Nexus has been running the Tyne and Wear Metro for over 40 years. The trains have changed, the stations have been modernised, and passenger expectations have shifted enormously. Now, the control technology running behind the scenes has caught up.
There is a version of infrastructure renewal that gets a lot of attention. New trains, station redevelopments, electrification schemes. The kind of work that passengers notice and politicians announce. Then there is the other kind. The work that happens in control rooms, relay rooms, and equipment cabinets that most people will never see, carried out by engineers who largely prefer it that way. This is a story about the second kind.
Sella Controls, a HIMA Group company, has completed the renewal of the Supervisory Control and Data Acquisition (SCADA) system for Nexus, the passenger transport executive responsible for operating the Tyne and Wear Metro. It is not a glamorous headline – but it matters considerably. The SCADA platform is the operational brain of the network. It is how control room staff see what is happening across the traction power infrastructure, how they respond to faults, and how they make the thousands of small decisions every day that keep services running on time. When that system is ageing, unsupported, and increasingly difficult to maintain, the risks compound quietly. The Nexus SCADA renewal was a considered, well-planned piece of infrastructure investment, and it has been delivered well.
Why it was needed
The Tyne and Wear Metro has been running in some form since 1980, and over the decades its importance to the North East has only grown. Rising passenger numbers placed increasing demands on the teams responsible for keeping the network running. As journey volumes climbed, the ability to supervise and control critical operational assets became a priority, not just a convenience. However, the legacy SCADA technology was not keeping pace. Spare parts were scarce, software was no longer receiving updates, and the system simply could not give operators the real-time visibility that modern railway operations require.
Nexus went to market for a modern, flexible solution, supplied by a contractor with proven competence in SCADA, a track record in complex systems integration and migration, and a demonstrated ability to deliver programmes of this kind. Sella Controls was one of several established providers assessed. In the end, it was not just the technical capability of the TrackLink Traction Power Management System that won the contract – the approach mattered too. Nexus wanted a partner willing to work closely and openly throughout the programme, not just a supplier delivering to a specification. That commitment to genuine collaboration was central to the winning proposal.
What Sella Controls brings to the table
To understand what was involved, it helps to know the network. The Tyne and Wear Metro covers five metropolitan boroughs: Newcastle upon Tyne, Gateshead, North Tyneside, South Tyneside, and the City of Sunderland. It serves 60 stations across its route and operates on a 1500VDC traction supply. A 33kV incoming feed is stepped down to 11kV, and that 11kV network distributes power across the system. Local substations contain transformer and rectifier equipment to provide the DC traction supply and an auxiliary three-phase supply for station services. That includes lighting, lifts, escalators and fire alarms, meaning the scope of the system extends considerably beyond traction power alone.
Sella Controls was commissioned to replace 47 sites across this network. Each site received a TrackLink RTU panel, sized appropriately from small, medium, or large depending on the substation’s requirements, and fitted with an integrated uninterruptible power supply to keep the unit available every hour of every day.
The RTUs feed live data into the TrackLink SCADA platform, which gives infrastructure controllers a continuous real-time view of the network and actively calculates the live power load. Operational staff can see the state of the network as it changes and make decisions on the basis of what is actually happening, rather than working from incomplete or delayed information.
“This project is a major investment in new technology for our Metro control room and is vital for Metro’s long-term future,” says Paul Welford, major projects director at Nexus.
“It is a project which has been meticulously planned over the last two years to ensure the least possible amount of disruption to our customers. Sella Controls have provided us with amazing support during the transition to this new digital technology.
“The SCADA system is essential for the safe and effective operation of Tyne and Wear Metro. It enables us to remotely manage the high and low voltage power supplies and other key things like lighting, lifts, escalators and fire alarms. It will allow us to resolve infrastructure issues more effectively, which will mean less disruption for our customers.”
The system also does more than watch. Nexus operational staff have access to a fully equipped training simulator at the Nexus Learning Centre, where teams can get familiar with the platform and rehearse fault scenarios without any risk to live operations. For maintenance engineers, the platform provides network-wide analytics accessible from their own workstations, with the ability to filter right down to individual device level. That changes the nature of maintenance work. Rather than responding to failures after the fact, engineers now have the tools to spot developing issues early and act before they become service-affecting problems.
