Decarbonisation of the UK’s railways

Climate change is one of the greatest challenges faced by the modern world. The Intergovernmental Panel on Climate Change’s report from the world’s most eminent climate scientists warns of rapid and potentially catastrophic changes to our planet. With wildfires this year in Greece, Turkey, Russia, and the US, governments and businesses around the world are under growing pressure to not only deliver measures to tackle the challenge, but to speed them up.

The Department for Transport’s (DfT) Decarbonisation Plan was published in July 2021 and currently serves as a blueprint for the transport sector to achieve net-zero by 2050. In particular, the Decarbonisation Plan sets out how the government intends to decarbonise the railway.

The plan states: “With electrification, plus batteries and hydrogen, we can achieve a net zero emission rail network by 2050” and reiterates the ‘ambition’ to phase out diesel-only trains in England and Wales by 2040.

Alongside the Decarbonisation Plan, the DfT also published the Rail Environment Policy Statement which sets a clear direction for the rail industry on environmental sustainability in relation to the mainline railway and outlines policy priorities for the forthcoming Sustainable Rail Strategy.

Credit: SkedGo | MOTIONTAG

The removal of diesel-only trains from the network will have multiple benefits, including reducing greenhouse gas emissions, air and noise pollution, cutting operational costs, and improving performance. This will be no small feat. The Rail Industry Decarbonisation Taskforce, with support from the Rail Safety Standards Board, estimated in June 2019 that approximately 3,000–3,300 diesel passenger vehicles will need to be replaced, re-engineered, or converted, to decarbonise the railway.

The railway is already one of the lowest-carbon modes of transport for passengers and freight. According to the Office of Road and Rail, 38% of track in the UK is electrified. As noted in the Williams-Shapps Plan for Rail, electrification is a proven and existing technology and will play a key role in decarbonising the network – although this of course depends in part on the fuel mix for the power stations that generate the electricity used.

Further routes for electrification will be determined based on sustainability and cost-effectiveness. The DfT will be guided on which technology to deploy to each route by Network Rail’s Traction Decarbonisation Network Strategy (TDNS). The DfT is due to announce further electrification schemes shortly, which will be led by Great British Railways once it is established in 2023.

The TDNS identifies a series of transitional solutions and final solutions required to achieve net-zero by 2050. One of these is the greater utilisation of the existing electrified network, with a focus on improving power supplies to sections of track that have electrified infrastructure but have poor supply, limiting the number of vehicles they can support. This is likely to require a significant number of power supply upgrade projects.

It is likely Network Rail would undertake such projects where it can, using its existing statutory powers. A full solution is the further electrification of the parts of the network that are not electrified. However, electrification is costly, complex, and disruptive.

Where electrification is not feasible, the focus is on the use of alternative traction options such as electric batteries or hydrogen power. There are advantages and disadvantages to both, not least the constraints on longer and high-speed journeys. On the plus side, existing rolling stock can be refitted to accommodate these alternative power sources. Both of these options are being urgently explored and developed.

The HydroFLEX- the first hydrogen-powered train in the UK – has been developed by Porterbrook in partnership with the University of Birmingham, by refitting a former electric train with a hydrogen pack. The HydroFLEX successfully completed its mainline testing in September 2020 and has been showcased at COP26.

At COP26, Vivarail also showcased its fast-charging battery-electric train. These battery-electric trains have been designed to charge at stations and depots and only draw power when required. These trains are best used for commuter and regional services and are already in use on the Isle of Wight’s Island Line and the West Midlands Railway between Bedford and Bletchley.

In terms of the legal implications for making significant changes to the infrastructure on the network and rolling stock that operates on it, it will be necessary to review the original legislation that authorised the relevant railway lines, to see if there are any restrictions on the type of rolling stock or power sources which can be used on each line, which may need to be addressed.

Furthermore, significant changes to infrastructure and rolling stock are likely to engage safety requirements under the Railways and Other Guided Transport Systems (Safety) Regulations 2006.

The TDNS provides guidance on what changes Network Rail considers appropriate for each geographical area and railway line. Rail operators should therefore consider the routes they operate on and what the TDNS has recommended for each route to gauge what improvements may be forthcoming.

In addition, rail operators will need to review their existing rolling stock and approach to the procurement of future rolling stock to consider what changes are likely to be needed to ensure they are doing their part in the UK achieving net-zero by 2050. Those at the centre of the transport infrastructure will need to be ready to adapt their plans to meet the potential tightening of the timetable for the change to a carbon-neutral infrastructure.