Siemens Mobility and Transport for London (TfL) have presented the new Piccadilly line train at InnoTrans 2026.
The new train will be the first air-conditioned train designed for London’s deep-level Tube network. Its introduction will improve conditions for passengers while increasing capacity and reliability on the Piccadilly line.
At the event, Siemens Mobility CEO Michael Peter explained how the company has used digital engineering to address the constraints of London’s deep Tube infrastructure.
The train uses regenerative braking technology to reduce the amount of heat released into the tunnels. According to Siemens, this changes the thermal conditions in the tunnel sufficiently to make air conditioning possible while also reducing energy consumption.
The train has also been designed around the restricted dimensions of the deep-level Tube. Its aluminium car body uses a bionic structure to reduce material and weight, while the interior layout is intended to maximise usable passenger space.
Siemens Mobility’s UK and Ireland CEO, Aglaja Schneider, noted that engineers worked to make use of “every single millimetre” available within the tunnels. The design includes articulated bogies, walk-through carriages and air-conditioning equipment integrated beneath the seats.
The new trains will also introduce digital monitoring across the fleet. Siemens’s Railigent X platform will collect real-time information on the location and condition of components including HVAC systems, doors and traction drives.
Data analytics will then be used to identify potential faults before they occur. For example, monitoring small changes in HVAC electrical current can help identify developing issues and trigger information to be sent to the depot, allowing maintenance teams to intervene before a failure takes place.
Andy Lord, Transport Commissioner for London, said the new trains would provide customer features that have not previously been available on the deep-level Tube. These include live customer information, walk-through carriages and greater standing height around the doorways, alongside air conditioning.
Andy Lord, Transport Commissioner for London said:This train delivers customer enhancements that we've never seen before on the Deep Tube: live customer information, walk-through carriages — the ability for anybody over more than 5'10 to stand vertically in the doorways! And of course, as already mentioned, and so important after the summer we've just had in the UK, the first deep tube trains to have air conditioning, which really is transformative for the customer experience.
The Piccadilly line’s existing trains entered service more than 50 years ago. The replacement fleet is intended to improve reliability and increase capacity as passenger demand grows.
Four of the new trains are currently undergoing testing in London. Lord said the trains would become increasingly visible on the network in the coming weeks, ahead of their eventual introduction into passenger service.
The programme is also supporting UK manufacturing. Siemens said the first 20% of the fleet was manufactured in Vienna, while the remaining 80% is being assembled at its Goole rail manufacturing facility in East Yorkshire. The Goole facility forms part of a reported 240 million GBP investment and has also supported apprenticeships, graduate roles and STEM initiatives in the region.
View interior and exterior images of the new train here.
