By Salma El-Sakka
A fleet of 36 taxpayer-funded tram-trains costing more than £200m has remained largely unused for over three years since the first unit arrived in Wales, according to data obtained by the BBC.
The Class 398 Citylink units, ordered from Swiss manufacturer Stadler in 2018, were originally promised to be fully operational by 2022. Transport for Wales (TfW) now says full service across the 105-mile South Wales Metro network may not begin until the end of 2027.
Testing and reliability challenges
Only 16 of the 36 trains have passed statutory safety testing required by the rail regulator, with the remaining 20 still undergoing scrutiny that can take between six weeks and two years per unit. TfW chief executive James Price said the operator wants trains that work "100% well, 100% of the time" before full deployment. Six tram-trains are currently in passenger testing but have been temporarily withdrawn for software-related "teething issues."
Infrastructure and cost pressures
The South Wales Metro project, Wales' largest infrastructure scheme since devolution, aims to transform Victorian-era lines into a turn-up-and-go rapid transit system. Electrification of the network was completed only in March, delayed by the Covid pandemic and supply chain disruptions from the Ukraine war. TfW says using on-board batteries for non-electrified sections saved about £400m and years of construction time.
Criticism and political response
Opposition politicians have questioned why most of the fleet is "just sitting in a depot gathering dust." Reform's shadow transport minister Jason O'Connell called for transparency on delays and spiralling costs. Rail engineer Gareth Dennis suggested the tram-trains' complexity — combining tram, train, battery and discontinuous electrification — may be overly ambitious.
Rollout timeline
Price said he expects four trains per hour on the three core valley lines by the end of 2025, with the full tram-train fleet entering service by the end of 2027. The Welsh government stated TfW remains on target to complete the full rollout by the end of next year, adding that transformative improvements have already been delivered on the valleys network.
