On the right track for a sustainable rail network

The challenge of climate change demands immediate action, and sustainable development is only as good as the measures put in place at project outset. Identifying which projects deliver the greatest social and environmental returns for each ‘pound in the ground’ will bring about change with meaningful impact, says Samuel Seabrooke.

Rail is already a relatively low-carbon form of transport but addressing its residual carbon footprint is only one piece of the sustainability puzzle facing the industry. Is the sector prepared for the impacts of climate change on its operations, as well as rising passenger numbers and changing end-user demands? The answer is “not entirely”.

To keep pace with rising demand, new rail schemes are being delivered in many countries and across continents, but in the UK, most routes were built at a time when climate change wasn’t an issue, and its effects were certainly not considered in the legacy of the railway’s design. So, the challenge facing the industry is to ensure new schemes, assets and operations are low carbon and climate resilient, while also enhancing the social and environmental aspects of the sustainability of existing infrastructure and operations.

Alternatives to full electrification

Full electrification of lines will reduce operational carbon. However, the high capital cost is driving new innovations in discontinuous electrification, facilitated by advancements in energy storage technology and alternative hydrogen traction.

Partially electrified railways are feasible for most passenger services and only require relatively small and strategically placed route segments of overhead electrification, with the remaining energy demand provided by on-train storage. Considering discontinuous electrification as an alternative or interim solution to full electrification will reduce the overall cost and capital carbon of schemes, all whilst reducing service disruptions and providing a faster route to decarbonisation.

Where additional capacity is required, any large, new infrastructure project should be reviewed to determine whether changes to the existing network – such as installing modern signalling systems or modifying timetables – would provide a viable alternative. This approach is in line with the Mott MacDonald co-authored public standard, PAS2080, which includes a do nothing, do less, do more efficiently hierarchy for embodied carbon reduction.

Local services

The average UK rail journey in 2019 was around 64km, suggesting that improvement of local services is key to create a greater modal shift to rail and other forms of public transport. Schemes to link major cities via highspeed rail services should therefore also deliver better services and improved connections for local communities along the route.

Reinstatement of lines and stations or addition of new ones, matched by a suitably frequent and reliable service, can be a catalyst for sustainable development via community enhancement – for example, increased access to job opportunities, improved social inclusion and a reduction in carbon. It is also an opportunity to reimagine stations, so they don’t only exist for the provision of rail services, but are also places to access active travel routes and options for interconnected travel services.

Design and delivery

Incorporating sustainable elements into the early project design is key to reducing carbon and environmental impacts, and maximising social outcomes. The PAS2080 guidance sets out good practice for carbon reduction, starting with ‘do nothing’, though that option will rarely deliver the technological and societal changes needed to decarbonise. New tools from across the Rail industry will also aid engineers in appreciating the value of Social Outcomes and aims to encourage their inclusion within projects.

The nature and scale of railway systems means the impact on the environment is relatively large. Minimising it demands a cohesive approach between people and nature. Where structural foundations alter the ground or route clearance negatively affects the environment, the project should identify the sensitive social and natural receptors, with respect to noise, pollution, biodiversity and habitats, at the outset. The outputs of such analysis would impose design constraints on engineers during development and guide the overall solution.

User-friendly tools to enable engineers to access this key data are available to help, such as the Mott MacDonald developed Network Rail climate change tool. As wind, rain and temperatures climb to new extremes, a railway built today must be able to operate safely for many years, and our tools enable designers to deliver solutions that are resilient to future extreme weather conditions caused by climate change.

Recent extreme weather events in Germany, Italy, China and the US highlight that no country is safe from the impacts of climate change. We need global and industry collaboration and open working to accelerate the delivery of transport decarbonisation, including more sustainable rail infrastructure and operations.

Leaving a legacy

From the Stockton and Darlington line to the Great Western Railway, rail has left a legacy for the people and places it connects. To maintain this legacy, while also delivering on safety and efficiency targets, rail owners and operators need to continually monitor the condition and performance of their assets.

As wind, rain and temperatures climb to new extremes, a railway built today must be able to operate safely for many years.

Samuel Seabrooke

Overhead contact system engineer at Mott MacDonald

Condition monitoring of earthworks can help detect subsidence or slippage, preventing potential rail disaster, while digital twins – realistic digital representations of physical assets like rail equipment and the land supporting tracks – provide asset owners and operators with the information to make right-first-time decisions. Designers benefit from higher levels of data certainty provided by the digital twins, enabling them to accelerate solutions and proposals.

Developing and recording project aspects through digital twins is facilitated by software such as Moata Geospatial, our digital tool for mapping information across large project areas, and Moata Carbon Portal, our solution for calculating and reducing embodied carbon in new assets. Data from both tools can integrated with 3D BIM models, and are essential to improving the efficiency of project delivery.

And so, as we emerge from COP26 in Glasgow, governments and the private and public sectors must now work together to ensure the future of railway project delivery and operations is sustainable by embedding this ethos within schemes.