TTC OPERATED BY ENSCO, RAILWAY AGE FEBRUARY 2025 ISSUE: The global transportation industry is undergoing a profound transformation, driven by the rapid adoption of battery-electric-powered vehicles across multiple sectors. However, this progress brings new and unique challenges relating to safe designs, operations, and specialized training for first responders. Throughout history, changes in energy sources have been accompanied by concerns and challenges that need to be addressed. Just as the rail industry successfully transitioned from steam to diesel locomotives, the next generation of rail transportation must adapt to meet the demands of continued advancement.
BESS in Transportation
Battery Energy Storage Systems (BESS) have long served as the underlying power source for electric automobiles. Their success in passenger vehicles has paved the way for broader applications, including fleets of electric buses in major urban centers and emerging BESS-equipped locomotives and passenger trains. While these technologies promise lower emissions and operating costs, they also pose complex safety considerations, particularly in the event of system failures or fires.
Multiple lithium-ion battery fire incidents have been documented globally, shedding light on the unique challenges posed by these systems. Data from the U.S. National Transportation Safety Board indicates approximately 25 fires for every 100,000 electric automobiles sold, compared to approximately 1,530 fires per every 100,000 gas-powered vehicles sold.[1] Additionally, out of approximately 250,000 battery electric buses in operation worldwide, only 27 battery fires have occurred as of January 2024.[2]
Recent examples include nine lithium-ion buses catching fire in October 2024 while being stored in a depot in Taiwan.[3] Another example was a fire that occurred in March 2024 at the San Diego Airport parking garage where three hybrid airport shuttle vehicles were stored.[4] Similar to automobiles, non-battery bus fires have a higher frequency, with an estimated 1,075 bus fires a year.[5] Although automobile and bus battery fires are rare, they can have a large impact from occurring unexpectedly, and emergency responders have problems putting out the fire.
Due to the limited deployment of BESS powered locomotives and passenger trains to date, there are limited incidents to report. However, there were important lessons learned in the 2000s, when battery switching locomotives entered operation. One of the most prominent suppliers at the time was Railpower Technologies, which produced the Green Goat, a 100% battery-electric switching locomotive. After suffering multiple high-profile battery fires, the delivered 59-battery switching locomotives were recalled. The cause of the fires was never officially released, but it is fair to say that a switching locomotive’s shock and vibration environment is one of the most difficult in the transportation world, and having a robust BESS design that withstands that demanding service is critical. Following the fires, a different switching locomotive design was introduced using multiple Genset diesel generators that could turn on and off as needed to meet demand and shut down during idle time.
The risks associated with lithium-ion batteries extend beyond vehicles to passengers and cargo. Micromobility is a term used for small personal transportation devices that utilize lithium-ion batteries, such as e-bikes and e-scooters. In January 2024, an e-bike brought onboard a Toronto Transit Commission subway train caught fire. Luckily, no serious injuries occurred.[6] Another example occurred in September 2024 when a freight train carrying an intermodal container experienced a fire of the lithium-ion battery lading. To put out the fire, a hole had to be cut in the top of the container and 40,000 gallons of water was pumped in.[7]
Understanding the Complexity of Battery Failures and Fires
An important aspect of BESS in transportation systems is ensuring it can withstand operational environments to avoid failures. High shock and vibration conditions are a common problem where heavy batteries need to be properly secured to ensure that external or internal damage doesn’t occur causing electrical shorts or other failure modes. Another environmental effect that is important to address is water condensation causing electrical shorts, which can occur after a warm vehicle returns to a cold depot during the night.
Lithium-ion battery fires differ significantly from conventional fires. While traditional fossil fuel fires can often be contained with standard measures like water, foam, or chemicals, lithium-ion fires can reach extreme temperatures and reignite hours or even days after being initially extinguished. These complexities stem from a phenomenon known as thermal runaway. Thermal runaway refers to an escalating chain reaction within the battery cells: once a single cell ignites or breaks down due to excessive heat or physical damage, it can rapidly transfer heat to adjacent cells, causing them to short-circuit in turn. The outcome is a rapidly intensifying fire that is extremely difficult to contain if responders are unprepared or lack the proper equipment.
Responding to a thermal runaway BESS fire has multiple unique problems. This risk is amplified when the event occurs in confined spaces such as tunnels and parking structures. Current methods in use to respond to lithium-ion battery highway vehicle fires include direct water spray on batteries, submerging an entire automobile in a water tank and utilizing fire blankets to buy more response time. Unfortunately, in the case of automobile and bus vehicle battery fires, sometimes letting the fire run its course until it fully consumes the vehicle is the only option. This is obviously not a viable option for railway vehicles, and as such, research and implementation of preventative designs and alternative emergency response strategies is needed.
Conclusions
Implementation of BESS in the rail industry presents opportunities to achieve operational and energy goals. However, with its unique characteristics, it also requires unique designs, operations, and emergency response practices. The rail industry can leverage shared problems with the highway vehicle sector to overcome them. This may include common standards, design practices, verification testing and emergency response training and equipment.
To facilitate collaboration across transportation modes, the Transportation Technology Center will host the TTC Battery Safety Summit on May 19-20, 2026. The event aims to bring together stakeholders to discuss and achieve advancement in battery safety. For more information, visit ttc-ensco.com.
References
- https://news.med.miami.edu/electric-vehicle-fire-staged-to-study-environmental-health-ramifications/#:~:text=Data%20from%20the%20U.S.%20National,100%2C000%20gas%2Dpowered%20vehicles%20sold
- https://www.evfiresafe.com/post/why-do-e-buses-catch-fire
- https://www.taiwannews.com.tw/news/5956072
- https://www.firerescue1.com/lithium-ion-battery-fires/li-ion-battery-fire-destroys-shuttle-buses-in-san-diego-airport-parking-garage
- https://www.nfpa.org/education-and-research/research/nfpa-research/fire-statistical-reports/vehicle-fires
- https://globalnews.ca/news/10199944/e-bike-fire-ttc-subway-safety-concerns/
- https://www.firehouse.com/operations-training/video/55137102/rail-cars-carrying-lithium-ion-batteries-burn-in-sutter-county-ca
