Hydrogen-fuelled rolling stock: understanding the risks

'If done right, the introduction of hydrogen-fuelled trains could bring benefits for industry,' says Darren Fitzgerald, RSSB’s principal rolling stock engineer

Hydrogen power in rail

Darren Fitzgerald
Principal Electrical and Systems Rolling Stock Engineer, RSSB

Hydrogen can power trains when used in a combustion engine or a fuel cell. The rail industry’s sustainability goals and the Rail Industry Association’s 2024 net zero strategy highlight that hydrogen is an option for some routes. However, hydrogen is often seen as a complex fuel with a high risk due to past accidents with hydrogen in other industries.

The benefits of using hydrogen as a fuel, such as it only emitting water vapour and warm air, are clear. This is what makes it eco-friendly. Still, the risks, along with the costs associated with installing the supporting infrastructure and the supply of hydrogen, often outweigh the rewards in a business case.

Hydrogen trains are, however, running in the Canada and Europe.

In Quebec, a hydrogen train carried over 10,000 passengers for a short period of time to prove that it is possible. In Hesse, Germany, hydrogen trains are in full passenger service, but a trial in Lower Saxony was less successful. In GB, there are mainline-approved hydrogen vehicles, but they are not yet in passenger service.

In 2021, we published a report on standards and legislation gaps. We also discussed the legal implications of a hydrogen safety event, with case studies. The report aimed to assess if current standards could manage the risks of hydrogen systems and clarified boundaries between all parties involved in safely operating hydrogen systems.

We have since published three more reports on the risks of hydrogen-fuelled trains. We’re committed to helping the industry weigh the pros and cons of using hydrogen. The first report defines the system and its parts. The second is a model for risks and consequences of hydrogen leaks. The third covers policy, standards, and legislation relating to hydrogen-powered trains in GB.

A system definition sets the boundaries of the onboard hydrogen system, including compressed gas storage. It helps the industry understand its responsibilities, especially parties designing and maintaining rolling stock.

Those who are exploring hydrogen in industry have already used the risk tool developed in the project to benchmark their existing work. The model focuses on the loss of hydrogen containment, and it lists threats, such as hydrogen remaining in an unloading hose, with consequences, such as ignited vessel ruptures.

The policy element, meanwhile, reviews all standards and legislation that may apply to a hydrogen-fuelled train. It simplifies the

application of both the Control of Major Accident Hazards (COMAH) 2015 Regulations and the Planning (Hazardous Substances) Regulations (PHSR) 2000. It also provides a calculator to help users understand whether the regulations are likely to apply.

Each organisation will, however, need to build on this work based on where they are in their hydrogen journey. International standards on hydrogen rolling stock will be published in the next 12–24 months, which will help. Additionally, the industry must also learn from other sectors, such as automotive and bus, where hydrogen deployment has had mixed results.

If done right, hydrogen-fuelled trains can help decarbonise routes needing a longer range than current battery technology is capable of providing. However, this will only be possible if there is a strategy for hydrogen in rail and if infrastructure managers, operators, suppliers, and emergency services work together.

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