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The global rail infrastructure market is expected to reach $1.2tn in 2026. This will be made up of investment in major projects already underway or in planning and it spans every continent.

From new high-speed lines and local metro systems to upgrades and capacity enhancements on existing lines, the sector is faced with several challenges including carbon mitigation and reduction; the ever-present need to tackle escalating projects costs; and ensuring successful and predictable delivery over what can often be very long project timeframes.

This all starts with the ground on or under which a scheme sits. As is widely recognised, projects rarely have sufficient ground investigations. A key historic reason for this was that such investigations presented a costly challenge that, even with the best intentions, could leave significant gaps in knowledge across a project team. Fortunately, new technology may be changing that.

Subsurface route determination

One area in which technology can help with deliverability of projects is at the very earliest stages – route selection. This can be key to identifying the most effective means to deliver the project, as well as potentially lower its carbon and improve its safety.

This became evident with plans for the new high-speed line proposed between Gelnhausen and Fulda in Germany, intended to accommodate a 30% increase in passengers by 2030 via a new double-tracked route northeast of Frankfurt. Services will run at up to 240 km/h and the longest tunnel proposed is 9.5km long.

Specialist civil and geotechnical engineering consultancy, Prof. Quick und Kollegen was commissioned by Deutsche Bahn Netz to determine the optimal rail route and explore the geotechnical feasibility of tunnels, while protecting the local environment and community.

Prof. Quick und Kollegen geologist Thomas Schneider explains: “We conducted subsurface investigation for two possible routes, approximately 50km each, with about two thirds of the total 100km route running in tunnels.”

These tests included exploration of over 100 boreholes and 15 lithological layers across what was an incredibly complex fault system. This resulted in extensive complex subsoil data, leading to coordination challenges, according to Schneider, especially when combined with archived records.

“Through our field investigations and official archival records, we gained good geological insights to help us understand the underground element of our project area. However, this information was only available in 2D format and often only viewed in isolation.

“Accurately representing the complex subsoil to include all 88 fault blocks was a major concern for our team.”

This led to efforts to adopt 3D modelling, although there were questions about whether this could even be done. “We were unsure if any software – even Leapfrog Works – would have the capabilities but were excited to discover it did and the Bentley and Seequent teams worked closely with us to tackle this challenge.”

Using Seequent’s Plaxis geotechnical analysis software and Leapfrog Works, the project team established a 3D model that Schneider believes was crucial to the project’s success, delivering “the highest possible standard of productivity, efficiency and safety with the best ecological and economical solutions”.

Lessons in risk management

While the ability to plan the use of subsurface materials is proving invaluable in some projects, one of the big opportunities in 3D ground mapping has emerged from its application to risk resilience across a project.

Rail and road projects can cover long distances and involve a large number of active participants. They can also run for many years, which means some have seen the emergence of 3D modelling mid-project.

This was the case on City Rail Link (CRL) in Auckland, New Zealand, due to open in 2026. This project, which started in 2012, involves 3.5km of twin rail tunnels at depths of up to 42m, with new and expanded stations along the route as well as wider rail network improvements.

Along with geological uncertainty, urban projects often come with additional subsurface challenges due to unmapped or inaccurately mapped subsurface infrastructure. They also present the natural challenges of extensive geological uncertainty.

CRL began with the construction of the north tunnel portal in the city’s central business district (CBD), when geological planning used traditional mapping. But over the project’s construction phase, this has changed dramatically.

Aurecon is principal technical advisor to that project, and its technical director of ground and underground engineering Philip Kirk explains: “We did that [the north portal] largely by traditional means – a lot of drawings and reports. Then we moved to the south portal and issued a geological model for information purposes only, to benefit the tenderers to help them understand the traditional documents.”

That proved so popular that the project changed approach.

“The tenderers for the main works, which we did last, requested a 3D model for the rest of the project and we’re not going back to the traditional ways,” says Kirk.

City Rail Link in Auckland, New Zealand, transitioned from traditional methods to 3D modelling of geological data mid-project

Change is its own challenge

For many stakeholders in a project, it can feel like a complicated process to transition to 3D underground models. This is especially the case when, despite their limitations, traditional methods have delivered in the past for those involved.

So, while few would argue that real-time collaboration and oversight are not benefits worth pursuing, and many would welcome opportunities to improve risk management and carbon reduction, change may not come easily.

Technologists need to be alert to that challenge, and Seequent is keen to recognise the role it must play by helping industry achieve better outcomes.

Seequent civil segment director Pat McLarin explains: “We are part of the infrastructure sector, and we are optimistic about what can be achieved through the application of technology. We create tools to help improve the transparency of information within projects, improve decision-making and long-term outcomes through a digital twin approach to the subsurface, to generate real outcomes like reduced carbon and risk.”

“However, our technology can’t do that if it isn’t usable or doesn’t meet the industry where it is today. That puts the focus on the technology sector and companies like Seequent to not just show people what the technology can do, but also inform them about which technologies they should be working with, and how they can adopt them.”

With this in mind, Seequent has created an ebook, Switching to cloud-based management, with information on why companies should make the transition. It emphasises the importance of data in modern ground investigation and highlights three key tasks: collecting accurate data, making it available to the right people in a timely manner, and using it to make informed decisions and create better designs.

“Making the switch well is just as important as making the switch at all. The opportunities that technology presents for better collaboration and delivery across projects need to be fully understood if industry is to realise them,” McLarin highlights.

eBook: Switching to cloud-based management

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