On the evening of October 7th, approximately 40 students were travelling by school bus to a dance, when the bus reached a level crossing. The gates lowered, preventing the school bus from crossing and allowing an eastbound train to continue its route. After the train had passed, the gates rose, allowing the school bus to cross. As the bus began to drive over the level crossing, a second train heading west, without warning, struck the bus and split it in half, dragging one half with it for over 2000 feet (600 m). The other half of the bus was found in a ditch approximately 300 feet (91 m) from the crossing. Of the 41 people on board, 19 were killed instantly, including the bus driver. Funerals for the deceased took place on October 11, 1966 at the Cité-des-Jeunes high school, where the students had gone to school.
Since the accident, there has been much speculation as to why and how it occurred. Numerous hypotheses include malfunctioning crossing gates and that a number of students were seen lifting the gate to allow the bus to continue its path. After years of investigation, the coroner released a statement declaring accidental death with no criminal ties, and the investigation was closed shortly thereafter, citing that the crossing gates were in no way defective and that eyewitness testimony proved that two or more students lifted the gates despite the possibility of another oncoming train.
After receiving numerous complaints, requests to reopen the investigation and public demonstrations of disagreement by the citizens of the city of Dorion, the level crossing was replaced by a double underpass under the direction of Paul Gérin-Lajoie in November, 1972.
On October 7, 2006, Francine Tougas unveiled her documentary entitled "Survivre" at the Cité-des-Jeunes high school, which documents the reaction to the Dorion level crossing accident by the government, CN Rail, citizens of the city of Dorion, the families of the 19 students killed and the families of the surviving students.