New Piccadilly Line trains delayed until second half of 2026

London Underground’s brand-new Piccadilly Line trains will not enter service until the second half of 2026, almost a year later than planned.

The first of 94 new trains were due to carry passengers before the end of 2025, but Transport for London (TfL) has said testing will take longer than originally planned.

TfL said that since the first unit was delivered in October 2024, engineers have identified and understood the challenges that need to be overcome before they can enter service.

“This process has identified it is more complex than expected”, a statement said.

“As a result, the start of a rigorous programme of testing the interactions with the infrastructure and systems has had to be rescheduled.

“Siemens Mobility and TfL have been working together to address these issues, which will allow testing to start in the summer. All mitigations or design alterations will be incorporated into all future trains.”

TfL has said enough time is needed to test the interactions between the train and much older infrastructure to ensure they are “safe and reliable”.

Stuart Harvey, TfL's Chief Capital Officer, said: “It will obviously be disappointing for customers that they will have to wait a bit longer for the new trains, and I regret that.

“But I would like to assure Londoners and visitors to our city that we are working extremely closely with Siemens to ensure that the new trains can be introduced as soon as possible in the second half of next year.”

The new fleet is part of a £2.9 billion modernisation programme that will also make the Piccadilly Line more accessible and sustainable. The 94 new units will replace 86 dating back to 1973.

Around 80% of the new trains will be built at Siemens’ new factory in Goole, which opened in early October last year. The others, including the first example, are being built in Vienna.

Once all are in service, train frequency will increase from 24 per hour to 27.