The short version
- Less than half of the 36-unit tram-train fleet has completed mandatory statutory safety testing three years after initial delivery.
- Transport for Wales prioritizes achieving near-perfect reliability metrics before expanding service, citing complex software integration challenges.
- The delay pushes full network coverage to late 2027, five years past the original target date set during the project's inception.
A major public infrastructure initiative in Wales has faced significant delays, with Transport for Wales announcing that its new fleet of tram-trains will not enter full service until the end of 2027. This timeline represents a five-year postponement from the original 2022 target date promised to commuters and stakeholders. The project, known as the South Wales Metro, is designed to transform an aging Victorian railway network into a modern rapid transit system comparable to services in London or Manchester. Despite the arrival of the first units in March 2023, the majority of the fleet remains idle at a newly constructed depot near Cardiff.
The financial scale of the endeavor is substantial, with the tram-trains alone costing more than £200 million. These vehicles are considered the final component of a broader £2 billion investment aimed at revitalizing transport across the south Wales valleys. Data obtained through freedom of information requests indicates that fewer than half of the 36 Class 398 Citylink units have passed the rigorous statutory testing required by rail regulators. Specifically, only sixteen of the three-carriage trains have been cleared for operation on the UK rail network, while twenty others are still undergoing scrutiny.
James Price, the chief executive of Transport for Wales, has defended the cautious approach by emphasizing a commitment to high reliability standards. He stated that the operator seeks vehicles that function perfectly at all times before introducing them to large numbers of passengers. The organization aims to maintain a 95% on-time reliability rate across the valleys network, a benchmark it intends to meet before expanding the tram-train service. This strategy reflects a desire to avoid the disruptions associated with early technical failures.
Technical challenges have centered largely on software integration rather than mechanical defects. Price noted that the entire fleet is controlled by a single, complex software package designed to automate many train functions. While this automation offers long-term benefits for maintenance and updates, it has introduced initial reliability hurdles. The operator described these as teething issues inherent in bringing such advanced technology into service. Software problems have occasionally forced temporary withdrawals of trains from passenger testing phases.
The testing process itself has proven lengthy and variable. Records show that statutory tests can take anywhere from six weeks to two years to complete, with some evaluations beginning only in 2024. This variability contributes to the staggered rollout schedule. Six units are currently undergoing passenger testing across parts of the valleys network, but their deployment has been intermittent due to the aforementioned technical adjustments. The remaining trains have been stored for up to three and a half years, raising questions about the efficiency of the procurement and deployment strategy.
Commuters on specific routes between Cardiff and towns such as Aberdare, Merthyr Tydfil, and Treherbert were initially told that service frequency would double from two to four trains per hour by 2022. That promise has now been pushed to the end of 2027. In the interim, Transport for Wales introduced Class 756 units onto the valley lines in 2024. Price indicated that these earlier deliveries arrived sooner and demonstrated better reliability, allowing the operator to prioritize getting functional trains into service rather than waiting for the tram-trains to meet original deadlines.
The South Wales Metro project is widely regarded as the largest infrastructure undertaking in Wales since devolution began in 1999. It seeks to modernize the historic Taff Vale Railway network, which once transported coal from local mines to Cardiff Docks for global shipment. The transformation aims to provide a turn-up-and-go service that integrates urban street running with traditional rail capabilities. High-profile figures, including King Charles and former Prime Minister Keir Starmer, have visited the new depot and tested the trains, underscoring the political significance of the project.
Efforts are underway to accelerate the remaining testing and deployment phases. Price recently met with executives from Stadler, the Swiss manufacturer that supplied the trains in 2018, to discuss speeding up the rollout. The operator has chosen a low-profile introduction strategy, avoiding major public launches for the tram-trains until reliability targets are consistently met. This approach aims to prevent service interruptions that could damage public confidence in the new system.
The delay highlights the complexities of modernizing legacy rail infrastructure with advanced technology. While the financial investment is significant, the operator argues that patience ensures long-term value and stability for passengers. The focus remains on achieving seamless integration of software and hardware before expanding service across the entire 105-mile network. As testing continues, the gap between initial promises and current realities serves as a case study in the challenges of large-scale public transport modernization.
Looking ahead, the full benefits of the South Wales Metro will not be realized until late 2027. Until then, passengers must contend with a transitional period marked by mixed rolling stock and ongoing technical adjustments. The operator maintains that the current strategy maximizes value for money by ensuring that new assets are fully functional before widespread use. The outcome of these efforts will determine whether the project meets its ambitious goals of transforming regional connectivity in Wales.
Sources behind this briefing
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- BBC News↗£200m taxpayer-funded trains sit barely used for three years
