A ground-breaking initiative that transforms passenger trains into mobile inspection units is being rolled out across more routes in South-East London, Kent, and East Sussex—marking a significant step forward in proactive rail maintenance and performance management.
South Eastern Railway—a collaboration between passenger operator Southeastern and infrastructure provider Network Rail Kent Route—is scaling up its use of train-mounted thermal imaging technology to detect faults before they disrupt services.
Earlier this year, a pilot scheme saw thermal cameras installed on a select number of Class 707 ‘City Beam’ trains. The results were compelling: 41 overheating incidents were identified early, preventing over 9,000 minutes of passenger delays.
The technology, developed by AIVR specialists One Big Circle, is now being fitted to 20 Class 375 ‘Electrostar’ Main Line trains, in addition to the 12 Class 707 units already equipped. While other UK operators have trialled similar systems, South Eastern Railway is the first to commit to permanent, large-scale deployment of on-board AI monitoring.
This expansion means both Metro services in South-East London and longer-distance Main Line routes will benefit from real-time infrastructure monitoring—enabling faster response times and more targeted maintenance interventions.
The AI-powered thermal cameras detect ‘hot spots’ on the network and transmit data directly to asset engineers, who can assess whether repairs are needed. This not only helps prevent service disruption but also reduces the need for physical site visits, improving safety and operational efficiency.
Rail Minister Lord Peter Hendy commented:
“This Government is fundamentally reforming how our railways are run, creating a network that works better for the people and freight using it.
The cutting-edge technology South Eastern Railway is installing on its trains is key to achieving this and should serve as an example of the kind of smart investments we’re making as publicly owned rail companies work to improve services.
These upgrades will prevent disruption and reduce delays, supporting local jobs, growth, and housing as part of the Government’s plan to deliver an efficient and reliable railway.”
Dan Paris, Fleet Maintenance Director at South Eastern Railway, added:
“Our integrated railway is using train-borne cameras to provide the early warnings we need to identify and fix problems before they cause disruption for our customers.
The cameras on the City Beams are monitoring our London Metro routes and now with a new set of cameras being added to 20 of our Class 375 trains we can look out for any issues on a much wider area across East Sussex and Kent. I’m confident that they will really help us in our drive to improve performance and reduce delays.”
Emily Kent, Director of One Big Circle, praised the collaborative effort:
"It's been fantastic to work with South Eastern Railway to deliver this cutting-edge technology onboard the fleet. The can-do spirit and collaboration of all involved has ensured faster, more effective outcomes that will bring real benefits to passengers and staff across the network."
In a further enhancement, five of the Class 375 trains will also be fitted with underbody cameras. These will monitor track slipperiness and assess the condition of the train’s ‘shoe’ and conductor rail—critical components for power transfer. This data will be especially valuable during adverse weather, helping to maintain performance and safety.
Image and video credits: Southeastern
