Locomotive engineer’s mental model to blame for train passing a Stop signal indication

Operator has 12 similar occurrences in total

Locomotive engineer’s mental model to blame for train passing a Stop signal indication

The locomotive engineer’s (LE) “mental model” is to blame for an incident when they did not stop even though a Stop signal indication was displaying at Mai Station in Quebec, according to the Transportation Safety Board of Canada (TSB).

The incident happened on Feb. 22, 2023. An ore freight train operated by Quebec North Shore and Labrador Railway (QNS&L) was proceeding on the Wacouna Subdivision heading for a crew change at Mai Station, Quebec.

As the train was pulling towards the station camp, it passed a signal displaying a Stop indication.

The signal was visible 0.75 miles away, but the LE did not conduct the braking manoeuvres required to stop before the signal. 

The LE applied full dynamic braking and the emergency brakes when they were already 50 feet past the signal

Thankfully, the incident did not result in a collision, derailment or injuries, said TSB.

“The investigation determined that the LE’s mental model was likely affected due to routinely stopping the lead locomotive of his train in front of the camp located after the signal,” said TSB. “Furthermore, the LE had developed a habit of not always broadcasting Stop signal indications on the railway radio as required by the Canadian Rail Operating Rules.” 

TSB also found that there have been 12 occurrences in total of QNS&L trains passing Stop signals in the last 10 years.

“Human performance and experience were considered as factors in all these occurrences,” said TSB.

“Following railway signal indications is a TSB Watchlist issue. As this occurrence demonstrates, railway signals are not consistently recognized and followed, which in the absence of physical fail-safe defences, poses a risk of train collisions or derailments that can have catastrophic consequences.”

On Sept. 7, 2023, the TSB sent a safety information letter to QNS&L on the supervision of newly qualified LEs. In response, the train operator made changes to its evaluation program for apprentice LEs and increased the frequency of evaluations by supervisors in the field for LEs with less than two years of experience.