Traction

The T1145 project evaluated the carbon impacts of existing and future fuel or /energy sources including the carbon grid mix of electrification.

In February 2018 the then Minister for Rail challenged the rail industry to remove diesel-only trains from the railway by 2040 and to produce a vision to decarbonise rail. 

The project identified that beyond electrification and diesel, only hydrogen and battery options would be sufficiently mature by 2040 to support rail decarbonisation, without impacting network operational and timetabling requirements. 

While it is possible to remove diesel-only passenger trains by 2040, there are no suitable alternatives, either currently or on the horizon, to diesel freight trains on routes which are not electrified.

This project improves the clarity on options for rail traction decarbonisation and their practical implications, with a robust understanding of the traction options suitable for different journey requirements. In addition, the economic model is a sound tool to undertake initial feasibility assessment of options on a whole-life basis to generate economic and carbon benefits. 

Following this research a subsequent project (T1160) was commissioned to address the challenge of how to replace and/or modify the existing diesel fleet of freight locomotives with less carbintensive solutions while reducing other air pollutants.

The T1160 project examines the challenge of how to replace and modify the existing diesel fleet of freight locomotives with less carbon intensive and air polluting solutions.

The main objective was to define efficient roadmaps for the UK Rail freight industry to move towards decarbonisation, balancing the commercial elements of rail freight. 

Although the focus is on decarbonisation, the study also looks at reductions in air quality pollutant emissions, most significantly NOx and PM. 

Key findings were:

• replacement of the current rail freight locomotive stock with more efficient diesel locomotives would lead to a reduction in well-to wheel GHG emissions by 12% on current levels.
• railway electrification is the most robust and effective method of rail freight decarbonisation.
• there is potential to use alternative self-powered options for rail freight such as natural gas, battery and hydrogen traction. But despite there being no major technical constraints to the deployment, they require a significant change in current operations and infrastructure requirements.

The T1172 project examined the regulatory framework for hydrogen trains, identifying gaps that are not covered by existing Codes of Practice (COP), and aims to clarify the regulatory steps needed for their introduction.

Although hydrogen has applications in other transport modes (including in buses and cars), the lack of a framework for use in rail presents a major obstacle to a safe and timely introduction of hydrogen powered trains onto the GB network. Hydrogen-powered trains have been identified as part of the solution to removing diesel-only trains from the network. 

This piece of work identified hazards and corresponding mitigations of hydrogen trains. Out of a total of 114 unique hazards identified, only 7 were found to be fully covered by existing rail industry COPs.

These gaps were categorised into three main groups, where current:

1. Legislation for hydrogen systems doesn’t fully address the operational and physical environment of the railway.
2. Standards do not explicitly define clearances between the hydrogen power system’s components, and positioning of the hydrogen power system in relation to passengers.
3. Standards and knowledge do not provide specific engineering values and parameters for the effect of catastrophic hydrogen accidents on the infrastructure.

In conclusion, developing an industry-wide framework for hydrogen trains will significantly ease the process of introducing the technology to the GB network. The final report makes detailed technical recommendations about how these gaps may be addressed.

The T1199 project aimed to assess the role and costs of trackside battery systems and hydrogen supply for nonelectrified rail routes.

Hydrogen-powered trains have been identified as part of the solution to removing diesel-only trains from the network. This study provides data and insight into the role and costs of trackside battery systems and hydrogen supply for those track sections that do not justify full electrification purely on economic grounds. 

The study found that the use of lineside batteries to support dynamic charging will depend on local requirements but may have limited applicability. However, lineside batteries may have a role when colocated with solar generation and when supporting stationary fast charging applications. 

It also found that dynamic charging of battery trains will likely be more expensive than stationary charging per unit of energy supplied. But this is expected to be considered useful because it minimises operational impacts caused by charging operations.

On-site hydrogen generation by electrolysis may be more economic than current off-site generation alternatives in the short-term. However, the cost of off-site generation from renewable sources or from industrial production plus carbon storage and capture is likely to decrease progressively by 2050, which makes the latter the most cost-effective options in the long-term. 

Unfortunately, the likelihood of finding sufficient space for renewable generation in urban rail depots is low, therefore a grid connection is the most likely to run an on-site electrolyser located at the depot. However, hydrogen produced at renewable energy hubs close to rail depots is a promising source of green hydrogen for urban rail depots.

The outputs of this project inform decisions on the practical requirements for hydrogen and battery infrastructure in depots and other areas where hydrogen and battery trains are being considered for deployment.

The project T1195 plans to deliver outcomes that build on existing information to establish the current gaps and opportunities for approvals of battery trains. This project is specifically focusses on understanding the safety, and wider system considerations that are key for making sound decisions for potential future battery use for rail traction.

This project includes:

1. A literature review which summarises the current and expected future capabilities of the technology and how it’s being applied in different industries and different regions.
2. A high-level operation concept to define relevant systems and operations.
3. Identification of the specific hazards associated with battery trains, alongside specific mitigation strategies.
4. Creation of an approvals route map to identify requirements and shape further standardisation.