Helsinki tram service disruptions are now affecting passengers after a recent increase in overhead line voltage caused damage to part of the city’s fleet. The central tram network will face daily cancellations throughout the week, as older units remain out of service while repairs continue.
Helsinki City Transport (Kaupunkiliikenne Oy), which operates the trams across the capital region, confirmed on Wednesday that although most trams are still running, the number available for weekday service has dropped below the usual level.
The issue began overnight between 13 and 14 September when the overhead DC voltage was raised from 600 volts to 750 volts as part of a planned system upgrade. The increase triggered failures in several older tram inverters. Inverters are vital because they convert direct current into alternating current, keeping the electrical systems of the tram functioning properly.
Antti Nousiainen, head of asset management at Kaupunkiliikenne, said that the delivery of spare parts is expected soon.
“We will receive more replacement parts next week. As soon as they arrive, we will be able to restore several trams to service quickly,” Nousiainen explained.
Repair teams are working to return the affected vehicles, but not all of the older articulated trams have been restored. This shortage has forced the operator to cancel services daily.
Passengers are advised that while the overall timetable has not been changed, they may face sudden cancellations. Real-time updates and service alerts are being published through the Helsinki Regional Transport Authority (HSL) website.
The transport operator expressed regret over the inconvenience caused to travelers and stressed that every effort is being made to keep disruption as limited as possible.
The voltage upgrade is part of a long-term plan to modernise Helsinki’s tram infrastructure and boost overall efficiency. The latest tram models can operate under the new 750 volt system, but older rolling stock has proven more vulnerable to the change. Until the spare parts arrive and repairs are complete, passengers should expect delays and check for live service updates before making their journeys.
