Test operations are well underway for Berlin’s new-generation U-Bahn trains, with ten Stadler-built vehicles currently in use for trials on the city’s network. The first of these trains are scheduled to enter passenger service on lines U5 to U9 in 2026.
Stadler U-Bahn trains: Testing underway across the network
The renewal of the U-Bahn fleet is a central element of Berliner Verkehrsbetriebe (BVG)’s long-term strategy to improve service reliability and operational performance. The ongoing trials represent a key milestone in this process. Ten test units are now actively running across the network, frequently visible between regular passenger services.
For the first time, a fully assembled six-car Type J train is stationed at the Friedrichsfelde depot. This prototype train, stripped of passenger seating to reveal its internal systems, is currently undergoing a range of assessments. These include evaluations of braking performance and tests on how the train’s individual modules—making up a total length of approximately 100 metres—interact with each other.
The comprehensive testing programme is designed to assess all safety-critical and operational systems, including environmental considerations, before official approval is granted. Recent trials have included acoustic measurements to ensure compliance with noise standards. BVG has emphasised that accuracy and thoroughness are essential, as this new generation of trains will be in service for decades to come and is expected to deliver improved reliability and passenger comfort.
“The test results so far make us very optimistic,” said Henrik Falk, CEO of BVG. “The new trains are an important building block for greater stability in the system. But it’s not just important that the technology works. The trains should also help people feel comfortable on the metro – with modern design, a sense of space, and comfort. Our colleagues are already excited about the modernization of the fleet. Our passengers will soon be able to experience what the future of the metro in Berlin will feel like.”
In addition to their more spacious interiors, the new trains offer several other passenger-oriented innovations. Features include an advanced passenger information system, an improved lighting concept, larger door areas, and increased accessibility for individuals using wheelchairs or travelling with prams and luggage. A redesigned driver’s cab and more ergonomic controls also aim to improve conditions for BVG personnel.
The Type J trains are wider than their predecessors and are scheduled to commence passenger service in summer 2026. Ahead of that, training sessions for drivers, maintenance staff and station managers will begin in early 2026.
Progress on the narrower JK series trains, designed for the U-Bahn’s small-profile lines (U1 to U4), is already more advanced. Staff training is currently in progress, and passenger service is set to begin after the summer holidays. Simultaneously, full-scale series delivery of the JK cars will commence, with up to 140 vehicles expected to enter service by the end of the year. Development of the JK series was prioritised due to the increased technical complexity of fitting necessary systems into smaller vehicles, and lessons learned during their development informed the design of the wider J trains.
“The new J and JK series U-Bahn trains represent a technological quantum leap for Berlin passengers,” said Jure Mikolčić, CEO of Stadler’s Germany Division. “With a completely integrated car design and state-of-the-art communication technology, we, together with BVG, are setting new standards in safety, comfort, and accessibility.”
Largest procurement in BVG’s history
The procurement of the J and JK series represents the largest rolling stock contract in BVG’s history. Under the framework agreement signed with Stadler, up to 1,500 cars may be delivered by 2035.
The full contract is valued at up to EUR 3 billion and includes the supply of spare parts over a 32-year period. Current confirmed orders comprise 484 cars, scheduled for delivery by 2027.
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