New Piccadilly Line Trains Undergo Testing Ahead of 2026 Launch

Three of the new Piccadilly line trains have now arrived in London for extensive testing, with a fourth unit expected to join them shortly.

These next-generation trains are part of a major upgrade to the London Underground and are currently undergoing assurance testing to ensure they integrate properly with existing Tube infrastructure.

Transport for London (TfL) documents reveal that initial testing focused on the physical fit of the trains within stations and tunnels—a process that proved more challenging than expected earlier this year. Slight differences in carriage length and other design elements required additional adjustments, which led to a rephasing of the early testing schedule.

Initial test runs took place in late July, followed by further trials during a planned weekend closure in August. Most recently, system testing has begun. This phase evaluates how the new trains interact with operational railway systems, including communications and signalling.

Looking ahead, TfL will carry out reliability and performance testing, with plans to begin staff training in 2026. Alongside this, infrastructure upgrades are underway, including enhancements to signalling, power supply, communication networks, and station platforms. Depot and stabling facilities are also being updated to support the new fleet.

The new trains are now expected to enter passenger service in the second half of 2026, later than the originally projected date of late 2025. Once all 94 trains are in operation, TfL plans to increase peak service frequency from 24 to 27 trains per hour.

Up to 80% of the fleet is being manufactured at Siemens Mobility’s new UK facility in Goole, Yorkshire—providing a boost to British industry.

These modern trains will offer several upgrades for passengers, including:

• Walk-through carriages for easier movement between cars

• Wider, double doors for faster boarding and disembarking

• Enhanced passenger information via digital displays

• CCTV for improved on-board security

• Air conditioning—introduced for the first time on a Deep Tube service

  
  

The new trains will increase line capacity by 10%, while improving energy efficiency and accessibility across the Piccadilly line.