and deciding which parts of their testimony is credible.
Walsh alleged at the time that prosecutors likely wanted to bypass the preliminary inquiry because they didn't want the weaknesses in their case to show too early.
Preliminary inquiries, Walsh said, save time, while a spokesman for the prosecutor's office said preferred indictments can be requested to serve the public interest by reducing unnecessary delays.
On July 6, 2013, the parked train broke loose, roared downhill toward Lac-Megantic and bounced off the tracks in the middle of town. The explosion set off huge fireballs that wiped out much of the downtown core.