London’s next generation of Tube trains has been formally unveiled in Berlin, at the world’s largest rail trade fair, in what reports from the event describe as the first time Transport for London has ever displayed a vehicle at InnoTrans in its 30-year history.
The new Piccadilly Line train — one of the 94 Siemens Mobility-built vehicles ordered by TfL in a £1.5bn deal — was showcased at InnoTrans on 24 September. Siemens lists a “Piccadilly line train Showcase” in its official InnoTrans 2026 programme, and trade coverage from the fair frames the unveiling as a first for the capital’s transport authority. There is, notably, no official TfL press release on the unveiling; the account of the event comes from Rail Business UK, which reported from Berlin.
The trains, known as 2024 Stock, will replace the Piccadilly Line’s 86 existing trains once the full fleet of 94 is delivered. The £1.5bn contract with Siemens Mobility was announced in June 2018, with the final contract award following in November 2018 — making it one of the biggest rolling-stock investments in Underground history.
When they enter service, the new trains will bring walk-through carriages, wider all-double doorways and — most significantly — air-conditioning, a first for a deep-level Tube train. On a line whose tunnels trap summer heat, cooled carriages are the single biggest change passengers will notice. Details of the fleet renewal are set out on TfL’s Piccadilly line upgrade page.
Four of the new trains are already in London, according to TfL Commissioner Andy Lord. The figure comes not from an official TfL document but from Lord’s on-the-record speech at the Railway Industry Association’s InnoTrans reception on 23 September, as reported by Rail Business UK.
On the timetable for passengers to actually ride them, TfL’s current official position is that it is “working to a window of between December 2026 and June 2027” for service entry. Lord, however, told the reception that entry into service is unlikely before 2027 — a genuinely new detail that suggests the later end of that window is the more realistic bet.
The Piccadilly line renewal sits alongside a wave of rail investment across the capital, from Southwark’s push for the Bakerloo line extension to unlock 100,000 homes to the ongoing West London Orbital consultation. But the new trains are the most tangible upgrade of all: passengers should expect noticeably cooler journeys, more space to move through the train, and faster boarding thanks to the wider double doorways — changes designed to cut dwell times at packed stations like King’s Cross St Pancras and Heathrow.
For regulars on the line, the change cannot come soon enough: packed rush-hour services through central London and out to Heathrow will be cooler, roomier and easier to board. The walk-through design lets passengers spread along the train rather than bunching at the doors — a small shift that should ease some of the worst crushes on the network.
Reporting based on Rail Business UK.
