Challenge
Transport for Wales is currently in the middle of a once-in-a-generation project to modernise travel for people across South-East Wales. The South Wales Metro aims to transform travel across the region, with more frequent and faster journeys made on brand-new trains. The project, alongside multiple other projects to improve buses, walking, and cycling routes, all aim to make Transport for Wales the favourite way for passengers to travel across Wales and its borders.
Working on behalf of the Welsh Government, over a billion pounds has been invested in updating the railway fleet, signalling systems, depots and control centres, along with new stations and infrastructure upgrades, to grow and integrate Wales’ transport capacity so people can simply turn up and go.
Across the South Wales Valleys, engineers are building a disconnected ‘Smart’ electrified railway network for a new fleet of tri and bi-mode trains. These cutting-edge trains run on overhead electricity along electrified sections of the railway; automatically switching to battery power on non-electrified sections of the network.
There are parts of the network where installing overhead wires would be prohibitively complex or costly, for example in tunnels, viaducts, or under low bridges. When running along these sections, the train’s pantograph lowers and is powered using an on-board battery which is then recharged when the train reaches an electrified section.
In addition, tram-trains will soon enter service, running along the Cardiff Bay line. The fully electric tram-trains can switch from running as a train on heavy rail tracks, to running as a tram on street-level with the press of a button, and are key for delivering future rail extensions like Cardiff Crossrail.
These projects involve a lot of digging up and diverting buried services out of the way of new electricity pylons. Piling into the ground to create the foundations for each pylon requires knowledge of all buried utilities and cables which could be impacted by the work. As railway transport is a historic industry, which celebrated its 200th birthday in 2025, it is not easy to obtain data about what lies underneath the ground ahead of excavation activities, increasing the risk of service strikes.
Solution
Transport for Wales began using NUAR as part of its safe digging process several years after the work to modernise and electrify the transport network across South Wales started. It was clear that NUAR would have been a great addition to the safe-digging process had it been available. Looking ahead at future projects, NUAR will be playing a key role as Transport for Wales embeds its use across staff and supply chain contractors.
NUAR is a government digital service that provides secure, instant access to a map of underground pipes and cables in England, Wales, and Northern Ireland. Operated by Ordnance Survey on behalf of the Government, it shares buried infrastructure data for telecoms, energy, gas, water, transport, and local authorities.
The map gives project managers better access to utility data and enables quicker planning for diverting or avoiding buried services. It gives excavators safer and more efficient on-site knowledge of services for installation, maintenance, operation, and repairs of buried infrastructure. It increases industry co-ordination, because NUAR is a centralised and secure platform that shares a standardised view of underground asset data on the map. And it increases operational efficiency through instant access to data, reducing multiple requests for information that previously took on average six days to obtain.
In 2025, Transport for Wales began using it for constructing a new railway station at Butetown on the Cardiff Bay branch line. The project required excavation for a new lift shaft and entrances for easy access to the station. By using NUAR, it became immediately obvious how much simpler and quicker it is for assessing diversions and identifying utility owners. Instead of relying on a collection of individual documents to interpret, the key information was all in one place on a screen.
As well as improving day-to-day safe digging processes, NUAR is also laying the groundwork for Transport for Wales to build an ‘Informative Twin’ of its utilities network. Because NUAR brings together multiple sources of underground asset data into one detailed map, it provides a digital replica of what lies beneath all its projects – be they bus, active travel, or railway. The incorporation of Transport for Wales Ground Penetrating Radar, and as-built plans into an in-house version of the conceptual data model used for NUAR called Model for Underground Data Definition and Integration (MUDDI). Which defines how different types of underground information can be described and related to one another—so data from many sources can be integrated, shared, and reused, means that Transport for Wales is building on NUAR’s foundation and aiming to build its own digital twin of its utilities network. This evolving digital twin enables engineers, designers, and planners to understand site constraints earlier, model construction impacts more accurately, and make better decisions long before work begins on site.
Result
If NUAR had been available two years earlier, it could have been used by project managers across South Wales to plan utility diversions to move pipes and cables out of the way to enable overhead line equipment to be installed safely. This would have been especially useful considering the amount of Victorian-era buried services found across the South Wales Valleys. It also would have helped improve planning for a myriad of supporting projects, such as the raising of bridge parapets to support overhead cables running underneath bridges. By identifying the owners of utilities that are contained within the highways, they could avoid significant costs should utilities need to be moved.
"NUAR turns an hour or two of study into a couple of minutes work."
Asset Engineer Dan Matthews said: “NUAR allows us to capture the coordinates of sewer chambers so they can be checked against our records. It's great to have the assets grouped by their discipline and asset owner, as this makes dealing with third parties much easier.”
Asset Engineer Shani Halilaj added: “We have been utilising NUAR to undertake searches for other utilities adjacent to our asset, to better understand interfaces between these assets, prior to planning any site works.”
Transport for Wales’s Utilities Coordinator, Ieuan Jones, said: “I am seeing an increase in requests for NUAR access on non-rail projects – such as bus and active travel. NUAR is helping our Project Managers gain confidence working with buried utilities outside of the rail corridor.”
“It will be able to assist us in areas such as digging for new bicycle lanes where you get so many different utilities. There should be more data on NUAR for those sorts of projects.
“There is very strong potential for the data to be used for planning purposes. For example, if we were planning to add a raised cycle network over a gas main, it would be very valuable to have this information so teams can do some smart designing that avoids these utilities.”
He added: “It is game changing in a lot of ways. The fact it's easy to use just lowers the barrier to entry. Any contractor can pick up their tablet and use it. When you demonstrate how to use the platform to project managers or people who have an interest in it, they understand it straight away. I think anyone doing safe digging should get an account.”
Another benefit discovered through NUAR has been how it can help with scenarios around working safely above ground.
Transport for Wales’s Utilities Manager, Irfon Jones, said: “We had an arborist contractor who had to cut down trees caught up in overhead fibre cabling. It wasn’t safe to pull down these trees with the fibre cable entwined in them. Using our usual methods, we couldn’t figure out whose overhead cables they were but through NUAR we discovered who owned them and passed the contact details on so the job could be done.”
Irfon added: “I have a GIS background and for me NUAR is intuitive and very easy to get up to speed with. Similarly, when it comes to uploading data, it’s been easy for me to do all of that.
“The Welsh language version of NUAR is a real positive example for others in the utilities industry to follow.
“I would 100% recommend it, especially in terms of safe digging to help people on site because they can look and see what is there, underneath their feet.”