Pioneering Railhead Low Adhesion Monitoring Trial Extended Following Successful First Year

The bottom half of a train
As the autumn leaf fall season begins, Knorr-Bremse Rail Systems UK and Chiltern Railways have announced a 12-month extension to their joint trial in capturing real-time adhesion monitoring which will quantify wheel to rail adhesion levels, building an understanding of how conditions can change across the network.
Originally launched in August 2025, the low adhesion monitoring trial has seen the technology installed on a train (Class 165), operating on the Chiltern Main Line and London to Aylesbury route. Jointly developed by Knorr-Bremse and Chiltern Railways, with support from Angel Trains, the project is providing the rail industry with unprecedented insight into low adhesion conditions at the wheel to rail interface.
Now, and in order to prove the real-world concept of providing even richer data, the trial has been extended to August 2027. This will enable data to be captured for a second autumn leaf fall season while further refining the technology and expanding engagement across the rail industry.

John May, Digital Services Business Development Manager at Knorr-Bremse Rail Systems UK, said:

“Data collected through our railhead low adhesion monitoring system has the potential to provide rail industry customers with a much clearer understanding of not only when low adhesion has occurred, but also where it is happening and what action may be needed to address it.

“The success of the first year of the trial has demonstrated the value of real-time adhesion monitoring. The quality of the data collected means we can identify low adhesion hotspots and seasonal trends with a high degree of accuracy. Extending the trial will strengthen the dataset further and help demonstrate how this intelligence can support a more proactive approach to managing low adhesion.

“As the trial enters its second year, our team believes the technology has the potential to transform how low adhesion is understood and managed across the UK rail network, enabling smarter interventions, more targeted railhead treatment and improved operational performance during challenging seasonal conditions.”

Unlike conventional systems that indicate only when wheel slide or traction slip has occurred, the Knorr-Bremse system calculates wheel-rail adhesion values during braking events, notably in the moments before and after a WSP activation; an invaluable insight that the industry did not previously have. This enables engineers to assess the actual condition of the railhead and understand how slippery it is in operational service.

Since entering passenger service in September 2025, the instrumented Class 165 unit has continuously captured adhesion, braking, wheel slide and traction data without affecting normal operations.
By February 2026, the train had covered more than 45,000 miles, recording over 500-wheel slide events and 850 traction slip events across a range of operating conditions, including autumn leaf fall and adverse weather. The system has enabled engineers to identify low adhesion hotspots with an accuracy of just a few metres while monitoring variations in adhesion levels between individual axles during braking.
The high-resolution data is also supporting the work of the Rail Safety Standards Board’s Adhesion Research Group (ARG) and wider industry research into low adhesion behaviour.
Louis Schmandt, Technical Engineer at Chiltern Railways and project lead, said: “In the last year, excellent progress has been made in processing and understanding the vast pool of data that has been captured as well as refining and tailoring the User Interface to better suit the needs of the end user. Data analysis is now possible at both at a high, network-wide level as well as for investigating incidents in detail. 
“Individual parameters can be selected as required to obtain the required information. Adhesion hotspots have been identified in areas that were not previously considered by Chiltern and Network Rail and a lot of progress has been made in better understanding the kinematics behind low adhesion events – in particular in the milliseconds in the lead up to and immediately following a WSP activation.
“This is very much in line with the main objective of this initiative; to develop a model which acts as the industry’s primary means of predicting low adhesion risk at any location and given time throughout the year. The next challenge will be to build on this capability and enable the WSP system to proactively utilise this data to directly control the train’s response to low adhesion, thereby reducing dependence on infrastructure mitigation measures or driver behaviour.
“There is now a strong case to scale up this trial to include additional units both at Chiltern and across other networks. This would help demonstrate the full potential of this concept, both in terms of predicting low adhesion risk to aid operators and infrastructure managers in their decision making as well in providing further technical insight for incident investigations and informing delay attribution.”
It is the latest in Knorr-Bremse’s pedigree of providing technical innovations to the rail industry. Another example of its work in this sphere that is already on the network and delivering lasting solutions is ‘FreightControl Sentinel’, a pivotal part of the multiple award-winning iWagon, which Knorr-Bremse collaborated on with its partners at VTG Rail UK.
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