Canadian winters bring more than icy roads and chilling winds. They can also create serious economic and operational challenges for freight railways. When temperatures drop below minus 25 degrees Celsius, trains must be reduced in length, weight and speed to run safely. These measures raise costs and reduce service frequency, but they help prevent hazards like uncontrolled train movements. Such incidents happen often enough that they appeared on the Transportation Safety Board's (TSB) 2022 watchlist.
Since 2013, the TSB has investigated 18 similar incidents. One investigation found that extreme cold weather weakened the air brake system, making it unable to stop a moving train. At the time, the TSB could only test freight cars outdoors in natural conditions down to minus 25 degrees Celsius. To address unknowns about performance in Canada's colder northern climate, additional testing was needed.
To fill this gap, researchers from the National Research Council of Canada's (NRC) Automotive and Surface Transportation Research Centre built the Cold Weather Air Brake (CWAB) modular system—a first of its kind system that replicates the braking functions of a train more than 180 metres long inside a controlled climatic chamber. For longer train testing scenarios, multiple CWAB units can be linked. Tested inside the NRC's Climatic testing research facility, the air brakes undergo temperatures ranging from 45 degrees Celsius down to minus 45 degrees Celsius, covering conditions across the North American rail network.
"Our extensive research in this facility quantifies brake system failures in extreme cold weather," says Dr. Elton Toma, NRC Senior Engineer and technical lead for the CWAB project. "Our findings can help Canadian railways adjust operating and maintenance practices to suit their extreme cold operating environments, and Canadian regulators to tailor rules that work for Canada's unique weather challenges."
"While we can't control the weather outside, we can create a controlled environment in the lab down to minus 40 degrees Celsius to understand what is contributing to the mechanical failures at that temperature," adds Toma. "The CWAB has changed the way the industry is able to study air brake functionality in cold weather."
Testing in Canadian conditions
In 2021, Manitoba-based Hudson Bay Railway (HBR) became the first company to work with the NRC in the CWAB facility. Operating year-round in some of Canada's coldest temperatures, HBR sent a dozen freight car air brake systems from in-service freight cars to the NRC for testing. In the lab, the systems were subjected to conditions down to minus 40 degrees Celsius. Controlled brake applications and pressure drop simulations reproduced the situations HBR faces during winter operations.
The tests revealed that systems of 10 to 15 years in service were not as reliable at lower temperatures. They also identified the temperatures at which failures occurred. When these systems were rebuilt, their performance improved dramatically, matching almost-new systems even at minus 40 degrees Celsius. "The research gave us better insights into the operational limitations of our air brake systems in extreme cold," says Brett Young, HBR General Manager.
Thanks to this data, HBR improved travel times by 10 percent, with passenger services becoming more reliable, and doubling weekly freight traffic. Taking what they learned, HBR has made and continues to make positive improvements to their operations and maintenance practices, improving both safety and efficiency.
For the Arctic Gateway Group (AGG), which owns and operates the HBR, the NRC partnership is key. "They give us access to leading research, built upon a wide range of academic and research partnerships that are actively working to help us keep the HBR strong today and into the future," says Young.
Moving down the line
Following the success with HBR, the NRC continued the cold weather air brake testing with Transport Canada. That work is now complete, with final reports in progress, setting the stage for future collaborations with other Canadian railways.
With the CWAB system, NRC is helping Canada's rail sector adapt to its harshest climates — improving safety, efficiency, and resilience across the country's vast northern network.