Transport for London (Tfl) is advising Piccadilly line customers to plan their journeys carefully during a series of upcoming closures, as major upgrade works continue to prepare the line for a brand-new fleet of trains entering service from December 2026 through to June 2027.
The closures form part of a complex programme of infrastructure upgrades and operational testing required to support the introduction of the new Piccadilly line trains. Once in service, the fleet will deliver significant customer benefits, including walk‑through carriages, improved reliability and frequency, enhanced accessibility, air‑conditioning and comprehensive on‑board CCTV.
Preparing century‑old infrastructure for a new generation of trains
TfL is using the planned closures to carry out essential work on power systems, track, platforms, depots and sidings, while continuing to test how the new trains interact with existing London Underground infrastructure. Much of this infrastructure is more than 100 years old and interfaces with multiple other lines, making extensive testing critical before passenger service begins.
During previous part‑closures, TfL has already completed weight‑load testing of the new trains, covering 400km with a fully loaded test train weighing 68 tonnes. Engineers have also undertaken works at 119 Piccadilly line platforms to ensure they can safely accommodate the longer trains and their different door configurations.
Some closures are also being used to complete essential routine maintenance, including the renewal of points in the Hounslow area between 28 and 31 May, helping to safeguard the line’s long‑term reliability.
Where possible, weekday closures have been scheduled during school holidays, when demand across the network is typically lower.
When and where the Piccadilly line will close
While most closures will take place at weekends — typically from 00:30 on Saturday (meaning Friday Night Tube services are suspended) until the end of service on Sunday — several closures will also affect weekdays.
These include:
- Acton Town to Heathrow and Rayners Lane to Uxbridge from Thursday 28 to Sunday 31 May
- Cockfosters to Uxbridge on Thursday 30 and Friday 31 July, and Monday 3 August
- Cockfosters to Heathrow on Saturday 1 and Sunday 2 August
- Two sets of midweek closures (Tuesday to Thursday) from Cockfosters to Uxbridge:
- 18–20 August
- 25–27 August
During these periods, the Metropolitan line will continue to operate normally between Rayners Lane and Uxbridge, providing alternative travel options for customers.
A £3.4bn investment in the Piccadilly line’s future
The new trains form part of a £3.4bn investment to modernise the Piccadilly line and improve reliability, safety, inclusivity and sustainability across the route.
Each train offers 10 per cent more capacity while being lighter than the current fleet, reducing energy consumption by 20 per cent and delivering a smoother ride. The expanded fleet will allow peak frequency to increase from 24 to 27 trains per hour, boosting peak capacity in central London by 23 per cent.
The trains also introduce air‑conditioning for the first time on the Deep Tube network, made possible through an innovative articulated design.
Four of the new trains are already undergoing testing on the Tube network during overnight engineering hours and weekend closures. In the coming months, customers will begin to see the trains tested during passenger service hours.
Stuart Harvey, TfL's Chief Capital Officer, said:
"I'd like to thank our customers for their patience while we carry out these essential upgrades to the Piccadilly line and rigorously test the new trains which will transform journeys for many decades to come. Introducing a new fleet of trains is a huge engineering and logistical feat which inevitably requires upgrades and intensive testing. Although much of the hard work goes on behind the scenes, there are times when we need to close sections of the railway to ensure that these pioneering new trains can operate effectively and interact correctly with a wide range of complex infrastructure. We are very confident that once this intensive period of upgrades and testing is completed, and the new trains start to enter service, our customers will reap the benefits of moving around the capital on these game‑changing new trains."
Image credits: iStock
