Rail transportation safety investigation R23E0079

The occurrence

On 08 August 2023, Canadian National Railway Company (CN) train Z11531-06 (train 115) was travelling westward on the Wainwright Subdivision when it collided with the side of CN train S77181-04 (train 771), travelling in the same direction, near Wainwright, Alberta. The 2 head-end locomotives on train 115 derailed, as well as the 2 intermodal cars immediately behind the locomotives; on train 771, 6 cars loaded with sand derailed. 

The investigation found that train 115 went past a Stop signal at Mile 141.7 and collided with train 771 at Mile 141.9 as that train was departing Wainwright Yard. 

Train 115 was operated by a conductor locomotive operator (CLO) trainee, who was being trained by a locomotive engineer (LE). The investigation found that the LE experienced a significant decline in cognitive functions that negatively affected his ability to coach the trainee at a critical moment. The trainee had to make independent train handling decisions beyond his competency level and did not apply sufficient braking to stop the train before the Stop signal.

The signs of progressive decline in cognitive functions exhibited by the LE are consistent with many of the physiological symptoms of hypoglycemia (restlessness, drowsiness, difficulty concentrating, and confusion). As no post-occurrence blood glucose testing or medical assessment was conducted, the investigation could not determine with certainty the reason for the observed decline in the LE’s cognitive functions.

Hypoglycemia is a common occurrence in people with insulin-treated type 1 diabetes. The LE involved in this occurrence was insulin-treated for type 1 diabetes. 

This occurrence highlights the risks associated with railway employees with medical conditions, such as diabetes, who may experience sudden impairment or impairment of cognitive functions while performing safety-critical operations.

The investigation also found that a breakdown in communication and shared situational awareness among the crew members of train 115 also contributed to the delay in making a decision to stop the train. 

Safety action taken

After this occurrence, CN added a special instruction that requires freight trains to reduce their speed to 10 mph below the permissible track speed before passing a Clear to Stop signal indication. Following that, CN issued a bulletin to remind employees that, when operating in a critical focus zone, only conversations involving immediate train operations must be discussed. The bulletin also reminded junior employees to call signals when they positively identify them and to not be shy about speaking up. 

Safety concern

Transport Canada (TC) requires railway companies to comply with the Railway Medical Rules for Positions Critical to Safe Railway Operations (Railway Medical Rules) to ensure that personnel in safety-critical positions who have a medical condition are medically fit for duty.

According to the Canadian Railway Medical Rules Handbook,To help Canadian railways understand and apply the provisions under the Railway Medical Rules for Positions Critical to Safe Railway Operations, the Railway Association of Canada developed the Canadian Railway Medical Rules Handbook, which CN applies as its policy in accordance with the rules. a person’s type 1 diabetes is considered medically stable when, among other conditions, they have not had an A1CA1C is the measurement of average blood glucose control for the last 2 to 3 months; approximately 50% of the value comes from the last 30 days. level greater than 12% within the previous 3 months.

That level is higher than the A1C level recommended by Diabetes Canada, which recommends that A1C be 7.0% or less and not higher than 8.5% to reduce the risk of symptomatic hyperglycemia and complications.

Over previous years, the LE consistently had A1C levels higher than the level recommended by Diabetes Canada, but below the level indicated in the Canadian Railway Medical Rules Handbook. 

In contrast, the guidelines pertaining to medical fitness for duty for insulin-treated employees in the air industry require that pilots maintain A1C levels in line with Diabetes Canada’s target. Restrictions can also be placed on pilots’ licences depending on their risk level. In the marine industry, insulin-treated seafarers are restricted to limited, contiguous waters voyages, as international standards disqualify them from unlimited voyages due to the risk of hypoglycemic events. 

As a result, the Board is issuing the following safety concern:

Safety action required

In the air and marine transportation sectors, TC is responsible for certifying the medical fitness for duty of operational personnel in safety-critical positions. In the rail transportation sector, this responsibility is within the purview of railway companies.

The Railway Medical Rules require that employees be assessed for medical fitness for duty, taking into consideration medical conditions that could result in impairment, including sudden impairment and impairment of cognitive functions. 

The investigation determined that, in the LE’s medical file provided by CN, there were no annual diabetes assessments for the years 2011, 2012, 2013, 2017, 2020, 2022, and 2023. Assessments for some other years were incomplete. CN accepted the incomplete assessments, thereby not having all the relevant information to determine if the LE’s diabetes was medically stable.

Without all the required information, railways may not have accurate knowledge of employees’ medical condition, leading to a risk that medical issues could go undetected, potentially allowing employees to continue working while medically unfit, thereby increasing the risk of accidents.

In the 12 years preceding the occurrence, TC did not conduct audits to verify CN’s compliance with the Railway Medical Rules. As a result, the gaps in the LE’s medical assessments were not captured through regulatory oversight.

Therefore, the Board recommends that