The system architecture has also been designed with future growth in mind. The electrical live model at its core means enhancements such as remote securing can be incorporated without requiring significant rework, protecting the value of the investment as operational requirements evolve.
For Nexus, the result is a genuine step change in what the operational team can do. Control room staff have a clearer picture of the network than they have ever had, fault conditions surface faster and with more context, with the interface being built around how operators actually work, rather than asking them to bend their processes around the system’s limitations.
“We recognised very early in the pursuit process what the Nexus team wanted from a delivery partner,” says Chris Elliott, sales director, global account management rail, Sella Controls.
“We believed our strongest differentiator was our overall engineering competence, experience, and proven track record in delivering this type of project, alongside the technical capability of the TrackLink Traction Power Management System.
“I firmly believe we delivered on the commitment we made during the tender assessment process, providing a flexible approach, working in partnership with the client, and executing the project on time and to budget.”
Delivering on a live railway
The hardest part of a project like this is rarely the engineering. It is the sequencing. You cannot take a live control system offline, replace it, and bring the new one up. The railway is running. Services depend on that operational visibility.
Nexus awarded the contract on the basis of an 18-month programme covering design assurance, build, test, and commission, with decommissioning of the legacy assets to follow. To meet that timetable, Sella Controls put together a dedicated delivery team and managed the programme end-to-end, working closely with all external suppliers to keep the work on track.
The system was commissioned progressively, section by section, with each stage signed off before the next began. Factory acceptance testing, site commissioning, and the final migration were all planned around the reality of a railway that could not stop running. The fact that the Metro kept running reliably throughout is a good measure of how carefully the project was managed on both sides.
Benefit to passengers
Passengers will not notice the new SCADA system. What they will notice, over time, is a more reliable service and faster recovery when disruption does occur. When a fault develops on the traction power network, the speed at which operators can identify it and respond directly affects how long people wait on a platform. A well-designed SCADA system does not stop faults from happening. It gives the people managing the network the tools to deal with them quickly. On a network carrying more than 30 million journeys a year, that matters. For maintenance teams, the improved access to asset data also opens up more intelligent ways of planning work, reducing both cost and disruption over the life of the system.
Collaboration that delivers
Projects like this do not succeed on technical merit alone. On a live operational railway, with real consequences for disruption, what actually makes the difference is the quality of the working relationship. Sella Controls and Nexus approached this programme with a level of transparency and shared ownership that is not always seen. Problems were raised early. Decisions were taken jointly. Both teams stayed focused on what the project needed to achieve rather than what was written in the contract.
That matters because the hard moments in any complex systems integration do not follow a schedule. They turn up during testing, during commissioning, when reality diverges from the plan. When the working relationship is built on honest communication, those moments get resolved rather than escalated. The Metro got a better system for it, and both organisations came away with a clear understanding of what had been built and why it works.
Sella Controls brings over 100 years of combined expertise in Traction Power SCADA control, and that depth of knowledge is what allows us to deliver complex system renewals with confidence. As part of the HIMA Group, we can draw on safety and control systems competence from across the globe, which means clients anywhere in the world benefit from the same level of engineering rigour that we applied here on Tyne and Wear Metro.
Built to last and to grow
The TrackLink Traction Power Management System is not a closed system. Its open architecture and modern interface standards mean Nexus has a platform to build on as operational requirements develop, not just a replacement that kicks the problem down the road. Projects like this rarely make the front pages. But the Nexus SCADA renewal is a good example of what infrastructure investment done well actually looks like, delivered on time, on a live railway, by people who understood what the operator needed. It is the kind of work that keeps a city moving.
“Sella Controls brings over a hundred years of combined expertise in Traction Power SCADA control, and that depth of knowledge is what allowed the delivery of complex system renewals with confidence,” says Chris.
“As part of the HIMA Group, the business drew on safety and control systems competence from across the globe, which means clients anywhere in the world benefit from the same level of engineering rigour that Sella Controls applied here on Tyne and Wear Metro.”
Image credit: Sella Controls